"Our everyday world, plainly moulded by subatomic forces, also owes its existence to our universe's well tuned expansion rate, the processes of galaxy formation, the forging of carbon and oxygen in ancient stars, and so forth. A few basic physical laws set the 'rules'; our emergence from a simple Big Bang was sensitive to six 'cosmic numbers'. Had these number not been 'well tuned', the gradual unfolding of layer upon layer of complexity would have been quenched. Are there an infinity of other universes that are 'badly tuned', and therefore sterile? Is our entire universe an 'oasis' in a multiverse? Or should we seek other reasons for the providential values of our six numbers?"
Martin Rees
Martin Rees: Just Six Numbers
There are a small number of key physical constants that had they been slightly different would have led to our Universe developing very differently.
Figures of speech
Perhaps appropriately for a book that is about 'just six numbers' I wish to examine some of the figurative (see what I did there?) language used by an author in seeking to explain some abstract scientific ideas for a popular readership.
I have written quite a lot in this blog about the kinds of metaphorical and other figurative language used by teachers and other science communicators when trying to explain science, and here I want, in particular, to make a point about context: about the context in which such language is used,
"A technique that chemistry teachers share with teachers of other disciplines, as well as other communicators (such as journalists, but, indeed, people in general) is to draw comparisons with (what are assumed) familiar ideas, experiences and phenomena, simply by using language. This can be in the form of metaphors, similes and analogies…and these can sometimes be anthropomorphic in nature – that is, to put something (such as the 'behaviour' of a molecule) in terms of human feelings, thoughts and experiences.
Although, later, I make a distinction between metaphors, similes, and analogies – in practice, it is not always straightforward to distinguish between them. For example, our judgement about which category some comparison belongs in may change depending upon whether we consider a specific statement by itself, or examine it in the wider context in which it occurs. That is, material of relevance that is not explicit in the statement may be being assumed by the communicator as it has been previously referenced or alluded to, as part of the wider text or dialogue."
Taber, 2024
In a science classroom, that context might include earlier topics presented in the curriculum; some reading that was set ('homework') as preparation for class; what the teacher said last lesson; or something learners have just been asked to try out or to observe. In a text, such as an extract from a popular science book (as in the example above from 'Just Six Numbers'), the context that is provided is the rest of the text, and especially the part of the text preceding that extract – as this is the part an author can reasonable claim you 'should' have already read (though readers are of course free to engage with a book as they wish).
That is, 'should' does not here imply an imperative, but rather the author's reasonable defence that if you choose to read the text out of order, or just dip in, then the author cannot be considered to be responsible for anything you may have missed that is needed to make good sense of what is presented later in the book. Any teacher who has pointed out to a student claiming not to follow in class that they 'might have understood better if they had not missed the previous lesson' can appreciate this logic.
Interrogating the text
So, bearing in mind I have not reproduced the whole of Prof. Rees's book, but just an extract out of context, I would like readers to consider the extract at the start of this posting, and to ask themselves:
what does this mean?
how do I know what it means?
what would it be reasonable to expect a 'typical' general reader (one with an interest in the topic, but not being a science specialist) to make of the extract?
what terms or phrases in this extract can be considered to be used figuratively here (that is to not here strictly mean what those words, strictly, mean?)
I noticed this extract was rich in figurative language, such as metaphors with teir 'hidden' meanings. And then I re-read it, and further noticed I had actually read-through some of the metaphorswithout initially noticing them – so it was actually even richer in such language than I had first realised.Often we do not notice the metaphors and similes used in texts, but rather simply automatically make sense of them as part of the text. 1 Usually we read a text for meaning (semantics) rather than choice of vocabulary, and we 'automatically' (preconsciously) analyse the text in terms of pragmatics – that is what a term is likely to mean in this specific context:
I am going to the bank to cash this cheque
I am going to the bank to dangle my feet in the river
I am going to the bank to see if we have any AB negative
Language is fluid (so to speak)
The extract from Rees's book presents a range of terms which need to be interpreted to identify what they mean within this particular context. Now I do not intend this as a criticism: I think two relevant general principles here are that:
It is the nature of natural language (e.g., here English – 'other natural languages are available') to be somewhat fluid (so to speak), with many words and phrases being open to somewhat flexible use across a range of meanings: so it is generally the case that words, phrases, sentences, paragraphs, etc., take their specific meanings within a text from the wider textual context.
And indeed, in everyday situations, also the broader shared context. If someone is shouting out 'Fire!' this may mean something quite different in the context of a quiet accounts department in a tall office block than in the context of a Fascist's state's execution of a political prisoner – or indeed at an Arthur Brown concert.
When musician Arthur Brown performed his song 'Fire', and sang loudly 'Fire!', he did not intend his audience to leave the venue. (Though given his stage headgear, which sometimes malfunctioned, a careful risk assessment might have suggested that course of action.)
It is in the nature of unfamiliar abstract science concepts that they will not make good sense to learners (/readers/listeners) who cannot relate them to something already familiar. So science teaching (and science communication more generally) is often about making the unfamiliar familiar by showing how this unfamiliar idea is a bit like something you already understand and are comfortable with. This unfamiliar thing is not the same as that familiar thing (and differences will need to be addressed), but there is a similarity which can be used as a starting point for making the unfamiliar familiar.2
Using figurative language to explain science is therefore not a bad thing – although there can be poor examples which do not help or only confuse as well as very productive examples that support learning (and this may be relative to individuals, as each learner brings their unique set of 'interpretive resources' to make sense of learning). And indeed, sometimes, it may be a necessary teaching tactic if the gist of an abstract idea is to be effectively communicated. My discussion of examples in this blog then is certainly not intended to mock or deter this technique, but rather to highlight something of the complexity of using figures of speech in explaining science.
Let's start at the end…
The extract I present above is from the end of the book, as Prof. Rees concludes by summing up what he has been setting out to readers. This is then (most of) the very final paragraph in the text, so it is quite reasonable for Rees to assume that a reader getting to this point will have the context of having (in effect) read the book.
If you have not read the book, then perhaps that extract above may be too dense with ideas and figures of speech for you to fully appreciate it. But that depends: if you are a cosmologist or astronomer or physics teacher, then it is quite likely that you are sufficiently familiar with the ideas being communicated (and indeed some of the metaphorical language being used) to find the extract unproblematic. As always, each person brings their own unique set of interpretive resources to make sense of a text.
But, as an example, I am going to deconstruct the text to highlight some of the 'interpretation' involved in understanding it. Now, there are references made in the extract to scientific ideas which had been discussed earlier in the book, such as that of a multiverse, the Big Bang, and the expansion of the Universe. But my focus is on the non-technical figurative terms, or at least those that are likely seem non-technical to the general reader. 3
Tuning up the Universe
The terms well tuned (and in the marked form, 'well tuned') and 'badly tuned' are applied to the Universe. This notion has been well developed earlier in the preceding text. Tuning is originally a term used in relation to musical instruments that is figuratively used in other contexts. One might tighten the tension in a guitar string so it plays at the right frequency to give the required musical note.
Engines are also said to be tuned. Presumably this was originally used metaphorically, and because the process was done 'by ear' – by listening to the engine 'note'. Language develops over time so that engine tuning has become an accepted term and is no longer metaphorical. However, clearly there is something of a stretch (so to speak) to extend the notion of tuning to a universe. 4
Being well tuned (or badly tuned) is anthropomorphic or teleological. That is, there is nothing intrinsically right or wrong about a universe having particular qualities. But for a universe to have been suitable for us to appear it needs certain properties – a well tuned universe is one that has particular qualities that are seen (by someone) as desirable. Being well tuned might then imply developing in accord with some sense of purpose. (Again these ideas had been addressed earlier in the text by Rees for anyone reading the whole book.) 5
Moulding and forging
To mould means to shape something, perhaps (as with clay) by manipulation or (as with cooling molten metal) by pouring in a pre-shaped mould. The term is widely used metaphorically, and here the term is extended to the effects of subatomic forces.
Forging is a term relating to metal working, where a blacksmith (for example) uses a forge as a hot environment to shape (and sometimes harden and temper) metals. The forge is (in human terms) very hot – although the forging is itself achieved by hammering the metal once it is hot enough to be sufficiently malleable. The term is again commonly used metaphorically – perhaps a famous example was a much quoted speech by UK Prime Minister Harold Wilson who referred to how his government was
"…re-stating our Socialism in terms of the scientific revolution…. Britain that is going to be forged in the white heat of this revolution…"
The processes by which heavier atomic nuclei (i.e., anything heavier than helium nuclei in this context) are produced are nuclear process that only occur under what we would consider extreme conditions such as in the cores of suns (often considered 'nuclear furnaces') or during supernovae explosions or other events that irradiate material in space with highly energetic radiation. There is no forging as such, but the conditions may be seen as akin to those in a forge – e.g., unusually hot. If using 'forging' metaphorically to refer to the nucleosynthesis of elements, it is important to note that in the scientific context an important aspect of the original meaning does not transfer across: the blacksmith uses his forge to deliberately produce something, perhaps horseshoes, whereas there is no deliberate purpose or design to the nuclear changes going on in stars. 6
Unfolding the layers
The "gradual unfolding of layer upon layer of complexity" offers something of a mixed metaphor. We might argue that by definition it is only possible to unfold something that has previously been folded. But metaphorically we might see the opening of a flower, with its sepals and petals and pistil and stamens as being like a kind of unfolding – we can imagine these structures have been neatly folded away, though of course that never happened.
We might also say, metaphorically, that a story unfolds as new themes and characters and episodes are introduced (though here there is a sense that the author who planned the narrative has likely story-boarded this level of detail, and then (metaphorically) folded it away in the structure of the narrative.
The (metaphorical) unfolding referred to by Rees seems to be akin to that of a flower, in that as the Universe ages new structures appear through a developmental process just as the new organs appear on a plant when the flower develops. (Incidentally, astronomers tend to refer to the 'evolution' of the Universe although clearly there is no evolution in any sense parallel to that seen in organisms – through variation and natural selection. A better analogy would seem to be with the development of an individual living thing that passes through different stages of life.)
The layers of complexity are surely metaphorical, as it is only human cognition which finds it convenient to see them as layers. We can see the world in terms of a series of strata of increasing complexity with new phenomena emerging at the different 'levels': so perhaps sociology from psychology, which emerges from biology, chemistry, and ultimately physics.
We can consider structure in the Universe at 'levels' such as galactic clusters, galaxies, stellar clusters, solar systems…nuclei, quarks, etc. But in the Universe these do not occupy actual levels, rather this is an abstraction we impose to help analyse the complexity (we 'dig down' to the 'level' of molecules or nuclei or quarks or whatever). This is probably obvious to most readers as we are so used to imposing metaphorical layers on conceptual systems (but it might mystify a perfectly normal modern human who had not received a formal education 7).
Quenching
Quenching takes us back to the forge. I strongly remember metal work at school when I was eleven, and having to heat a piece of metal till it glowed a particular colour before plunging it into cold water to 'quench' it: to cool it rapidly. Having hardened the metal it was next 'tempered' by heating again before being thrust into sand to cool less rapidly. While I have forgotten much I did at that age at school, the sheer fear of using lathes, massive drills and blowtorches provided an emotional quality that seems to have 'forged' those memories. (But I do still have the screwdriver I made.)
One can also use water to quench a fire or one's thirst – so quenching is a process of removing. In Rees' text the metaphorical layers of complexity would not have occurred, and so could not have been metaphorically unfolded if the 'six numbers' had had very different values. Some minor shift in one or more of those numbers may have changed the timescale of universal development, so that some of the processes and structures in our Universe would not have had time to develop, or to have developed as much.
In either case it is only a potential which is 'quenched' as nothing that comes into being is removed, and there is no active quenching agent – it is more a (metaphorical) lack of formation of the combustible material than the action of some water to put out a fire.
Does this make for a poor metaphor? This is quite difficult to judge as words have aesthetic and other qualities (such as salience) as well as literal meanings, and a metaphor which seems less apt semantically may still have some impact on a learner/reader/listener and lead to engagement with the ideas being communicated. (And this will vary between individuals of course.) So the crux of the question of whether 'quench' is a good choice here is an empirical one: if it helps communicate Rees's intended meaning to (most of) his readers then it is effective: if instead it mainly mystifies or confuses or misleads them, then not so.
A desert of sterile universes?
If there are other universes which developed with different values of the key cosmic constants (constant, in any particular universe, that is) then in many of those universes there would be no galaxies and stars. And in some that did lead to galaxies and stars there would be no opportunities for life to evolve (if stars burned out rapidly, for example). And in some that gave opportunities for some kind of simple life, there would not be sufficient scope for the evolution of sentient beings capable of asking questions about other universes.
If sterile means unable to reproduce, then this is a metaphor which could be applied to any universe. 8 Sterile can also mean free from organisms (usually especially microorganisms) which could therefore seem as a non-figurative term when applied to some imaginable universes (which might include stars systems etc., but that are) incapable of supporting life.
If there is a multiverse – that is, if our Universe is one of many coexisting but completely non-communicating universes – where the different universes have widely different values of these cosmological constants, then likely most of them will not have developed with the complexity of ours, and so most would not support the evolution of life. Thus if we see the multiverse as a desert, then, metaphorically, a universe like ours would be an oasis – a small location where life can survive in the desert.
The metaphor requires us to step out of our Universe to take a view of the multiverse, and imagine a traveller moving across the desert and entering the oasis; when the 'oasis' is actually a self-contained world, not even hermetically sealed off (so to speak) from any other such worlds as it has no boundary with them, and there is no means of seeing out beyond the oasis. No traveller could move from one universe to another (so there would be no opportunity to look back in anger if they found the grass was not actually greener).
Is the universe like an oasis? (Image by AlexBishop from Pixabay)A galaxy – an island universe? (Image by Kyoung-Sik Choi from Pixabay)
Despite this, my own feeling is this metaphordoes communicate a meaning well, and it reminds me of a long-established metaphor where galaxies are seen as their own island universes in the ocean of space. 8 So again, I do not think we can judge the effectiveness of metaphor simply in terms of the technical aptness of that metaphor, but this does remind us that in interpreting a metaphor the reader or listener is selecting some, but not all, of the associations available for the term (and so of course may select different associations to those the author or speaker had in mind).
Coda: Texts may have their own dark matter
What this analysis is intended to do, is not to critique the specific figures of speech used here (which can only sensibly be evaluated by questioning a representative sample of readers who had finished the book to see how they made sense of the text), but rather to highlight just how many layers of complexity may be enfolded (so to speak) in forging even a short text, and so just how much interpretive work a reader needs to do in making sense of a text.
We think of scientific articles as being as explicit and precise as possible, and so rich in formal technical language; and this is appropriate as the intended readership can be expected to have mastered the relevant concepts and technical vocabulary necessary to make sense of such a text. But in explaining science to a non-expert audience (in teaching; in writing a popular science book) one has to mould an account to resonate with the audience members' available funds of interpretive resources. These resources may be rich and varied, but will be technically more limited.
So such texts can only be populated with the lower density of technical ideas and terminology that can either be assumed as common to the audience, or gradually introduced in the text. Technical terms therefore are widely interspersed among the 'space' of the text, with the meaning being held together by the use of figurative language such as metaphors with their 'hidden' (implicit) meanings. The work of making sense relies on a good understanding of the technical terms used, and a suitable interpretation of the supporting 'dark matter' of figures of speech.
Usually, most of this interpretive work is automatic – occurring outside the 'spotlight' of conscious awareness – but the reader still has to process the text to try and mould it into a reading that makes sense to them. A text needs to be well-tuned for its readers, or else that sense-making will be quenched, making the metaphors sterile. (So to speak.) Or worse? Perhaps being fertile grounds for unintended meanings to germinate.
This 'tuning' is always a challenge given that different readers will have different levels of background knowledge and other interpretive resources, and so may resonate across a wide range of different natural frequencies, so to speak. A well judged (tuned) book will at least largelyresonate with most of its readers regarding most of the metaphors used. Then they will likely not even notice these figures of speech, as interpretation will be automatic and the text will simply, subjectively, make sense. Somewhat like the dark matter thought to make up much of the mass of the Universe, these figures of speech hold the text together semantically without being conspicuous. Of course, sometimes the wrong feature of the metaphor may be adopted, so the reader's meaning may not perfectly match what the author intended.
There may be outliers, including perhaps some readers not well prepared to tackle the text (lacking essential background knowledge or reading level perhaps) who may find themselves in a metaphorical semantic dessert with just the odd oasis that seems fertile with meaning. (So to speak.) An author, unlike a teacher, does not have the opportunity to constantly check on how they are being understood and make adjustments, so this is an unavoidable feature of texts of this kind.
All an author can do is choose their metaphors carefully, bearing in mind their expected readership; and offer context by incrementally forging a kind of customised metaphorical lexicon across the text. 9 As Rees does in his book.
If you are intrigued by the extract discussed, and wish to know more, the full textual context (Rees, 1999) is available!
Sources cited:
Luria, A. R. (1976). Cognitive Development: Its cultural and social foundations. Harvard University Press.
Rees, Martin (1999) Just Six Numbers. The deep forces that shape the Universe. Weidenfeld & Nicolson. London.
1 By similes I mean those figures of speech which are marked by the author, for examples using inverted commas (speech marks) as in 'well tuned' as in "…not been 'well tuned', the gradual…", as well as metaphors such as well tuned in "our universe's well tuned expansion rate". Similes may also be marked by using like, as, in a sense, so to speak, etc.
Many examples of science similes are listed in 'Creative Comparisons: Making Science Familiar through Language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
We usually 'read through' such figures of speech, but as I have become rather obsessed with the use of figurative language in science I tend to notice many of them, often reading a text both for the scientific meaning and also to see the way the author is explaining the science.
3 I make this distinction because sometimes terms which are originally used metaphorically, such as the 'death' of a star, come to be habitually used; and so in effect become technical terms within a scientific field, while still appearing to be metaphorical to a non-expert in that field. They become phantom metaphors (something a non-expert will assume is a figure of speech, although it is being used as if a technical term).
4 Traditionally the Universe referred to everything there is, but (following Rees in his text) we can both consider other potential universes that could perhaps have existed instead of ours, and also that there may be totally separate non-communicating alternatives beyond what we can observer as our Universe which potentially have quite different natural laws. In this usage 'our' Universe may be one element in a 'multiverse'.
5Anthropomorphism is when an inanimate object or non-sentient organism is spoken of as though it has human experience, desires and so forth. The atom needs another electron. The virus tries to hide in the tissue.
Many examples of anthropomorphism are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
Teleology is about having a purpose or goal. Much of the functioning of living things seems purposeful (we can suggestion functions to the heart or to the gene as though they are working towards some outcomes, rather than having evolved to be like they are by natural selection). The idea of a well tuned universe could imply some ultimate goal (e.g., to be suitable for life to evolve) which is only achieved when the cosmic numbers Rees discusses have the 'right' values.
6 I am not here excluding the possibility that there may be a creator who has deliberately set up the system, but science is only concerned with natural mechanisms, not ultimate causes. The star has no purpose or intention – it makes heavier elements simply because that is what happens to that material under those conditions.
7 Some of the habits of mind we take for granted are acquired through the culture. For example, people with a formal academic education tend to readily appreciate the form of syllogism and how it is used. But this is something we learn from culture:
fluency in using syllogism depends upon experience that is acquired through education;
people in some traditional cultures have not received the formal education that introduces, and offers experience of thinking with, syllogisms;
therefore people from such cultures will not tend to show fluency in using syllogism.
At least this was what the Russian psychologist Alexander Luria (1976) found when he did field work among traditional cultures just being introduced (indoctrinated?) into the collectivism of the Soviet Union.
8 Of course, as our Universe is by definition all we can directly know, it could only be speculation about whether a universe could in a sense reproduce. Such speculations exist. For example an expanding universe may slow, and contract, till eventually passing through a 'big crunch' back into a singularity – which some think could rebound into a new 'big bang', perhaps with a resetting of the laws and constants of nature. There is also speculation about the singularities at the 'heart' of black holes.
At one time the galaxy (that is, the milky way, our galaxy) was seen as synonymous with the Universe. The discovery that there was other galaxies at vast distances form our own led to seeing them as other universes: each galaxy an 'island' in the immensity of intergalactic space. Now it is commonly suggested there may be other universes (many with their own vast numbers of distinct galaxies) beside our own.
9 In teaching it is usually better to use simile so that the figurative nature of terms is marked (a 'well tuned' universe), unlike in a metaphor (a well tuned universe). One common textual feature is for a term to be introduced as a simile, perhaps by putting it in square quotes, or making it clear it is only 'like' the thing being discussed; but then moving to use the term metaphorically.
In one example I read of a part of a plant being described as like a boat, but then a few paragraphs later this was referred to as the boat without being marked as a simile. A reader has to recognise the term boat is still being used figuratively. This kind of metaphoricalcreep (or metaphorical encroachment perhaps?) could be problematic if a reader forgets a simile was being used, or only starts reading after if has been introduced and marked as being a comparison.
It is something of a cliché, so it was not the phrase itself ("…that's my theory anyway and I'm sticking to it") that caught my attention, but that I heard it used by a scientist.
why, when I put a duvet cover in the washing machine with other items, they all end up inside the duvet cover when the programme finishes
Now this is a phenomenon I have observed myself, and I was not sure of the explanation. As it happened, Dr Sarchet had also wondered about this, indeed she had apparently "thought about this on a weekly basis for as long as I can remember", and had a – well let me say for the moment – suggestion.
"what might be going on here is, obviously when you've got a duvet cover and if you have not sort of buttoned it up before putting it in the wash, you've got a very wide opening, so that's easy statistically for things to enter it, and then as it twists around in the wash, it's actually harder to leave. So, what you've got is kind of a difficulty gradient, things are more likely to go in than they are to come out; and my reckoning is if that keeps happening for a long enough period, enough cycles, eventually everything ends up inside."
Now, I tried to visualise this, and was not convinced. In my mental simulation, the configuration of the duvet cover is such that:
initially, ingress and egress are both readily possible; then,
as twisting begins, possible but less readily; then,
when the duvet becomes very twisted, both ingress and egress are blocked.
There seems to be a 'difficulty gradient' over time, but in my mind this seemed symmetrical in relation to the direction of passage – moving in and out of the duvet cover. Perhaps some items will enter the duvet before the passage is closed – but why should this be all of them, if items can leave as well as enter up to that point?
I am not sure I am right here because I might just be lacking sufficient creative simulation capacity (imagination), or I may not have fully appreciated the mechanism being suggested. After all, a communicator has a meaning in mind, but the text produced (what they say or write, etc.) only represents that meaning and does not inherently contain it. It is up to the audience to make good sense of it. Perhaps I failed. After all, the phenomenon seems to be a real one, so something is going on.
An insight (Image of woman with washing by Amine Tadri, Image of lamp by GraphicsSC from Pixabay)
Analogy in scientific discovery
But what intrigued me about the suggestion was less its veracity, but rather two features of how it was presented. As my heading suggests, Dr Sarchet closed here proposal with the statement that "that's my theory anyway and I'm sticking to it". She prefaced her proposal by reporting on its origin:
"I'd like to argue this might be a little bit like cell biology…"
Dr Sarchet is a biologist, with her doctorate in development genetics, and I thought it was interesting that she was making sense of washing dynamics in terms of cells. Interesting, but not strange: we all seek to make sense of things, and to do so we draw on the range of interpretive resources we have available – the knowledge and understanding, language, images, experiences, and so forth that we carry around represented in our heads. That a biologist might derive a suggestion from a biological source therefore seems quite natural.
Moreover, the process operating is one that is common in science itself. The process I refer to is that of analogy,
"the reason I kind of try to claim that's like cell biology is sometimes, certain substance, it is much easier for them to get into the cell, through the cell membrane because of the way it is made than it is for them to randomly diffuse out again. And that's a really sort of clever, not kind of actively driven way, of creating order"
I have written a lot about analogy on this site, but mostly in relation to science teaching and science communication more widely. That is, how teachers 'make the unfamiliar familiar' by suggesting that some abstract notion to be learnt is actually, in some way, just like something the learners are already familiar and quite comfortable with – it is like a ladder, or the high jump, or the way people arrange themselves sitting on a bus, or like water passing through a drain hole, or whatever.
However analogy is also actually used within scientific practice itself, in the discovery process. Perhaps we should not be surprised then that analogies are often found when scientists talk or write about their work, as well as commonly being used by journalists and authors of popular science books.
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
Sometimes the use of analogy within science itself may be making such small jumps that we may not notice analogy is being used:
Element X is in the same group of the periodic table as element Y, and element Y forms a compound with element A with the properties I am interested in, so I wonder if element X also forms a compound with element A with those properties?
Sometimes however, the jumps are across topics or even sciences.
Does this strange new property of the atomic nucleus suggest the nucleus can behave a bit like a drop of liquid; and, if so, can ideas from the physics of fluids be useful in this different area of nuclear physics?
In this way, the recognition of a potential analogy suggests conjectures that can be tested. Use of such analogies is therefore part of the creative aspect of science.
Perhaps the ultimate use of analogy occurs in physics where equations are found to transfer from one context to another with the right substitutions (e.g., 'it's a wave phenomenon, so we can apply this set of equations that work for all wave phenomena'). As learners will find if they continue with physics as an elective school subject:
We have an equation for the flow of charge in an electrical conductor, and fluid flows, so the same basic equation could work there. And we talk of heat flow, so we should be able to adopt the same basic equation…
I once designed a teaching activity for upper secondary learners (Taber, 2011a) based about the ways certain phenomena are analogous in the sense of following exponential decays (e.g., capacity discharge, radioactive decay, cooling…). For learners not yet introduced to the exponential decay equation this analogy can be built upon the common feature of a negative feedback loop where the magnitude of a driver (excess temperature, radioactive material, p.d.) is reduced by the effect it drives (heat, radioactivity, current);
An exponential decay occurs when a negative feedback loop operates.
In capacitor discharge, A could be p.d. across capacitor, and B current (+ indicates the more p.d. across the plates, the more current flows; – indicates the more current flows {removing charge from the plates}, the lower the p.d. across the plates).
As p.d. falls, the current falls (and so the rate of drop of charge across plates fall) and so the rate of p.d. dropping also falls. …
Similar arguments apply to radioactivity and amount of radioactive material; and cooling and excess temperature.
Progress in science relies on empirical studies to test ideas: but empirical tests can only be carried out afteran act of creative imagination has produced a hypothesis to test. Because science is rightly seen as rational and logical, we can easily lose sight of the creative aspect:
"Creativity is certainly a central part of science, and indeed part of the expectation of the major qualification for any researcher, the Ph.D. degree, is that work should be original. Originality in this context, means offering something that is new to the literature in the field concerned. The originality may be of various kinds: applying existing ideas in a novel context; developing new instrumentation or analytical techniques; offering a new synthesis of disparate literature and so forth. However, the key is there needs to be some novelty. Arthur Koestler argued that science, art, and humour, all relied on the same creative processes of bringing together previously unrelated ideas into a new juxtaposition."
Science teaching needs to reflect how science is creative and so open to speculative divergent thought (as well as being logical and needing disciplined convergent thinking!)
"Science teachers need to celebrate the creative aspects of science – the context of discovery. They should emphasise
how scientific models are thinking tools created by scientists for exploring our understanding of phenomena;
how teaching models are speculative attempts to 'make the unfamiliar familiar' by suggesting that 'in some ways it's a bit like something you already know about'; and in particular
how scientists always have to trust imagination as a source of ideas that may lead to discovery.
However, it is equally important that the creative act is always tempered by critical reflection. Scientific models have limitations; teaching models and analogies may be misleading; and all of us have to select carefully from among the many imaginative possibilities we can generate if we seek ideas that help us understand rather than just fantasise."
But the other point I noted, which I raised at the beginning of this piece, was how Dr Sarchet signed off "…that's my theory anyway and I'm sticking to it" which from a scientific perspective seemed problematic at two levels.
I am not being critical of Dr Sarchet as she was just using a chiché in a humorous vein, and I am sure was not expecting to be taken seriously. Other scientists listening to the programme will have surely realised that. I am not so sure if lay people, or school age learners, will have picked up on the humour though.
As a scientist, Dr Sarchet would, I am sure, acknowledge the provisional nature of scientific knowledge: all our theories are open to being replaced if new evidence or new ways of understanding the evidence suggest they are inadequate. Scientists, being human, do get attached to their 'pet' theories, but a good scientist should be prepared to give up an idea and move on when this is indicated. Scientists should not 'stick to' a theory come what may. Just as well, or we would still be operating with phlogiston, caloric and the aether.
But in any case, I am not convinced that Dr Sarchet had a theory here. A theory is more than an isolated idea – a theory is usually more extensive, a framework connecting related concepts, perhaps encompassing one or more empiricalgeneralisations (laws), and being supported by a body of evidence.
What Dr Sarchet had was a conjecture or hypothesis that she had not yet tested. Certainly having a testable hypothesis is an important starting point for developing a theory – but it is not sufficient.
The hypothesis of continental drift was proposed decades before sufficient investigations and evidence led to the modern theory of tectonics. This is the general situation: the hypothesis or conjecture is a critical step, but by itself does not lead to new knowledge.
Common conceptions of scientific theories
I do not imagine Dr Sarchet really considered her suggestion had reached theory status either. Again, she was just using a common expression. But this is just one example of how words that have precise technical meanings in science (element, energy, force, momentum, plant, substance…) are used with more flexible and fluid meanings in everyday life.
For most people, a 'theory' (let me denote this theorylifeworld to mean how the word is used in everyday discourse) is nothing special – we all have theorieslifeworld all the time. Perhaps a theorylifeworld that a particular football team will win on Saturday, or that next door's cat hates you, or that they are putting less biscuits in these packets than they used to. A theorylifeworld can be produced with little effort, held with various degrees of commitment (often quickly forgotten when experience does not fit, but sometimes 'stuck to' regardless!) and often abandoned with little cost.
Now scientific theories are not like that. In one curriculum context, theoriesscience were defined as 'consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world'. But, if learners come to class having long heard and used the term 'theory' with its 'lifeworld' (that is, everyday, informal) meaning then they think they already know what a theory is (and it is not a consistent, comprehensive, coherent and extensively evidenced source of explanations of aspects of the natural world!)
This is not just speculation, as studies have asked school age learners how they understand such terms. One study, undertaken in that curriculum context that suggested theories are 'consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world' found most respondents had quite a different idea (Taber, et al., 2015). They generally saw a theory as something a scientist made up effortlessly (almost on a whim). Accordingly, they did not think that theories had a very high status – as they had not yet been tested in any way. Once tested, any 'theory' that passed the test ceased to be a theory – perhaps becoming a law: something seen as proven and having (unlike the theory) high epistemological status.
This common pattern is caricatured in the figure:
From Taber et al., 2015
So, laws were seen as of higher status than theories. Laws were proven and so not open to questioning (that is, their conjectural nature as generalisations that could never be proven were not recognised), whereas theories were little more than the romanced flotsam and jetsam of someone's imagination.
It is just a theory
Now of course, I am generalising here from a small sample (of 13-14 year olds learners from a few schools in one country) and individual learners have their own nuanced understandings – aligned to the curriculum account to different degrees.
One interviewed learner confused theories with theorems from mathematics . But, as a generalisation, the learners interviewed tended to see a theory much more as a hypotheses or conjecture than as a worked through conceptual framework of related ideas that are usually supported by a range of evidence, often collected by deliberate testing.
This is useful for the teacher to bear in mind as clearly when the teacher refers to theory, the learners will often understand this as something quite different from what was intended. Probably the only response to this is to review the intended meaning of 'scientific theory' each time one is discussed. Learners can overcome their alternative conceptions with sufficient support and engagement, but the teacher has to work hard when the existing idea is not only long-established but also being reinforced by everyday discourse (and scientists in the media such as Dr Sarchet shifting to the vernacular, as non-scientists may not recognise the transition from a technical to an everyday code).
So, for example , the theory of natural selection (or general relativity if you prefer), is not proven because in science we can never prove general ideas, and so it is just a theory. But theories are all we are ever going to get in science (for certainties look elsewhere), and some of them are so well tested and supported that in practice we treat them as secure and almost as if certain knowledge.
Perhaps it does not matter enormously if many learners leave school thinking general relativity is only a theorylifeworld. Perhaps it does not even matter that much for many learners if they leave school thinking natural selection is only a theorylifeworld. But when people dismiss climate change or the basis of vaccination as 'just a theory' this is much more problematic, as it invites an attitude that these 'consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world' are of no more merit than your neighbour's 'theory' about the next set of winning lottery numbers or a politician's 'theory' about the merits of high import tariffs for reducing the price of eggs. And that is a problem, as climate change and vaccination really matter – critical to individual and collective survival.
At least, that's my theory, and I'm sticking to it.
Of undead trees, silent genes and chaperone proteins
Keith S. Taber
These zombie metaphors become (like a neutron star) 'undead' as they pass from the expert's text to the novice's mind. They are phantom metaphors in the sense that they will manifest as 'living' metaphors to the uninitiated even though the expert user knows they have been put to death.
…the novice or non-specialist has no way of knowing what is the refined meaning and what is just semantic residue.
I have become a little obsessed with the figurative language used to explain science. Science often involves quite abstract ideas, which – by definition, being abstract – do not directly relate to familiar concrete objects and experiences. Learning theory suggests that to make good sense of new information, we need to relate it existing mental resources (existing knowledge and understanding; familiar experiences or images, and so forth).
This implies a paradox (indeed this is related to a traditional puzzle known as 'the learning paradox'):
we can only make sense of things we can relate to in terms of past experience
the science curriculum sets out a large number of abstract ideas that do not directly relate to the everyday experience of most people
We are all familiar with green plants, and may know from practical experience that they need light and moisture, but that direct everyday, phenomenal, experience is some way from the abstractconcept of photosynthesis. This point could be repeated regarding any number of other ideas met in science courses: magnetic hysteresis, p-orbitals, electron spin, genomes, metabolism, uniform electrical fields, electronegativity…
Now, perhaps any science teachers or scientists who read that passage may feel I am exaggerating – they can no doubt readily bring to mind images representing hysteresis and fields and genomes, and equations for photosynthesis with chemical formulae, and the values electron spin can take (±1/2, obviously). These things will be familiar and can be readily represented in 'working memory' (where we undertake deliberate thinking), so to be applied or mentipulated in various ways. But that is a result of the familiarity of expertise built up over a good deal of time. Sure, I can bring to mind a representation of a double bond or a methane molecule or the earth's magnetic field as easily as I can bring to mind an image of a table or a bus or a blackbird. This is useful for a science educator, but is also a potential barrier to putting oneself in the place of a novice learner.
A key is that "the science curriculum sets out a large number of abstract ideas that do not directly relate to the everyday experience of most people". And teachers, and other science communicators (such as journalists and science writers) can address this in two ways.
The best response, when possible, is to provide experiences (through demonstrations and practical activities) that motivate the concepts to be learnt. By motivate, I mean that this experience provides a recognised need for the explanations (as well as associated technical terminology) to make sense of the experiences. Practical work in science classes can be used in various ways, and rather than teach students about some theory, and then demonstrate it, it may be possible to offer experiences which raise questions and wonderment that will give the explanations 'epistemic relevance' (Taber, 2015). The learner will not just be learning about concept X because it is in a syllabus, but because they want to know why Y happened. Now that may seem idealistic – but most children start curious (perhaps before the routine nature of formal education somewhat dulls this) and it is something to aim for.
But of course some things are too slow, too fast, too big, or too small (or too dangerous or too expensive) to bring into the classroom. One cannot* teach the big bang by giving learners a direct experience which will lead to them asking questions that can be satisfactory answered by introducing the canonical scientific account. (* Perhaps I am wrong – if so, I would like to see ther lesson plan.)
Tools for making the unfamiliar familiar
So, the other approach to 'making the unfamiliar familiar' needs to be indirect, perhaps with videos and simulations and models which represent the inaccessible experiences – supported by (and where those tools are not available, through) a narrative where the teacher talks new entities into existence in a learner's 'mind (Lemke, 1990).
Important tools here are analogies where the learner is told that the unknown 'X' is in some ways a bit like the very familiar 'A'. There are a great many examples of analogies used in explaining science. Here are just a few:
Now analogies (like models more generally) are never perfect. X is like A in some ways, but in other ways X is not at all like A. (Otherwise, an X would be an A, and so no more familiar than what is being introduced.) This imperfect mapping does not matter because the use of analogy is not just (i) saying 'X' is in some ways a bit like 'A', as having established that anchor in the learner's prior experience, the teacher develops the comparison by exploring with the learners (ii) the ways in which the two things are alike and (iii) the ways they are not alike, and so starts to build up the learner's familiarity with the nature and properties of X.
carefully analyse the analogy in advance and be confident that the analogy, and, in particular, the features of the positive analogy that are useful for teaching, are indeed already familiar to learners in the class;
be explicit about the use of the analogy as a tool, a kind of model or device for generating conjectures to think about;
be very explicit about the structural features being mapped across, so it is very clear which features of the analogue are being drawn upon to introduce the target knowledge…
explore aspects of the negative analogy that could mislead learners (perhaps invite learners to consider other features of the analogue and suggest aspects that may or may not transfer);
consider the analogy as part of a scaffolding strategy – an interim support to be withdrawn as soon as it is no longer needed as learners are comfortable with the target concept."
A weaker technique than analogy is simile: simply pointing out that X is like A. This is clearly not going to do the work of an analogy, as when introducing a whole new theoretical concept, but has a role 'in passing' when pointing out some single feature or function.
Simile is widely used in communicating science. There are descriptive similes that tell us that something unfamiliar physically resembles something familiar ('lacework', 'bristle-like', 'like a boat') : this technique was widely used by naturalists in describing things they observed, such as novel species, and was especially valuable before the invention of photography. Contemporary science communicators also commonly make use of this technique with more abstract comparisons to functions and properties rather than just appearance:
Now metaphor is like simile, except that the comparison is implicit. That is, consider the difference between saying:
a mitochondrion is like the engine room of a cell; and
a mitochondrion is the engine room of a cell;
As in the simile, the user does not go on to explain how the mitochondria may be understood in this way (which would constitute an analogy) and so the audience is required to do some work (so similes should only be used in teaching when the teacher is confident meanings are obvious to the learners). But with the metaphor the audience has to first even recognise there is a comparison being made, as this is not explicit. After all,the following two propositions have parallel structures:
'a mitochondrion is the engine room of a cell'
'a headteacher is the professional leader of a school staff'
In one case identity is intended (a headteacher IS the professional leader of a school staff), but in the other case there is only a figurative identity: a mitochondrion is not an engine room (even if that could be the basis of an analogy that could be productively explored). So, I advise teachers to avoid metaphor in their explanations, and to always make it clear they are using a comparison. It may seem obvious that a tiny organelle is not (and cannot be) the same thing as the engine room in a ship; but why add to the learner's task in making sense of teaching by adding the need for an extra stage of interpretation that could be avoided?
Manifold metaphors
That said, metaphors are very common in science communication. Here are just a few examples of many I have collected.
Perhaps we should not be surprised at metaphors being so ubiquitous because metaphor is a core feature of language. They are so commonplace that we do not always consciously notice them, but can often simply read or listen straight past them. Even if we notice there is a metaphor in a text, where it is successful we immediately grasp the meaning and so it aids understanding rather than confounding it. I am hoping that my use of the metaphor 'anchor', above, worked that way. You may have spotted it was a metaphor – but I hope you did not have to stop reading and puzzle out what I meant by it in that context.
An anchor (Image by Tanya from Pixabay) but what has this got to do with meaningful learning?
In particular, language often develops by metaphor. So a term that is used initially as a metaphor, sometimes get taken up and repeated to such an extent that some decades later it is treated as a conventional meaning for a term and no longer considered a metaphor. Thus the language grows. So 'charge', in 'electrical charge', was initially a metaphor, an attempt to describe something new in terms of something already familiar (the charge that needed to be placed in a firearm ready for the next shot) but is not considered so now. Sometimes the 'new' meaning comes to exist alongside the original as a kind of homonym (as separate meanings – as with the word 'bank' when referring to a river bank and a financial institution), and sometimes the original meaning falls out of use (as few people use firearms today, and even fewer charge them with shot and gun powder before use).
So, terms that are at one time metaphorical can become 'literal' over time, and these are sometimes called deadmetaphors. They are also known as historical or frozenmetaphors. The latter term appeals (although it is a metaphor, of course! – words do not actually freeze) because it suggests a change of state that may take some time. That is, there are active metaphors, and frozen metaphors, and then some 'freezing metaphors' that are beginning to be widely understood directly without being understood as figurative, but where this transformation is not yet complete.
I am sure there are plenty of terms that are in common use in the language where, if people were asked, some, but not all, would recognise them as metaphorical (dyingmetaphors? freezingmetaphors?) – and where perhaps decade-on-decade repeat surveys would show some of these had died/frozen, while new metaphors were appearing, becoming widely used, and slowly starting to solidify.
At the risk of pushing an analogy too far, we might note that the state of a sample of a substance depends on the conditions (there are no ice sheets over the Caribbean islands), so if we extend this freezing metaphor, might we find metaphors that have frozen in some environments but are still fluid in other conditions?
Zombie metaphors?
Actually, I think this is likely very common in technical fields like the sciences. I have written here about some of the language used by astronomers when discussing the births, life-cycles and deaths of stars.
Clearly these terms were introduced metaphorically. But now they are treated as if technical terms – so, now, stars really do get born, and really do die because these terms now refer to what actually happens to stars, rather than just to processes that had some similarity to what happened to stars.
I think this is potentially problematic from an educational perspective, as the novice who reads a popular astronomy book or listens to a podcast or hears a news report where stars are said to be born, live out their long lives, and die, is unfamiliar with the astronomical processes labelled in this way, and can only understand these terms metaphorically by reference to how familiar living [sic, non-figuratively living] things are born, live, and die. A pet dog that dies is no longer around, but a large star that 'dies' in a supernova explosion may then live on as a neutron star – a bit like some phoenix that rises from the funeral ashes to be reborn.
Reincarnation? The Crab Nebula as seen by the Hubble Space Telescope (HST). The Nebula is a Supernova Nebula — One formed from a supernova which left a millisecond pulsar at its center. So was the explosion the death of as star – or was it just a transition to a new phase of the star's life cycle?
I am not suggesting that people will be generally confused about heavenly bodies being actually alive (even if for many centuries they were widely assumed to be so – many people seem to have thought stars and planets are living beings like humans), but because – for the experts 'born', 'live', 'die' are no longer metaphors – they may be are used without awareness of how a novice may struggle to fully appreciate their 'technical' implications.
So, in a sense, these metaphors become 'undead' (like the neutron star?) as they pass from the expert's text to the novice's mind. They are phantom metaphors in the sense that they will manifest as 'living' metaphors to the uninitiated even though the expert user knows they have (through habitual use) been put to death.
Not just out of this world…
I suspect that there are zombie metaphors in use not just in astronomy, but in many technical fields. This means that any of us who are reading 'out of specialism' are likely to mistake phantoms for live metaphors even when an author or speaker is using a term non-figuratively with a meaning that has long ago solidified in that specific discourse environment.
When a pure substance freezes it may exclude impurities. So, for example, a sample of sea water will start to freeze, and the ice forming will exclude the salts dissolved in the water (so the salt concentration in the remaining solution increases). When a metaphor freezes to become a technical term it retains the aspect of the comparison that were originally intended figuratively, but not other features that are not relevant – they get 'frozen out' so to speak. The expert has in mind the 'purified' meaning, and does not bring unintended associations to mind. But the non-specialist has no way of knowing what is the refined meaning and what is just semantic residue.
Figuring out erythrocytes…
Consider, for example, a textbook chapter entitled "Anemias, Red Cells, and the Essential Elements of Red Cell Homeostasis" (Benz, 2018). This chapter uses a range of figures of speech to help communicate technical ideas. Some of these can be glossed:
There are also a couple of places where phrasing might be seen to move beyond simple metaphor to anthropomorphism: that is, writing that seems to imply non-sentient entities have preferences and desires or act after conscious deliberation:
The chapter also refers to the proteins known as Ankyrin. This is a technical term of course. A review article relates that
"Ankyrin is a binding protein linking structural proteins of the cytoplasm to spectrin, a protein present in the membrane cytoskeleton in human erythrocytes that functions as an anchoring system to provide resistance to shear stress."
Caputi & Navarra, 2020
Indeed, ankyrin gets it's name from the Greek word for anchor. So ankyrin is not a metaphor, but derives its name metaphorically in relation to its perceived function.
Ribbon diagram of a fragment of the membrane-binding domain of human erythrocytic ankyrin (left-hand image, from Wikipedia commons), member of a class of proteins named after an anchor (right-hand image).
But I also noticed a number of other terms which manifested as metaphors, but which I do not think would be considered metaphors by specialists. In the field, they would be dead metaphors, but to a novice they might appear as phantoms, assumed to be meant metaphorically:
These can seem to be figures of speech, with the fluid quality of offering the reader the creative act of deciding which properties to transfer across from the metaphor/simile: but actually are all widely used terms in the field, and so actually have definite 'frozen' meanings. A vascular tree has branches (and twigs) but no leaves or fruits.
Perhaps there is not too much potential here to confuse readers (especially given the intended readership for this particular text would be professional / graduate), but it does reinforce the idea that communicating science is a challenge when not only, as is often noted, so much of the language of science texts is technical; but a lot of technical terms are dead metaphors: with frozen meanings that have the potential to melt back to life, and invite more fluid interpretations from learners.
Work cited:
Benz, Edward J. (2018) Anemias, red cells, and the essential elements of red cell homeostasis, in Edward J. Benz, Nancy Berliner, & Fred J. Schiffman, Anemia. Pathophysiology, Diagnosis, and Management, Cambridge University Press, 1-13.
Caputi, Achille Patrizio & Navarra, Pierluigi (2020) Beyond antibodies: ankyrins and DARPins. From basic research to drug approval. Current Opinion in Pharmacology, 51, April 2020, pp.93-101.
Lemke, Jay L. (1990) Talking Science: Language, Learning, and Values, Bloomsbury Academic.
Taber, K. S. (2015) Epistemic relevance and learning chemistry in an academic context. In I. Eilks & A. Hofstein (Eds.), Relevant Chemistry Education: From Theory to Practice (pp. 79-100). Sense Publishers. [Download chapter]
Making unfamiliar cultures familiar using scientific concepts
Keith S. Taber
Clifford Geertz may have been a social scientist, but he clearly thought that some abstract ideas about culture, society and politics were best explained using concepts and terminology from the natural sciences.
Clifford Geertz was a social scientist who referenced a goof deal of scientific vocabulary
I first came across the anthropologist Clifford Geertz when teaching research methods to graduate students. Geertz had popularised the notion of the importance of thick description, or rich description, in writing case studies. I acquired his book 'The Interpretation of Cultures' (a collection of his papers and essays) to read more about this. I found Geertz was an engaging and often entertaining author.
"Getting caught, or almost caught, in a vice raid is perhaps not a very generalisable recipe for achieving that mysterious necessity of anthropological field work, rapport, but for me it worked very well."
(From 'Deep play: notes on the Balinese cockfight')
Anthropology: A rather different kind of science – largely based on case studies.
Generalisation in natural science
Case studies are very important in social sciences, in a way that does not really get reflected in natural science.
It has long been recognised that in subjects such as chemistry and physics we can often generalise from a very modest number of specimens. So, any sample of pure water at atmospheric pressure will boil around 100˚C.1 All crystals of NaCl have the same cubic structure. All steel wires will stretch when loaded. And so on. Clearly scientists have not examined, say, all the NaCl crystals that have ever formed in the universe, and indeed have only actually ever examined a tiny fraction, in one local area (universally speaking), over a short time period (cosmologically, or even geologically, speaking) so such claims are actually generalisationssupported by theoretical assumptions. Our theories give us good reasons to think we understand how and why salt crystals form, and so how the same salt (e.g., NaCl) will always form the same type of crystal.2
Even in biology, where the key foci of interest, organisms, are immensely more complex than salt crystals or steel wires, generalisation is, despite Darwin 3, widespread:
"We might imagine a natural scientist, a logician, and a sceptical philosopher, visiting the local pond. The scientist might proclaim,
"see that frog there, if we were to dissect the poor creature, we would find it has a heart".
The logician might suggest that the scientist cannot be certain of this as she is basing her claim on an inductive process that is logically insecure. Certainly, every frog that has ever been examined sufficiently to determine its internal structure has been found to have a heart, but given that many frogs, indeed the vast majority, have never been specifically examined in this regard, it is not possible to know for certain that such a generalisation is valid. (The sceptic, is unable to arbitrate as he simply refuses to acknowledge that he knows there is a frog present, or indeed that he can be sure he is out walking with colleagues who are discussing one, rather than perhaps simply dreaming about the whole episode.)
…I imagine most readers are still siding with the scientist's claim. So, can we be confident this particular frog has a heart, without ourselves being heartless enough to cut it open to see?
Strictly, in an absolute sense, we cannot know for certain the entity identified as a frog has a heart. After all,
perhaps it is a visiting alien from another solar system that looks superficially like our frogs but has very different anatomy;
perhaps it is a mechanical automaton disguised as a frog, that is covertly collecting intelligence data for a foreign power;
perhaps it is a perfectly convincing holographic image of a 'late' frog that, since being imaged, was eaten by a predator;
perhaps other logically possible but barely feasible options come to mind?
But if it really is a living (Terran) frog, then we know enough about vertebrate evolution, anatomy and physiology, to be as near to certain it has a functioning heart as we could be certain of just about anything. 4
Generalisation in social science
Often, however, this type of generalisation simply does not work in social science contexts. If we find that a particular specimen of gorilla has seven cervical vertebrae then we can probably assume: so do other gorillas. But if we find that one school has 26 teachers, we clearly cannot assume this will apply to the next school we look at. Similarly, the examination results and truancy levels will vary greatly between schools. If we find one 14 year old learner thinks that plants only respire during the night time, then it is useful to keep this in mind when working with other students, but we cannot simply assume they will also think this.
The distinction here is not absolute, as clearly there are many things that vary between specimens of the same species, which is why many biological studies use large samples and statistics. In general [sic], generalisation gets more problematic as we shift from physical sciences through life sciences to social sciences. And this is partially why case study is so common within the social sciences.
The point is that the assumption that we can usually safely generalise from one NaCl crystal to another, but not from one biology teacher to another, is based on theoretical considerations that tell us why the shape (but not the mass or temperature) of a crystal transfers from one specimen of a substance to another, but why the teaching style or subject knowledge of one teacher depends on so many factors that it cannot be assumed to transfer to other teachers.
Drawing upon both a quotidian comparison and a scientific simile, Geertz warned against seeing "a remote locality as the world in a teacup or as the sociological equivalent of a cloud chamber".
A case study examines in depth one instance from among many instances of that kind: one teacher's teaching of entropy; one school's schemes of work for lower secondary science; one learner's understanding of photosynthesis; the examples, similes and analogies used in one textbook; …
Case studies look at a single instance (e.g., one school, one classroom, one lesson, one teaching episode) in great detail. Case studies are used when studying complex phenomena that are embedded in their context and so have to be studied in situ. You can study a crystal in the lab. You can also study extract cells from an organism and look at them in a Petri dish – but those isolated cells in vitro will only tell you so much about how they normally function in vivo within the original tissue.
Similarly, if you move a teacher and her class out of their normal classroom embedded in a particular school in order to to study a lesson in a special teaching laboratory in a research institution set up with many cameras and microphones, you cannot assume you will see the lesson that would have taken place in the normal context. Case studies therefore need to be 'naturalisic' (carried out in their usual context) rather than involving deliberate researcher manipulation. Geertz rejected the description of the field research site as a natural laboratory, reasonably asking "what kind of laboratory is it where none of the parameters are manipulatable?"
When I worked in further education I recall an inspection where one colleague told us that the external inspector had found her way to her classroom late, after the lesson had already started, and so asked the teacher to start the lesson again. This would have enabled the inspector to see the teacher and class act out the start of the lesson, but clearly she could not observe an authentic teaching episode in those circumstances.
Case study is clearly a sensible strategy when he have a particular interest in the specific case (why do this teacher's students gets such amazing examination results?; why does this school have virtually zero truancy rates?), but is of itself a very limited way of learning about the general situation. We learn about the general by a dual track (and often iterative) process where we use both surveys to find out about typicality, and case studies to understand processes and to identify the questions it is useful to include in surveys.
If case studies are to be useful, they need to offer a detailed account (that 'thick description') of the case, including its context: so to understand something about an observed lesson it may be useful to know about the teacher's experience and qualifications; about the school demographic statistics and ethos; about the curriculum being followed, and other policies in place; and so forth.
As one example, to understand why a science teacher does not challenge a student's clear misconceptions about natural selection (is the teacher not paying attention, or not motivated, or herself ignorant of the science?), it may sometimes be important to know something about the local community and and administrative practices. In the UK, a state school teacher (who is legally protected from arbitrary, capricious or disproportionate disciplinary action) is not going to get in trouble for explaining science that is prescribed in the curriculum, even if some parents do not like what is taught; but that may not be true in a very different context where the local population largely holds fundamentalist, anti-science, views, and can put direct pressure on school leaders to fire staff.
Beware of unjustified generalisation
This use of 'thick description' provides the context for a reader to better understand the case. However, no matter how detailed a case study is, and regardless of the insight it offers into that case, a single case by itself never provides the grounds for generalisation beyond the case. It can certainly offer useful hypotheses to be tested in other cases – but not safe conclusions!
Geertz was an anthropologist who knew that much field work involves specific researchers (with their idiosyncraticinterpretive resources – background knowledge, past experiences, perspectives, beliefs, etc. -and individual personalities and inter-personal skills) spending extended periods of time in very specific contexts – this village, that town, this monastery, that ministry… The investigators were not just meant to observe and record, but also to look to make sense of (and so interpret) the cultures they were immersed in – but this invites over-generalisation. Geertz warns his readers of this at one point,
"I want to do two things which are quintessentially anthropological: to discuss a curious case from a distant land; and to draw from that case some conclusions of fact and method more far-reaching than any such isolated example can possibly sustain."
(From: 'Politics past, politics present: some notes on the uses of anthropology in understanding the new states')
Using science to make the unfamiliar familiar
One of the features of Geertz's writings that I found interesting was his use of scientific notions. Often on this site I have referred to the role of the teacher in 'making the unfamiliar familiar' and suggested that science communicators (such as teachers, but also journalists, authors of popular science books and so forth) seek to make abstract scientific ideas familiar for their audience by comparing them with something assumed to already be very familiar. As when Geertz suggests that the 'human brain resembles the cabbage'. I have also argued that whilst this may be a very powerful initial teaching move, it needs to be just a first step, or learners are sometimes left with new misconceptions of the science.
For a science teacher, the scientific idea is thetarget knowledge to be introduced, and a comparison with something familiar is sought which offers a useful analogue. I list myriad examples on this site – some being science teachers' stock comparisons, some being more original and creative, and indeed some which are perhaps quite obscure. Here are just a few examples:
But this can be flipped when the audience has a strong science knowledge, and so a scientific phenomenon or notion can be used to introduce something less familiar. (As one example, the limited capacity of working memory and the idea of 'chunking' may be introduced by comparison with different triglycerides: see How fat is your memory? A chemical analogy for working memory. But this is only useful if the audience already knows about the basic structure of triglycerides.)
Geertz may have been a social scientist, but he clearly assumed some abstract ideas about culture, society and politics were best explained using concepts and terminology from the natural sciences. So, for example, he made the argument for case study approaches in research,
"The notion that unless a cultural phenomenon is empirically universal it cannot reflect anything about the nature of man is about as logical as the notion that because sickle-cell anaemia is, fortunately, not universal, it cannot tell us anything about human genetic processes. It is not whether phenomena are empirically common that it is critical in science – else why should Becquerel have been so interested in the peculiar behaviour of uranium? – but whether they can be made to reveal the enduring natural processes that underlie them. Seeing heaven in a grain of sand 5 is not a trick that only poets can accomplish."
(From: 'The impact of the concept of culture on the concept of man')
Geertz was also aware of another failing that I have seen many novice (and some experienced) researchers fall into. In education, as in anthropology, we often rely on research participants as informants, but we have to be careful not to confuse what they tell us with direct observations:
'the teacher is careful to involve all learners in the class in answering questions and classroom discussion' (when it should be: the teacher reports that he is careful to involve all learners in the class in answering questions and classroom discussion )
'the learner was very good at using mathematics in physics lessons' (when it should be: the learner thought that she very good at using mathematics in physics lessons.
'the school had a highly qualified, and select group of teachers who were all enthusiastic subject experts' (or so the headteacher told me).
If such slips seem rather amateur affairs, it is not uncommon to see participant ratings mis-described: so a statements like '58% of the teachers were highly confident in using the internet in the classroom' may be based on participants responding to a scale item on a questionnaire (asking 'How confident are you…') where 58% of respondents selected the 'highly confident' rating.
So, actually '58% of the teachers rated themselves as highly confident in using the internet in the classroom'. For these two things to be equivalent we have to ourselves be 'highly confident' in a number of regards – some more likely than others. Here are some that come to mind:
the teachers took the questionnaire seriously, and did not just tick boxes arbitrarily to complete the activity quickly (I am sure none of us have ever done that 😎);
the teachers read the question carefully, and ticked the box associated with their genuine rating (i.e., did not tick the wrong box by mistake, perhaps misaligning response boxes for a different item);
the teachers understood and shared the researcher's intended meaning of the item (e.g., researcher and responder mean the same thing by 'confidence in using the internet in the classroom');
the teachers had a stable level of confidence such that a rating reflected more than their feeling at that moment in time (perhaps after an especially successful, or fraught, lesson);
a teacher's assessment of confidence clearly fitted with one of the available response options (here, highly confident – perhaps the only options presented to be selected from were 'highly competent'; 'neither professionally competent nor incompetent'; 'completely hopeless');
the teachers were open and honest about their responses (so, not influenced by how the researcher might perceive them, or who else might gain access to the data and for what purpose);
the teacher was a good judge of their own level of confidence (and does not come from a cultural context where it would be shameful to boast, or where exaggeration is expected).
As scientists we tend to come to rely on instrumentation even though it is fallible. We may report distances and temperatures and so forth without feeling we need to add a caveat such as "according to the thermometer" each time. 6 But instrumentation in social science tends to be subject to more complications. Geertz realised that in his field there was commonly the equivalent of writing that '58% of the teachers were highly confident in using the internet in the classroom' when the data only told us '58% of the teachers rated themselves as highly confident in using the internet in the classroom':
"In finished anthropological writings, including those collected here, this fact – that what we call our data are really our own constructions of other people's construction of what they and their compatriots are up to – is obscured because most of what we need to comprehend a particular vent, ritual, custom, idea, or whatever is insinuated as background information before the thing itself is is directly examined."
(From 'Thick description: toward an interpretative theory of culture.')
Some scientific comparisons
In discussing a teknonymous system of reference – where someone who had been named Joe at birth but who is now the father of Bert, is commonly known as 'Father of Bert' rather than Joe; at least until Bert and Bertha bring forth Susie (and take on new names themselves accordingly), at which point Joe/Father of Bert is then henceforth referred to as 'Grandfather of Susie' – Geertz suggests what "looks like a celebration of a temporal process is in fact a celebration of the maintenance of what, borrowing a term from physics, Grgory Batesaon has aptly called 'steady state'." This is best seen as a simile, as the figurative use of the term 'steady state' is clearly marked (both by the 'scare quotes' and the acknowledgement of the borrowing of the term).
Many of Geertz's figures of speech are metaphors where the comparison being used is not explicitly marked (so the state capital 'was' the nucleus). Another 'doubly marked' simile (by scare quotes and the phrase 'so to speak') concerned the idea of a centre of gravity:
"The two betting systems, though formally incongruent, are not really contradictory to one another, but are part of a single larger system, in which the centre bet is, so to speak, the 'centre of gravity', drawing , the larger it is the more so, the outside bets toward the short-odds end of the scale."
(From 'Deep play: notes on the Balinese cockfight')
Among the examples of Geertz using scientific concepts as the 'familiar' to introduce ideas to his readers that I spotted were:
Not all of these examples seemed to be entirely coherent, or strictly aligned with the technical concept. Geertz was using the ideas as figures of speech, relying on the way a general readership might understand them. Although, in some of these cases I wonder how familiar his readership might be with the scientific idea. We can only 'make the unfamiliar familiar' by comparing what is currently unfamiliar with what is – already – familiar.
Making the unfamiliar familiar, by using something else unfamiliar?
My general argument on this site has been that if the comparison being referred to is not already familiar to an audience, then it cannot help explain the target concept – unless the unfamiliar comparison is first itself explained; which would seem to make it self-defeating as a teaching move.
However, while I think this is generally true, I can see possible exceptions.
One scenario might be where the target idea is seen as so abstract, that the teacher or author feels it is worth first introducing, and explaining, a more concrete or visualisable comparison as a potential stepping stone to the target concept.
Another scenario might be where the teacher or author has a comparison which is considered especially memorable (perhaps controversial or risque, or a vivid or bizarre image), and so again thinks the indirect route to the target concept may be effective (or, at least, entertaining).
There might also be an argument, at least with some audiences, that because using a comparison makes the (engaged) reader process the comparison it aids understanding and later recall even when it needs to be explained before it will work as a comparison.
So, for example, typical readers of anthropology reports may know little about the neural organisation of cephalopods, but when being told that "the octopus, whose tentacles are in large part separately integrated, neurally quite poorly connected with one another and with what in the octopus passes for a brain … nonetheless manages…to get around…", perhaps this elicits reflection on how being an octopus must be such a different experience to being human, such that the reader pauses for thought, and then (while imagining the octopus moving around without a"smoothly coordinated synergy of parts" but rather "by disjointed movements of this part, then that") pays particular attention to how this offers a "appropriate image [for] cultural organisation".
These are tentacled, sorry, tentative suggestions, and I would imagine they all sometimes apply – but empirical evidence is needed to test out their range of effectiveness. Perhaps this kind of work has been done (I do not recall seeing any studies) but, if not, it should perhaps be part of a research programme exploring the effectiveness of such devices (similes, metaphors, analogies, etc.) in relation to their dimensions and characteristics, modes of presentation, and particular kinds of audiences (Taber, 2025).
Some of Geertz's references could certainly be seen as fitting the wider zeitgeist – references to DNA with its double helix may be seen to tap into a common cultural motif:
"So far as culture patterns, that is, systems or complexes of symbols, are concerned…that they are extrinsic sources of information. By 'extrinsic', I mean only that – unlike genes for example – they lie outside the boundaries of the individual organism …By 'source of information', I mean only that – like genes – they provide a blueprint of template in terms of which processes external to themselves can be given a definite form. As the order of bases in a strand of DNA forms a coded program, a set of instructions, or a recipe, for the synthesis of the structurally complex proteins which shape organic functioning, so culture patterns provide such programmes for the institution of the social and psychological processes which shape human behavior …this comparison of gene and symbol is more than a strained analogy …
"Symbol systems…are to the process of social life as a computer's program is to its operations, the genic helix to the development of the organism…
There is a sense in which a computer's program is an outcome of prior developments in the technology of computing, a particular helix of phylogenetic history…But …one can, in principle anyhow, write out the program, isolate the helix…"
(From 'Religion as a cultural system' and 'After the revolution: The fate of nationalism in the new states')
Geertz also goes beyond simply offering metaphors, as in this extract from an essay review of the classic structuralist anthropology text with a title normally rendered into English as 'The Savage Mind':
"That Lévi-Strauss should have been able to transmute the romantic passions of Tristes Tropiques into the hypermodern intellectualism of La Pense Sauvage is surely a startling achievement. But there remain the questions one cannot help but ask. Is this transmutation science or alchemy? Is the 'very simple transformation' which produced a general theory out of a persona disappointment real or a sleight of hand? Is it a genuine demolition of the walls which seem to separate mind from mind by showing that the walls are surface structures only, or is it an elaborately disguised evasion necessitated by a failure to breach them when they were directly encountered?"
(From 'The cerebral savage: on the work of Claude Lévi-Strauss')
It is worth noting here that whenever a work is translated from one language to another, there is an interpretive process, as many words do not have direct equivalents (covering precisely the same scope or range, with exactly the same nuances) in other languages. 'Savage' in English suggests (to me at least) aggression, and an association with violence. The French original 'sauvage' could be translated instead as 'wild' or 'untamed' which do not necessarily have the same negative associations. This is why when educational, and other social, research is reported in a language other than that in which data was collected, it is important for investigators to report this, and explain how the authenticity of translation was tested (Taber, 2018).
This device of an extended metaphor, where a comparison is not just mentioned at one point but threaded through a passage, can approach analogy – but without the explicit mapping of analogue-to-target expected in a formal teaching analogy. Here the idea of a property of meaning is compared with physical or chemical properties, but without the techniques the scientist has to identify and quantify such properties:
"And so we hear cultural integration spoken of as a harmony of meaning, cultural change as an instability of meaning, and cultural conflict as an incongruity of meaning, with the implication that the harmony, the instability, or the incongruity are properties of meaning itself, as, say, sweetness is a property of sugar or brittleness of glass.
Yet, when we try to treat these properties as we would sweetness or brittleness, they fail to behave, 'logically', in the expected way. When we look for the constituents of the harmony, the instability, or the incongruity, we are unable to find them resident in that of which they are presumably properties. One cannot run symbolic forms through some sort of cultural assay to discover their harmony content, their stability ratio, or their index of incongruity; one can only look and see if the forms in question are in fact coexisting, changing, or interfering with one another in some way or other, which is like tasting sugar to see if it is sweet or dropping a glass to see if it is brittle, not like investigating the chemical composition of sugar or the physical structure of glass."
"But, details aside, the point is that there swirl around the emerging governmental institutions of the new states, and the specialised politics they tend to support, a whole host of self-reinforcing whirlpools of primordial discontent, and that the parapolitical maelstrom is a great part an outcome – to continue the metaphor, a backwash – of that process of political development itself."
(From 'The integrative revolution: The primordial sentiments and civil politics in the new states')
Offering manifold comparisons
Sometimes Geertz offers several alternative comparisons for his readers: so, above, the genetic helix is offered in parallel with a computer program, a blueprint for building a bridge, the score of a musical performance, and a recipe for cake. Another example might be:
"The second law of thermodynamics, or
the principle of natural selection, or
the production of unconscious motivation, or
the organisation of the means of production
does not explain everything, not even everything human, but it still explains something; and our attention shifts to isolating just what that something is, to disentangle ourselves from a lot of pseudoscience to which, in the first flush of its celebrity, it has also given rise."
(From 'Thick description: toward an interpretative theory of culture')
There are several ways to explain use of this technique. One is that Geertz is sometimes not confident in his comparisons, so offers alternatives – if one does not 'hit home' with a reader, another might. Perhaps this is about diversity and personalisation – after all, each reader brings their own unique set of interpretive resources (based on their idiosyncratic array of knowledge and experience), so if you do not know about the physics or biology, perhaps you do know about the example from psychology, or economics.
Alternatively, I sometimes got a sense that Geertz was simply enjoying the writing process, and not wanting to censor the creative spark as ideas presented themselves to him. Of course, that is a personal interpretation based on my unique set of interpretive resources: I have also sometimes got the feeling that I am getting carried away with my writing – carried along by the 'flow' experience described by Mihaly Csikszentmihalyi – enjoying my own prose (which at least means that a minimum of one person does), and so possibly at risk of writing too much and consequently boring the reader. Reading Geertz gave me the feeling that he enjoyed the writing process, and that he crafted his writing with a concern for style as well as to communicate information.
From a pedagogic point of view, comparisons (similes, metaphors, analogies) are like models, always imperfect reflections of the target. Greetz suggested that not only was metaphor strictly wrong, but that it could be most effective when most wrong! In teaching it is important to highlight the positive and negative analogy (how this model is like a cell or a star or a molecule, and also how it is not), and that level of explication would be suitable for a textbook; but otherwise could (as well as disrupting style) come across as too didactic. By offering multiple comparisons, each of which are wrong in different ways, perhaps the common target feature can be highlighted?
"To put the matter this way is to engage in a bit of metaphoricalrefocusing of one's own, for it shifts the analysis of cultural forms form an endeavour in general parallel to
dissecting an organism,
diagnosing a symptom,
deciphering a code, or
ordering a system
– the dominant analogies in contemporary anthropology – to one in general parallel with penetrating a literary text."
(From 'Deep play: notes on the Balinese cockfight')
"The meanings that symbols, the material vehicles of thought, embody are often elusive, vague, fluctuating, and convoluted, but they are, in principle, as capable of being discovered through systematic investigation – especially if the people who perceive them will cooperate a little –
as the atomic weight of hydrogen or
the function of the adrenal glands."
(From 'Person, time, and conduct in Bali')
Even if this is not the case; we can expect that if the reader does mental work comparing across the multiple comparisons then this will have brought focal attention to the point being made as the reader passes through the passage of text. (Again, there is a useful theme here for any research programme on the use of figures of speech in science communication: how do readers or listeners process multiple comparisons of this kind, and does this figurative device lead to greater understanding?)
Cultural crystallisation
One recurring image in Geertz's writing is that of crystallisation.
"It is the crystallisation of a direct conflict between primordial and civil sentiments – this 'longing not to belong to any other group' – that gives to the problem variously called tribalism, parochialism, communalism, and so on, a more ominous and deeply threatening quality that most of the other, also very serious and intractable, problems the new states face…
"The actual foci around which such discontent tends to crystallise are various"
"In the one case where [a particular pattern of social organisation] might have crystallised, with the Ashanti in Ghana, the power of the central group seems to have, at least temporarily, been broken."
"The pattern that seems to be developing and perhaps crystallising, is one in which a comprehensive national party…comes almost to comprise the state…"
"…raises the spectre of separatism by superimposing a comprehensive political significance upon those antagonisms, and, particularly when the crystallising ethnic blocs outrun state boundaries…"
(From 'The integrative revolution: The primordial sentiments and civil politics in the new states')
Crystallisation occurs when existing parts (ions, molecules) that are in a fluid (in solution, in the molten state) come together into a unified whole as a result of interactions between the system and its surroundings (evaporation of solvent, thermal radiation). Some of these quoted examples might stand up to being developed as analogies (where features of the social phenomenon can be mapped onto features of the physical change), but when used metaphorically the requirement is simply that there is some sense of parallel.
An interesting question might be whether such metaphors are understood differently by subject experts (here, chemists or mineralogists for example) who may be (consciously or otherwise) looking to map a scientific model onto the author's accounts, rather than a general reader who may have a much less technical notion of 'crystallisation' but might find the reference triggers a strong image?
We might also ask if 'crystallisation' has become something of a dead metaphor: that is, has it been used as a metaphor (a comparison with the change of state) so widely that it has taken on a new general meaning (of little more than things coming together)?
Balanced and unbalanced (social) forces
Another motif that I noticed in Geertz's writing was talking about social/cultural 'forces' as if they were indeed analogous to physical forces. In the following example, the force metaphor is extended:
"In sum, nineteenth century Balinese politics can be seen as stretched taut between two opposing forces; the centripetal one of state ritual and the centrifugal one of state structure."
(From 'Politics past, politics present: some notes on the uses of anthropology in understanding the new states')
The following example also features (as opposed to crystallisation) dissolving,
"In Malaya one of the more effective binding forces that has, so far at least, held Chinese and Malays together in a single state despite the tremendous centrifugal tendencies the racial and cultural differences generates is the fear on the part of either group that should the Federation dissolve they may become a clearly submerged minority in some other political framework: the Malays through the turn of the Chinese to Singapore or China; the Chinese through the turn of the Malays to Indonesia."
(From 'The integrative revolution: The primordial sentiments and civil politics in the new states')
There seems to be another extendedmetaphor here as well, in that following dissolution, there is a danger of becoming submerged in the fluid. This quote also features the notion of 'centrifugal' force, which reappears elsewhere in Geertz's work (see below).
Canonical and alternative conceptions
I associate references to centrifugal force with the common alternative conception that orbiting bodies are subject to balancing forces – a centripetal force that pulls an orbiting body towards the centre, which is balanced or cancelled by a centrifugal force which pulls the object away from the centre. This (incorrect) notion is very common (read about 'Centrifugal force').
From a Newtonian perspective, orbital motion is accelerated motion, which requires a net force – if there was not a centripetal force, then the orbiting body would leave orbit (as, incredibly, happened to the moon in the sci-fi series 'Space: 1999' 7) and move off along a straight line. So, circular motion requires an unbalanced force (at least if we ignore the way mass effects the geometry of space 8).
Martin Landau and Barbara Bain – in 'Space: 1999' (created by Gerry and Sylvia Anderson, produced by ITC Entertainment)
I wondered whether the quote above would be interpreted differently according to a person's level of scientific literacy. Two possible readings are:
"…one of the more effective binding forces…has…held Chinese and Malays together in a single state despite the tremendous centrifugal tendencies…" because the binding forces were stronger than the centrifugal force.
"…one of the more effective binding forces…has…held Chinese and Malays together in a single state despite the tremendous centrifugal tendencies…" because the binding forces balance the centrifugal force.
The implication in the quote is that there is a steady state (if you will pardon the pun), so there must be an equilibrium of forces (that is, option 2). But, this is an area where learners will commonly have alternative conceptions: for example suggesting that gravity must be larger than the reaction force with the floor, or else they would float away; or that in a solid structure the attractive forces between molecules must be greater than the repulsive forces to hold the structure together.
"When [English A level students in a Further Education College] were shown diagrams of stable systems (objects stationary on the ground, or on a table) they did not always recognise that there was an equilibrium of forces acting. Rather, several of the students took the view that the downward force due to gravity was the larger, or only force acting. Two alternative notions were uncovered. One view was that no upward force was needed, as the object was supported instead, or simply that the object could not fall any lower as the ground was in the way. The other view was the downward force had to be greater to hold the object down: if the forces had been balanced there would have been nothing stopping the object from floating away."
Geertz was writing about society, and using the notion of forces metaphorically, but we know that when a learner is led to activate something in memory this reinforces that prior learning. For someone holding this common misconception for static equilibrium (as being due to a larger maintaining force overcoming some smaller force) then reading Geertz's account is likely to lead to:
interpreting the social example in terms of the misconception: binding forces are larger so they hold the state together;
thus rehearsing and reinforcing the prior (mis)understanding of forces!
That is, even though the topic is cultural not physical, and even though Geertz may well have held a perfectly canonical understanding of the physics, his metaphorical language has the potential to reinforce a scientific misconception!
This is not a particular criticism of Geertz: whenever a learner comes across an example that fits their prior conceptions, they are likely to activate that prior knowledge, and so reinforce the prior learning. This is helpful if they have learnt the principles as intended, but can reinforcemisconceptions as well as canonical ideas. References to a scientific phenomenon or principle that assume, and so do not make explicit, the scientific ideas, always risk reinforcing existing misconceptions. (The teacher therefore tends to reiterate the core scientific message each time a previously taught principle is referenced in class – what might be called a 'drip-feed' tactic!)
Geertz seemed to be quite keen on the 'centrifugal' reference:
"It is the Alliance…where the strong centrifugal tendencies, as intense as perhaps any state…"
"the integrative power of a generally mid-eastern urban civilisation against the centrifugal tendencies of tribal particularism".
In the following extract, Geertz has two opposed centrifugal influences:
"Yet out of all this low cunning has come not only the most democratic state in the Arab world [Lebanon], but the most prosperous; and one that has in addition been able to – with one spectacular exception – to maintain its equilibrium under intense centrifugal pressures from two of the most radially opposed extrastate primordial yearnings extant: that of the Christians, especially the Maronites, to be part of Europe, and that of the Moslems especially the Sunnis, to be part of pan-Arabia."
(From 'The integrative revolution: The primordial sentiments and civil politics in the new states')
A cursory reading might be that as these two opposed forces balance there is an equilibrium between them – but the scientist would realise this must be read as there being a strong enough cohesive force to hold the centre together against the combined effect of these forces – think perhaps of the famous Magdeburg hemispheres where two teams of forces were unable to pull apart two hemispheres with a vacuum between them (so that the pressure of air pushing on the outside spheres applied sufficient force to balance the maximum pull the horses could manage).
Engraving showing Otto von Guericke's 'Magdeburg hemispheres' experiment (Source: https://commons.wikimedia.org/wiki/File:Magdeburg.jpg)
Again, the metaphor might well lead a reader to apply, and so reinforce, their notions of forces acting – whether these notions match the canonical science account or not.
Some other scientific references.
Among the other scientific concepts I noticed referenced were
"A cockfight is …not vertebrate enough to be called a group…"
"…the intense stillness that falls with instant suddenness, rather as someone had turned off the current…"
"…that is like saying that as a perfectly aseptic environment is impossible, one might as well conduct surgery in a sewer."
"there has almost universally arisen around the developing struggle for governmental power as such a broad penumbra of primordial strife."
Sharing scientific and cultural resources
The very way that language evolves means that words change, or acquire new, meanings, and also shift between domains. If scientific terms are used enough figuratively, metaphorically, as part of non-scientific contexts then in time they will acquire new accepted non-technical meanings. We see this shift from metaphorical to widely accepted meanings in the establishment of idioms which must sometimes be quite mystifying to those not familiar with them, like non-native language speakers (Taber, 2025): understanding an idiom is not rocket science to the initiated, but the language learner might feel they've missed the boat or are having their leg pulled – and, if already struggling with the language, may consider them the last straw.
Indeed, there is a scholarly equivalent. So, I suspect many natural scientists may not know what a Procrustean bed is, or the significance of finding yourself between Scylla and Charybdis ("I'll have a chocolate and strawberry Scylla in a cone, and a bottle of 1990 Charybdis please"?), but such references are common in academic writing in some fields.
But scientists are in no position to complain when technical terms drift into figurative use in everyday language. After all, scientists are not above borrowing everyday terms metaphorically, and then through repeated use treating them as if technical terms. Certainly (as I describe in detail elsewhere, 'The passing of stars: Birth, death, and afterlife in the universe'), references to the 'births' and 'deaths' of stars are now used as formal technical terms in astronomy; but this is nothing new, for 'charge', as in electrical charge, was borrowed from the charge used in early firearms; and quarks originated in James Joyce – and calling them 'up', 'down', 'truth'/'top', 'beauty'/'bottom' and their qualities as 'strangeness' and 'charm' gave new meanings to terms taken from common usage. And having been sequestered by physics, they have then been borrowed back into popular culture again by the likes of Hawkwind and Florence and the Machine. 9
So, I have no criticisms of Geertz in using scientific terms figuratively in his writings about culture- even if sometimes those uses seem a little forced; and even if inevitably (simply because this is how human memory works) when such terms are used without definition or explication they may actually activate and reinforcealternative conceptions in those who already hold misconceptions of the science. A communicator has to draw upon the resources they have available, and which they hope will resonate (sic) with their audience in order to bring about the challenging task of sharing ideas between minds.
I read Geertz to find out a little more about his area of (social) science, but ended up reflecting especially upon how he used the language of natural science and how this might be understood by non-scientists. It has been suggested there is no privileged meaning to a text, as each reader brings their own personal reading. I do not entirely agree, at least with regard to non-fiction. There is certainly no meaning in the text itself (it is just the representation of the author's ideas and needs to be interpreted) but there is an intended meaning that the author hopes to communicate, and which the author seeks to privilege by using all the rhetorical tools available in the hope that readers will understand the texts much as intended. As every teacher likely knows: that is not an automatic or easy task.
Sources:
Change, H. (2004) Inventing Temperature: Measurement and Scientific Progress. Oxford University Press.
Clifford Geertz (2000) After the revolution: The fate of nationalism in the new states (first published 1971), in The Interpretation of Cultures. Selected Essays (2nd Edition). New York. Basic Books, pp.234-254
Clifford Geertz (2000) Deep play: notes on the Balinese cockfight (first published 1972), in The Interpretation of Cultures. Selected Essays (2nd Edition). New York. Basic Books.
Clifford Geertz (2000) Person, time, and conduct in Bali (first published 1966), in The Interpretation of Cultures. Selected Essays (2nd Edition). New York. Basic Books, pp.360-411.
Clifford Geertz (2000) Politics past, politics present: some notes on the uses of anthropology in understanding the new states (first published 1967), in The Interpretation of Cultures. Selected Essays (2nd Edition). New York. Basic Books.
Clifford Geertz (2000) Religion as a cultural system (first published 1966), in The Interpretation of Cultures. Selected Essays. 2nd Edition. New York. Basic Books, pp.87-125.
Clifford Geertz (2000) The cerebral savage: on the work of Claude Lévi-Strauss (first published 1967), in The Interpretation of Cultures. Selected Essays (2nd Edition). New York. Basic Books, pp.345-359.
Clifford Geertz (2000) The impact of the concept of culture on the concept of man (first published 1966), in The Interpretation of Cultures. Selected Essays. 2nd Edition. New York. Basic Books, pp.33-54.
Clifford Geertz (2000) The integrative revolution: The primordial sentiments and civil politics in the new states (first published 1963), in The Interpretation of Cultures. Selected Essays (2nd Edition). New York. Basic Books, pp.255-310
Clifford Geertz (2000) Thick description: toward an interpretative theory of culture, in The Interpretation of Cultures. Selected Essays. 2nd Edition (1973), pp.3-30.
1 We often say exactly 100˚C, but in practice factors such as the container used do make measurable differences – (Chang, 2004) – that we generally ignore.
2 Life is not always so simple. Sulphur, for example, forms different crystal structures at different temperatures; and many metals also undergo 'phase transitions' between structures at different temperatures. But we think our theories can also explain this, so we can generalise about, say, the shape of all sulphur crystals formed below 96˚C.
3 That is, before Darwin it was widely believed that species represented clear cut types of beings where in principle clear demarcation lines could be established between different natural kinds. We now understand that even if at any one time this is approximately true (see the figure), taking a broader perspective informed by Darwin's work we find different types of organisms blend into each other and there is no absolute boundary around one species distinguishing it from others. See, for example, 'Can ancestors be illegitimate?'
The scientific perspective on the evolution of living things considers 'deep time' whereas the everyday experience of learners is limited to a 'snapshot' of the species alive at one geological moment (from Taber, 2017).
4 This is a tricky area for the science educator. Scientists should always be open to alternative explanations, and even the overthrow of long accepted ideas. But sometimes the evidence is so overwhelming that for all practical purposes we assume we have certain knowledge. There are alternative explanations for the vast evidence for evolution (e.g., an omnipotent creator who wants to mislead us) but these seem so unfeasible and convoluted that we would be foolish to take them too seriously.
When it comes to climate change, we can never be absolutely sure the effects we are seeing are due to the anthropogenic actions we believe to be damaging, but the case is so strong, and the consequences of not changing our behaviours so serious, that no reasonable person should suggest delaying remedial action. This would be like someone playing 'Russian roulette' with a revolver with only one empty chamber. They cannot be sure they would shoot themselves, so why not go ahead and pull the trigger?
Similar arguments relate to the Apollo moon landings. One can imagine a highly convoluted ongoing global conspiracy to fake the landings with all the diverse evidence – but this requires accepting a large number of incredibly infeasible propositions. (Read: 'The moon is a long way off and it is impossible to get there'.)
5 The radical poet (and engraver and visionary) William Blake:
"To see a world in a grain of sand
And a heaven in a wild flower,
Hold infinity in the palm of your hand
And eternity in an hour."
6 Even in the natural sciences, this depends upon how we think about the instrument used. If the instrument and technique are considered basic and simple and relivable, and 'standard' for the job in hand (part of the 'disciplinary matrix' of an established research field), we may not bother adding 'as measured with the metre rule' or 'according to the calibrated markings on the measuring cylinder' and then describe how we used the rule or cylinder. However, if a technique or instrument is new, or considered problematic, or known to be open to large errors in some contexts, we would be expected to give details.
7 Supposedly, according to the premise of 'Space: 1999', by 1999 the people of earth had amassed a vast stockpile of nuclear waste which was stored on one location on the moon. Even more supposedly, this was meant to have exploded with sufficient force to eject the moon from earth orbit and indeed the solar system, but without the moon actually losing its structural integrity. Just as unlikely, the space through which the moon moved was so dense with other planetary systems that the humans stranded on the moon at the time of the accident were able to engage in regular interplanetary adventures. Despite the fact that
"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
Douglas Adams
and that generally interstellar distances are vast, the projectile moon moved fast enough to quickly reach new alien civilizations but slowly enough to allow some interaction before passing by. (It was just entertainment. Extremely long sequences of episodes where the moon just moved through very tenuous gas and the odd dust cloud, and incrementally approaches some far star, may have been much more realistic, but would not have made for exciting television.)
Actors Martin Landau and Barbara Bain (seen in the publicity shot for 'Space: 1999' reproduced above) were a married couple who starred in 'Space: 1999', having previously appeared together in the classic series 'Mission: Impossible' – which also featured one Leonard Nimoy (see below) who also famously later ventured into space as Mr Spock.
The 'Mission: Impossible' team. "No Jim, not impossible captain, just very challenging."
8 From the perspective of general relativity, an orbiting body is simply following a geodesic in the curved space around a massive body, so gravitational force might be seen as an epiphenomenon: fictitious – a bit like centrifugal force.
9
"Copernicus had those Renaissance ladies Crazy about his telescope And Galileo had a name that made his Reputation higher than his hopes Did none of these astronomers discover While they were staring out into the dark That what a lady looks for in her lover Is charm, strangeness and quark"
From the lyrics of 'Quark, strangeness and charm' (Dave Brock, Robert Newton Calvert)
"The static of your arms, it is the catalyst Oh the chemical it burns, there is nothing but this It's the purest element, but it's so volatile An equation heaven sent, a drug for angels Strangeness and Charm"
From the lyrics of 'Strangeness and Charm' (Florence Welch Paul Epworth)
"in the past we have tried to address this by controlling industrial sources that are close to the earth where the chemicals have to work a lot harder to get to the ozone layer"
Language as a source of understanding – or confusion
Language can seem more like sorcery than science.
A person has an idea, something that is an internal, personal, mental experience, and by making some sounds or inscribing some symbols on a page or board, another person can acquire the idea.
But, like all powerful magic, it only works in the right circumstances, when the ritual is followed carefully – or else the spell may be broken. In other words, although it is quite amazing how we can effectively communicate through language (something humans have evolved over an extended period to be able to learn to do), successful communication is by no means assured. Teachers are only to well aware of that. A carefully designed, clearly explained, well-paced, presentation may lead to
And, indeed, sometimes in the classroom the same presentation can lead to all three. Communication is effective to the extent it is designed to fit with the characteristics of the 'receiving device'. And just as an F.M. transmission will not be effectively picked up by a radio tuned to medium wave or long wave frequencies (or, for young readers, who only know about digital radios – perhaps think about those times when you have a device with one type of output cable, which you are trying to connect to another device which only has input sockets for other types of connector), every learner in the class brings a unique set of interpretive resources for making sense of teaching.
A large part of the work of the teacher (or other science communicator) is helping to make the unfamiliar seem familiar by using language to describe it, or comparing it to something learners will hopefully already be familiar with.1 We use various comparisons like analogies (e.g., 'molecules in a solid are like angry dogs on short chains') and figures of speech such as similes ('an immune response is like a fire'), to help learners get an initial image they can understand, even if often this is only a starting point that needs to be further developed. The teacher, then, is operating with a model (if sometimes only a tacit one) of the resources available to learners for interpreting teaching – and clearly there is a limit to how much teachers can know about what their students are already familiar with.
These kind of tropes (similes, metaphors, etc.) are also found in popular science writing, science journalism, and scientists' own accounts of their work. Since retiring from my own teaching role, I have had more time for reading, and have become quite obsessed with just how common such comparisons are -as well as how obscure some examples seem to be.
That is, figurative language is meant to communicate by linking to something already familiar, but sometimes I do wonder just what the average reader of popular science works or science journalism make of some of the examples I come across. If I was still in post (and had the energy to match my inquisitiveness) I would love to set up some research to find out just what learners would make of some of these examples. Some instances, I am sure, are clear enough, but others seem to require much interpretation or draw upon references that may not be familiar. In the case of historical writings, what were at the time useful references may now be archaic (as when Charles Darwin describes the shape of part of a flower as being like those devices used in London [sic] kitchens to catch cockroaches – you know the ones!)
In some cases I suspect I can only understand the comparison because I already know the science. If you want some convincing of that, you might like to take a look at some examples I have noted down and see which you feel are clear and obvious enough to get an idea across to someone new to the science:
A particular type of figurative language is anthropomorphism where we refer to non-human entities (ants, trees, crystals, clouds, etc.) as if they were humans with human attributes – feelings, competencies, thoughts, motivations, desires and so on (e.g., 'the biosphere has learned to recycle phosphorus'). When anthropomorphism occurs in scientific explanations it can be considered as a kind of pseudo-explanation: something which gives the impression of an explanation, but without employing valid scientific concepts and reasoning.2 (The biosphere has not learned to do anything.)
Although anthropomorphic language may only be used figuratively, and so is not meant to be taken literally, learners may not fully appreciate this. How many students, even at A level, think that chemical reactions occur because the atoms involved want or need to acquire full electrons shells or outer-shell octets? That is a rhetorical question – but I know from experience, many. (Of course, it is a nonsense, even in its own terms, as nearly all the reactions learners meet in school science involve both products and reactants which fit the octet rule.) 3
But then, sometimes, such figurative language offers economy, avoiding the need for complex explanations. So, perhaps there is a balance of considerations – but I am always somewhat wary of anthropomorphic explanations in science.
Hard working chemicals?
These thoughts were (once again) provoked by something I heard on a podcast this morning. I was listening to an episode of the BBC Inside Science programme/podcast, and heard:
"…our aircraft only really release chemicals up until about ten to twelve km, whereas these rockets are going all the way to eighty, a hundred kilometres, so putting these chemicals into multiple layers in the atmosphere. One of these layers is a layer of ozone that is crucial for protecting us from harmful UV radiation. And so, you know, in the past we have tried to address this by controlling industrial sources that are close to the earth where the chemicals have to work a lot harder to get to that layer, but now, with rockets, we can just put them directly into that layer."
Prof. Eloise Marais (Professor of Atmospheric Chemistry and Air Quality, UCL)
Now what struck me was the phrase " the chemicals have to work a lot harder to get to that layer". This is anthropomorphic as it implies that these chemicals are deliberately acting in order to reach the so-called 'ozone layer'.4 Of course they are not. These are just natural processes – physical processes that do not involve any chemicals working hard. Indeed, the molecules of these chemicals are passive subjects moved around without their knowledge or consent! (Because, of course, they are not the type of entities capable of knowing anything or giving consent, let alone actively working towards a goal.)
But the phrasing was economic. I challenged myself to rewrite the phrase "in the past we have tried to address this by controlling industrial sources that are close to the earth where the chemicals have to work a lot harder to get to that layer" without the anthropomorphism.
anrthropomorphic
rewritten
"…in the past we have tried to address this by controlling industrial sources that are close to the earth where the chemicals have to work a lot harder to get to that layer…"
"…in the past we have tried to address this by controlling industrial sources that are close to the earth where the chemicals take a lot longer to reach that layer because this relies on the diffusion of gas molecules through the air, and the effect of convection currents mixing up different regions of the atmosphere…"
Now, I am not an atmospheric chemistry expert (unlike Prof. Marais) but that seems a more scientific explanation. And I would imagine that in her mind Prof. Marais understands this process in a similar – if likely more sophisticated, and certainly more detailed – way. But she chose (perhaps deliberately, perhaps not given our use of language in speech is partially automatic – we do not fully script what we are going to say before we start to talk) to anthropomorphise rather than specify a scientific mechanism. I doubt many listeners took the figure of speech here as literal (although you never know!) and Prof. Marais kept her comments more economic by not introducing ideas that were perhaps peripheral to her message: anthropocentric inputs into the atmosphere reach the stratosphere, where some polluting chemicals react with ozone, much more readily if we send them directly there by rocket, rather than release them near the ground.
Anthropomorphism, as a kind of humanising language, has been said to be useful to engage learners, as well as sometimes (as in the example here) being a way to avoid the need to go into technical details that may be quite unrelated to the main point being made. People can respond well to anthropomorphism, being more attentive and receptive to ideas presented in human terms (so, perhaps referring to hard working chemicals engaged listeners more than simply saying: "in the past we have tried to address this by controlling industrial sources that are close to the earth where the chemicals take a lot longer to reach that layer").5
Therefore, I am not saying this was wrong or poorly judged, but whenever I hear such examples it makes we wonder if the causal listener who is not a scientist would notice the anthropomorphism, and realise that it was being used as an engaging alternative to a dry technical phrase, or even as an abbreviated placeholder for a more technical description. And this is not an example of something rare – anthropomorphic explanations are again very common in science writing and discourse. I have compiled some examples that I have noticed:
In some of those cases I suspect non-scientists may well find the language used quite persuasive, and not appreciate that 'explanations' presented in anthropomorphic terms are not scientifically valid. So, although I can certainly see the case for its use, I tend to be uneasy when I hear or read anthropomorphic statements that stand in the place of scientific accounts, as I know they can be persuasive and are sometimes adopted as explanations by learners.
I wonder what other science teachers think?
Notes:
1 In order for learners to make sense of abstract, complex ideas these need to:
preferably be experienced or demonstrated; or when that is not possible,
modelled/simulated; or when that is not possible,
explained in terms of ideas the learners can already relate to.
2 There are different types of pseudo-explanations, such as tautology, presenting a description as if it is an explanation, offering a label as though that explains, etc.
3 I think this is perhaps the most widespread type of misconception in school chemistry – that reactions occurs so that atoms can get full shells (or octets), that entities with full shells are always the more stable, that atoms of ions with fulls shells cannot be ionised, that atoms will spontaneously lose electrons to get a full shell, etc., and, indirectly from this, that the bonding power of ions is determined by electrovalency (so, in NaCl, the Na+ ion and the Cl– ion are each thought to be restricted to forming one ionic bond).
4 Experts, such as science teachers, know that the 'ozone layer' is not a layer of ozone, but it should not surprise us when learners think that is what the term means!
5 Perhaps, metaphorically, "…the chemicals have to work a lot harder to get to that layer…" is a 'warmer' expression than the 'colder' phrase "the chemicals take a lot longer to reach that layer"?
(Possibly) the first in an occasional series to test the imagination of science teachers and other science communicators.
Those who explain science (such as teachers, scientists themselves, journalists) often seek to 'make the unfamiliar familiar' by suggesting that the novel scientific concept is in some ways like something else – something it is assumed will already be familiar with the audience.
Can you match the science and the comparison?
In the table below I have selected ten examples of comparisons for science concepts (from those reported on this website) – but I have separated the scientific ideas from the comparisons (and then presented both lists alphabetically).
The challenge is to see if you can identify which comparison was used in discussing which scienceconcept:
Can you work out which comparisons were used in explaining the different science concepts?
Of course, it is very unfair of me to present these comparisons stripped of any context – but that is what makes it a challenge.
[All of these examples are featured somewhere on the site, so if you give up (or wish to 'cheat') you could use the 'Search the website' box. If you admit defeat, the answers are at at the bottom of the post.]
A fun activity – with a serious point
I hope some readers may find this a fun activity for a tea break in the prep. room or as a way to relax for those now finally on Summer break. However, I think such comparison invite closer attention.
Devices such as analogies and similes are invaluable in getting across abstract unfamiliar ideas. However, choosing them is itself a challenge as the comparison has to be familiar to the learner/listener/reader or it cannot be helpful (in which case it may be demotivating as it adds an additional burden to what the person does not know!) Moreover, the learner/listener/reader needs to appreciate which aspect of the comparison is being highlighted as relevant. (In an analogy this should be mapped out – but in metaphors and similes it is left implicit).
There is also a danger that these devices – so useful for introducing scientific ideas – outstay their welcome (so to speak). An author of a popular science book may only be concerned with the reader having the (subjective) impression of understanding, feeling 'oh yes, that makes sense'; but the science teacher aims for objective understanding (that would be creditable on examination), and intends the analogy or simile to be a temporary 'scaffold' toward understanding which will not be needed once the scientific concept has been learnt and consolidated. Yet, sometimes, learners do not move beyond the comparison – seeing its meaning as literally accurate (much as learners may not appreciate that many scientific models are not intended to be realistic and complete accounts).
Science communicators – scientists, teachers, science writers and the like – are also often knowledgeable about a wide range of topics and cultural references – but these may not always be shared by some of their target learners/listeners/readers. (This may be particularly true when a source is being used in another part of the world to where it was created, or perhaps when a scientist's work is read many decades after being composed.)
These are also highly intelligent people who may have strong powers of imagination – so sometimes they may form creative connections which others may find obscure and idiosyncratic!
Does discriminatory language suggest biologists are ashamed of some of their ancestors?
Keith S. Taber
Historically, some offspring have been classed as illegitmate and so unable to claim the same rights as those recognised as legitimate children.
But are biologists treating some of our ancestors as illegitimate?
This is a bit like judges in a court of appeal announcing their decision as "the appeal is successful – the criminal is innocent".
I was listening to an old podcast recently. The first item was about how nearly all Inuits have a particular genetic variation that is adaptive to living in the Arctic with the extreme cold and restricted diet that involves. These particular genes are not unique to that group, but are only found with much lower incidence in other groups living elsewhere. These genes are in the human 'gene pool', but have been strongly selected for among Inuit communities where they are now ubiquitous.
However, what was seen as especailly interesting about this particular genetic resource was its 'origins' – from another species. These genes are considered to have arisen in Homo sapiens by transfer from another species: Denisovans.
I do not think that any present day humans have any Denisovan or Neanderthal genes
So, the claim is that modern humans have some Denisovan genes just as (according to scientific studies) we have some Neanderthal genes, and probably genes from some other archaic human species as well. Actually I argue below this is not the case, but my argument is in terms of semantics rather than being a rejection of the substantive claims.
So – spoiler alert – I do not think that any present day humans have any Denisovan or Neanderthal genes, but I am happy to accept that we may have genes acquired from other human species such as the Denisovans and Neanderthals. To explain the distinction it is useful to ask how did 'we' modern humans come to be given this genetic gift?
Who counts as an ancestor?
What I thought was of special note in this item of the episode of BBC Inside Science was the language in which it was explained. The programme description suggested:
"Can Inuit people survive the Arctic cold thanks to deep past liaisons with another species? Adam Rutherford talks to geneticist Rasmus Nielsen who says that's part of the answer. His team's research has identified a particular section of the Inuit people's genome which looks as though it originally came from a long extinct population of humans who lived in Siberia 50,000 years ago. The genes concerned are involved in physiological processes advantageous to adapting to the cold. The conclusion is that at some point, the ancestors of Inuits interbred with members of this other species of human (known as the Denisovans) before people arrived in Greenland."
https://www.bbc.co.uk/programmes/b08558n5
The expert interviewed on the episode explained:
"…what we think we can conclude now is that in fact this D.N.A. that we find in the inuits, that we think was important for them in adapting to this extreme environment, that actually was transferred to them from Denisovans or from somebody related to the Denisovans, and by transferred, how does that work, well that works by interbreeding, so in the past we know there has been some interbreeding between these Denisovans and the ancestors of modern humans, and when they interbreed of course you transfer D.N.A."
Prof. Rasmus Nielsen, University of California at Berkely
At the end of the item, the presenter reiterated:
"So, the ancestors of Inuits bred with the Denisovans, and the gift of that blessed union, were genes that helped with cold adaptation."
Dr Adam Rutherford
Now I am not a biologist, and so am perhaps I missing a nuance of how terms tend to be used in biological discourse, but all three of these statements seem to include the same logical fault.
The 'interbreeding' events being referred to are a great many generations back in time, but to ilustrate my complaint, I have prepared a much simplified diagram modelling the scenario presented in the programme, but with just a few generations:
A simplified representation of who counts as an ancestor – according to some biological discourses
Excluding ancestors from minority groups
Now it seems the account being presented by biology here only makes sense if we distort the usual meaning of 'ancestor'. Surely a person's ancestors are all those people who feature on direct lines of descent to that person? In my simplified figure the individual at the bottom has eight great-grandparents.1 In my understanding of 'ancestor', each of these eight people is an ancestor of the individual shown in the final generation. If that is accepted then each of the quotes above is misphrased:
at some point, the ancestors of Inuits interbred with members of this other species of human (known as the Denisovans)
in the past we know there has been some interbreeding between these Denisovans and the ancestors of modern humans
the ancestors of Inuits bred with the Denisovans
Well, no. Surely what is meant here is:
at some point, those ancestors of Inuits considered members of Homo sapiens interbred with other ancestors of Inuits who were members of this other species of human (known as the Denisovans)
in the past we know there has been some interbreeding between these Denisovans and the other ancestors of modern humans
the ancestors of Inuits considered members of Homo sapiens bred with the ancestors of Inuits considered Denisovans
The original statements are akin to telling someone that they are the result of their parent coupling with a communist (or: an Australian / a graphic designer / a Liverpool supporter / a goth / a sociologist, etc.), as if a communist (or sociologist, or whatever) does not deserve to be recognised as a genuine parent.
There seems to be discriminatory language here, a kind of speciesism, where only those ancesters we consider part of 'our' species count as proper ancestors, and so other kinds of human are illegitimate as ancestors.
Two types of sex: Normal sex…and something a little shameful?
This is reflected in implying that there is some abnormal type of sex going on between these different classes of humans. Normal sex is all about genetic recombination (that is, the advantage of sexual over asexual reproduction is the 'shuffling' of genes from two individuals to give different, and pretty much unique, genetic permutations in the offspring).2
But the 'interbreeding' between species is described in particular language – a 'transfer' of genes. Now, in some parts of the living world we do see a kind of transfer of genes where one organism 'donates' copies of some its genes to another organism.
That is somewhat different from breeding in human populations that relies on meiosis to produce gametes that each have half of the parental nuclear genes; and which co-contribute to a new version of the human genone when fertilisation occurs due to the fusion of two gametes – nothing is actually transferred. Like downloading a file from a website where there is not really a 'file transfer' but the copying of an orginal that remains where it was. 3
That process of sexual reproduction is what occured when two ancestors bred – regardless of whether both were Homo spaiens or one is Denisovan (or Neanderthal or some other type). So, what is meant by 'transfer' is presumably that some 'Denisovan genes' were copied into the H. sapiens gene pool.
The species question
This description would make sense if species were ontologically discrete entities. But, as Darwin (1959) long ago realised, there are not sharp, absolute distinctions between species, and biological demacractions of species are more matters of 'convenience'. If we have some 'Denisovan D.N.A.' or 'Neanderthal D.N.A.' in our genomes, then – assuming the Denisovans or Neanderthals did not have genetic engineering skills long before 'us' – then the Denisovans or Neanderthals are our ancestors.
And why not? The very logic of evolution is that if we go back far enough in time we have:
non H. Sapiens, indeed, eventually,
non-human,
non-primate, even
non-mammalian, ancestors.
Humans today may be different from Denisovans or Neanderthals, but then we are also surely somewhat different to early sapiens who had not yet got friendly enough with Denisovans or Neanderthals to have received 'transferred' genes.
So, is the language here, of transferring genetic matieral by interbreeding (contrasted with the genetic recombination occuring when speciments of H. sapiens bred), reflecting a traditonal view of species that Darwin invalidated?
That is, under the old definition, members of two different species cannot breed to provide offspring, or at least, not fertile offspring. But the Denisovans and Neanderthals that 'interbred' with our (other) ancestors and passed copies of their genes indirectly down to humans today, clearly had no trouble in that department. Nor can it be argued that these were geographically separated populations that never overlapped, and so can be considered consequently as if separate species. Clearly there must have been some degree of co-habitation between these groups to allow matings to occur.
There may be significant enough objective differences between the morphology of early Sapiens, Denisovans and Neanderthals for biologists to feel these should be considered different species, but the notion that Denisovans and Neanderthals can simply be considered as being distinct entities on other discrete branches of the evolutionary bush is challenged by the evidence that at least some of themare among our direct ancestors. Perhaps only a minority of the Denisovans and Neanderthals that shared the world with Homo sapiens have offspring alive today – but then that would likely also be true for their sapien peers.
The science teacher and philsopher Gaston Bachelard has described how science is often impeded by retaining the 'fossilised' infuence of historical ideas that science has supposedly moved on from. Is this an example? The BBC Inside Science podcast seems to be telling us we need to rethink what we mean by our ancestors, whilst using that very word without taking this into account. This is a bit like the judges in a court of appeal announcing their decision as "the appeal is successful – the criminal is innocent".
No more discriminatory language
Or, is this an example of using language loosely to communicate effectively, because being precise would lead to convoluted expressions [like my 'at some point, the ancestors of Inuits considered members of Homo sapiens interbred with other ancestors of Inuits who were members of this other species of human (known as the Denisovans)']?
Modern humans do not actually have Denisovan or Neanderthal genes, or Denisovan or Neanderthal D.N.A., but rather have some genes that are identical (or very similar) to – in effect indirect copies of – some genes of their Denisovan or Neanderthal ancestors. And no doubt those genes (or rather identical genes 4) could also be found in some of their even more distant ancestors who are in turn considered a different species again. After all, humans share many genes with many other living things, such as bananas, so references to 'human genes' or 'Denisovan genes' it is a bit like referring to characters in the Roman alphabet as 'English letters', when they are equally 'French letters' or 'Dutch letters', etcetera. They are letters that appear in English language texts, but they are not exclusive to English language texts: just as there are genes found in human genones that are not exclusive to human genones.
Referring to 'Denisovan genes' or 'Denisovan D.N.A.' speeds communication. But it has potential to mislead the non-specialist.
So, I object to any of my forebearers who happen not to be considered specimens of Homo sapiens being said to 'transfer' genes when they 'interbred' with my ancestors: they are just as much my ancestors as those partners they engaged in genetic recombination with.
So, please, no more more discriminatory language directed against some of our ancestors, just because they were in minority human groups.
Work cited:
Bachelard, G. (1938/2002). The formation of the scientific mind. A contribution to a psychoanalysis of objective knowledge (M. McAllester Jones, Trans.). Clinamen Press.
1 In a genuine family 'tree' there are likely to be mulitple offspring from some unions, and indeed often some people will parent children with multiple partners – but this would over-complicate the diagram as it is not central to the argument being made.
In a case such as this with just four generations we would expect a person to normally have eight different great grandparents who are all unambigously three generations distant from that individual. As we consider much longer time periods it becomes increasing likely that the same ancestor occupies several (indeed, many) 'slots' on the tree (you have many fewer than 2ndistinct ancestors going back n generations once n gets large) and indeed these individuals may appear in the tree across several generations.
Another way of thinking about this is that not all of your (great)n grandparents will have been alive at the same time, once n starts is more than a small number. As an extreme case, it is quite possible that the offspring of a union between a 50 year old man and a 20 year old woman (unusual but not unknown) might quite feasibly have had one pair of grandparents who died before the other grandparents were born. This is unlikely, but plausible. With each additional generation it becomes less likely that all your ancesters at that remove were alive at the same time.
2 The advantage of asexual reproduction is that the outcome should be a viable specimen in the envrionment occupied by the parent that has been cloned. Perhaps the most advanced reproducers are those species that are able to reproduce by either strategy?
3 And, just as teaching does not seek to 'transfer knowledge' from the teacher.
4 Perhaps one issue here is how we can use the term, gene, to refer both to functional sequences of nucleic acid in abstract (as we might refer to 'the carbon atom' when we mean all and any carbon atoms, not a specific one), and actual material samples. In the first sense, a parent and offspring can share the same gene; in the second sense, a copy of a parent's gene can be passed to the child. In neither sense does the 'transfer' of genes occur.
I was recently listening to a podcast of an episode of a science magazine programme which included two items of astronomy news, one about a supernovae, the next about a quasar. I often find little snippets in such programmes that I think work making a note of (quite a few of the analogies, metaphors and similes – and anthropomorphisms – reported on this site come from such sources). Here, I went back and listened to the items again, and decided the discussions were rich enough in interesting points to be worth taking time to transcribe them in full. The science itself was fascinating, but I also thought the discourse was interesting from the perspective of communicating abstract science. 1
I have appended my transcriptions below for anyone who is interested – or you can go and listen to the podcast (episode 'Largest ever COVID safety study' of the BBC World Service's Science in Action).
Space, as Douglas Adams famously noted, is big. And it is not easy for humans to fully appreciate the scales involved – even of say, the distance to the moon, or the mass of Jupiter, let alone beyond 'our' solar system, and even 'our' galaxy. Perhaps that is why public communication of space science is often so rich with metaphor and other comparisons?
When is a star no longer a star (or, does it become a different star?)
One of the issues raised by both items is what we mean by a star. When we see the night sky there are myriad visible sources of light, and these were traditionally all called stars. Telescopes revealed a good many more, and radio telescopes other sources that could not detected visually. We usually think of the planets as being something other than stars, but even that is somewhat arbitrary – the planets have also been seen as a subset of the stars – the planetary or wandering stars, as opposed to the 'fixed' stars.
At one time it was commonly thought the fixed stars were actually fixed into some kind of crystalline sphere. We now know they are not fixed at all, as the whole universe is populated with objects influenced by gravity and in motion. But on the scale of a human lifetime, the fixed stars tend to appear pretty stationary in relation to one another, because of the vast distances involved – even if they are actually moving rather fast in human terms.
Wikipedia (a generally, but not always, reliable source) suggests "a star is a luminous spheroid of plasma held together by self-gravity" – so by that definition the planets no longer count as stars. What about Supernova 1987A (SN 1987A) or quasar J0529-4351?
"This image, taken with Hubble's Wide Field and Planetary Camera 2in 1995, shows the orange-red rings surrounding Supernova 1987A in the Large Magellanic Cloud. The glowing debris of the supernova explosion, which occurred in February 1987, is at the centre of the inner ring. The small white square indicates the location of the STIS aperture used for the new far-ultraviolet observation. [George Sonneborn (Goddard Space Flight Center), Jason Pun (NOAO), the STIS Instrument Definition Team, and NASA/ESA]" [Perhaps the supernova explosion did not actually occur in February 1987]
Supernova 1987A is so-called because it was the first supernova detected in 1987 (and I am old enough to remember the news of this at the time). Stars remain in a more-or-less stable state (that is, their size, temperature, mass are changing, but, in proportional terms, only very, very slowly2) for many millions of years because of a balance of forces – the extremely high pressures at the centre work against the tendency of gravity to bring all the matter closer together. (Imagine a football supported by a constant jet of water fired vertically upwards.) The high pressures inside a star relate to a very high temperature, and that temperature is maintained despite the hot star radiating (infra-red, visible, ultraviolet…) into space 3 because of the heating effect of the nuclear reactions. There can be a sequence of nuclear fusion reactions that occur under different conditions, but the starting point and longest-lasting phase involves hydrogen being fused into helium.
The key point is that when the reactants ('fuel') for one process have all (or nearly all) been reacted, then a subsequent reaction (fusing the product of a previous phase) becomes more dominant. Each specific reaction releases a particular amount of energy at a particular rate (just as with different exothermic chemical reactions), so the star's equilibrium has to shift as the rate of energy production changes the conditions near the centre. Just as you cannot run a petrol engine on diesel without making some adjustments, the characteristics of the star change with shifts along the sequence of nuclear reactions at its core.
These changes can be quite dramatic. It is thought that in the future the Earth's Sun will expand to be as large as the Earth's orbit – but that is in the distant future: not for billions of years yet.
Going nova
Massive stars can reach a point when the rate of energy conversion drops so suddenly (on a stellar scale) that there is a kind of collapse, followed by a kind of explosive recoil, that ejects much material out into space, whilst leaving a core of condensed nuclear matter – a neutron star. For even more massive stars, not even nuclear material is stable, as there is sufficient gravity to even collapse nuclear matter, and a black hole forms.
It was such an explosion that was bright enough to be seen as a 'nova' (new star) from Earth. Astronomers have since been waiting to find evidence of what was left behind at the location of the explosion – a neutron star, or a black hole. But of course, although we use the term 'nova', it was not actually a new star, just a star that was so far away, indeed in another galaxy, that it was not noticeable – until it exploded.
Dr. Olivia Jones (from the UK Astronomy Technology Centre at The Royal Observatory, Edinburgh) explained that neutron stars form from
"…really massive stars like Supernova 1987A or what it was beforehand, about 20 times the mass of a Sun…
So, what was SN 1987A before it went supernova? It was already a star – moreover, astronomers observing the Supernova were studying
…how it evolves in real time, which in astronomy terms is extremely rare, just tracing the evolution of the death of a star…
So, it was a star; and it died, or is dying. (This is a kind of metaphor, but one that has become adopted into common usage – this way of astronomers talking of stars as having births, lives, careers, deaths, has been discussed here before: 'The passing of stars: Birth, death, and afterlife in the universe.') What once was the star, is now (i) a core located where the star was – and (ii) a vast amount of ejected material now "about 20 light years across" – so spread over a much larger volume than our entire solar system. The core is now a "neutron star [which] will start to cool down, gradually and gradually and fade away".
So, SN 1987A was less a star, than an event: the collapse of a star and its immediate aftermath. The neutron star at is core is only part of what is left from that event (perhaps like a skeleton left by a deceased animal?) Moreover, if we accept Wikipedia's definition then the neutron star is not actually a star at all, as instead of being plasma (ionised gas – 'a phase of matter produced when material is too hot to exist as, what to us seems, 'normal' gas) it comprises of material that is so condensed that it does not even contain normal atoms, just in effect a vast number of atomic nuclei fused into one single object – a star-scale atomic nucleus. So, one could say that SN 1987A was no so much a star, as the trace evidence of a star that no longer existed.
And SN 1987A is not alone in presenting identity problems to astronomers. J0529-4351 is now recognised as being possibly the brightest object in the sky (that is, if we viewed them all from the same distance to give a fair comparison) but until recently it was considered a fairly unimpressive star. As doctoral researcher Samuel Lai (Research School of Astronomy and Astrophysics, Australian National University) pointed out,
this one was mis-characterised as a star, I mean it just looks like one fairly insignificant point, just like all the other ones, right, and so we never picked it up as quasar before
But now it is recognised to only appear insignificant because it is so far away – and it is not just another star. It has been 'promoted' to quasar status. That does not mean the star has changed – only our understanding of it.
But is it a star at all? The term quasar means 'quasi–stellar object', that is something that appears much like a star. But, if J0529-435 is a quasar, then it consists of a black hole, into which material is being attracted by gravity in a process that is so energetic that the material being accreted is heated and radiates an enormous amount of energy before it slips from view over the black hole's event horizon. That material is not a luminous spheroid of plasma held together by self-gravity either.
This video from the European Southern Observatory (ESO) gives an impression of just how far away (and so how difficult to detect) the brightest object in the galaxy actually is.
These 'ontological' questions (how we classify objects of different kinds) interest me, but for those who think this kind of issue is a bit esoteric, there was a great deal more to think about in these item.
"A long time ago, in a galaxy far, far away"
For one thing, it was not, as presenter Roland Pease suggested, strictly the 37th anniversary of the SN 1987A – at least not in the sense that the precursor star went supernovae 37 years ago. SN 1987A is about 170 000 light years away. The event, the explosion, actually occurred something like 170 000 years before it could be detected here. So, saying it is the 37th anniversary (rather than, perhaps, the 170 037th anniversary4) is a very anthropocentric, or, at least, geocentric take on things.
Then again, listeners are told that the supernova was in "the Large Magellanic Cloud just outside the Milky Way galaxy" – this is a reasonable description for someone taking an overview of the galaxies, but there is probably something like 90,000 light-years between what can be considered the edges of our Milky Way galaxy and this 'close by' one. So, this is a bit like suggesting Birmingham is 'just outside' London – an evaluation which might make more sense to someone travelling from Wallaroo rather than someone from Wolverhampton.
It is all a matter of scale. Given that the light from J0529-4351 takes about twelve billion years to reach us, ninety thousand light years is indeed, by comparison, just outside our own galaxy.
But the numbers here are simply staggering. Imagine something the size of a neutron star (whether we think it really is a star or not) that listeners were informed is "rotating…around 700 times a second". I do not think we can actually imagine that (rather than conceptualise it) even for an object the size of a pin – because our senses have not evolved to engage with something spinning that fast. Similarly, material moving around a black hole at tens of thousands of kilometres per second is also beyond what is ready visualisation. Again, we may understand, conceptually, that "the neutron star is over a million degrees Celsius" but this is just another very big number way that is outside any direct human experience.
Comparisons of scale
Thus the use of analogies and other comparisons to get across something of the immense magnitudes involved:
"If you think of our Sun as a tennis ball in size, the star that formed [SN] 87A was about as big as the London Eye."
"A teaspoon of this material, of a neutron star, weighs about as much as Everest"
the black home at the centre of the quasar acquires an entire Sun worth of mass every single day
the black hole at the centre of the quasar acquires the equivalent of about four earths, every single second
the quasar is about five hundred trillion times brighter than the Sun, or equivalent to about five hundred trillion suns
Often in explaining science, everyday objects (fridges, buses – see 'Quotidian comparisons') are used for comparisons of size or mass – but here we have to shift up to a mountain. The references to 'every single day' and 'every single second' include redundancy: that is, no meaning is lost by just saying 'every day' and 'every second' but the inclusion of 'single' acts a kind of rhetorical decoration giving greater emphasis.
Figurative language
Formal scientific reports are expected to be technical, and the figurative language common in most everyday discourse is, generally, avoided – but communication of science in teaching and to the public in journalism often uses devices such as metaphor and simile to make description and explanations seem more familiar, and encourage engagement.
Of course, it is sometimes a matter of opinion whether a term is being used figuratively (as we each have our own personal nuances for the meanings of words). Would we really expect to see a 'signature' of a pulsar? Not if we mean the term literally, a sign made by had to confirm identify, but like 'fingerprint' the term is something of a dead metaphor in that we now readily expect to find so-called 'signatures' and 'fingerprints' in spectra and D.N.A. samples and many other contexts that have no direct hand involvement.
Perhaps, more tellingly, language may seem so fitting that it is not perceived as figurative. To describe a supernova as an 'evolving fireball' seems very apt, although I would pedantically argue that this is strictly a metaphor as there is no fire in the usual chemical sense. Here are some other examples I noticed:
"we have been searching for that Holy Grail: has a neutron star formed or has a black hole been left behind"
"the quasar is not located in some kind of galactic desert"
there is a "storm, round the black hole"
"the galaxies are funnelling their material into their supermassive black hole"
"extraordinarily hot nuclear ember"
"a dense dead spinning cinder"
"the ultimate toaster"
Clearly no astronomer expects to find the Holy Grail in a distant galaxy in another part of the Universe (and, indeed, I recently read it is in a Museum in Ireland), but clearly this is a common idiom to mean something being widely and enthusiastically sought.5
A quasar does exist in a galactic desert, at least if we take 'desert' literately as it is clearly much too hot for any rain to fall there, but the figurative meaning is clear enough. The gravitational field of the black hole causes material to fall into it – so although the location, at the centre of a galaxy (not a coincidence, of course), means there is much material around, I was not sure how the galaxy was actively 'funnelling' material. This seems a bit light suggesting spilt tea is being actively thrown to the floor by the cup.
A hot ember or cinder may be left by a fire that has burned out, and one at over a million degrees Celsius might indeed 'toast' anything that was in its vicinity. So, J0529-4351 may indeed be the ultimate toaster, but not in the sense that it is a desirable addition to elite wedding lists.
Anthropomorphism
Anthropomorphism is a particular kind of metaphor that describes non-human entities as if they had the motivations, experiences, drives, etc., of people. The references to dying stars at least suggest animism (that the stars are in some sense alive – something that was once commonly believed 6), but there are other examples (that something is 'lurking' in the supernova remnant) that seem to discuss stellar entities as if they are deliberate agents like us. In particular, a black hole acquiring matter (purely due to its intense gravitational field) was described as feeding:
quasars are basically supermassive black holes just swallowing up all the stars and rubbish around
a quasar is feeding from the accretion disc
a monstrous black hole gobbling up anything within reach
just sat [sic] there, gobbling up everything around it
it has to have been feeding for a very, very long time
it will eat about four of those earths, every single second
in a particularly nutritious galaxy
a quasar that has been declared the hungriest object in the universe
The notion of a black hole feeding on surrounding material seems apt (perhaps, again, because the metaphor is widely used, and so familiar). But there seems a lot more 'negative analogy' than 'positive analogy: that is the ways in which (i) a black hole acquires matter, and (ii) an organism feeds, surely have more points of difference than similarity?
For advanced animals like mammals, birds, fish, snails and the like, feeding is a complex behaviour that usually involves active searching for suitable food, whereas the black hole does not need to go anywhere.
The animal has specialist mouth-parts and a digestive system that allows it to break apart foodstuff. The black-hole just tears all materials apart indiscriminately:"it's just getting chopped up, heated up, shredded".
The organism processes the foodstuff to release specific materials (catabolism) and then processes these is very specific ways to support is highly complex structure and functioning, including the building up of more complex materials (anabolism). The black hole is just a sink for stuff.
The organism takes in foodstuffs to maintain equilibrium, and sometimes to grow in very specific, highly organised ways. The black hole just gets more massive.
A black hole surely has more in keeping with an avalanche or the collapse a tall building than feeding?
One person's garbage…?
Another feature of the discourse that I found intriguing was the relative values implicitly assigned to different material found in distant space. There is a sense with SN 1987A that, after the explosion, the neutron star in some sense deserves to be considered the real remnant of the star, whilst the other material has somehow lost status by being ejected and dispersed. Perhaps that makes sense given that the neutron star remains a coherent body, and is presumably (if the explosion was symmetrical) located much where the former star was.
But I wonder if calling the ejected material – which is what comprises the basis of "an absolutely stunning supernova [which is] beautiful" – as 'debris' and 'outer debris"? Why is this material seen as the rubbish – could we not instead see the neutron star as the debris being the inert residue left behind when the rest of the star explored in a magnificent display? (I am not suggesting either should be considered 'debris', just playing Devil's advocate.)
Perhaps the reference to being able to "isolate the core where the explosion was from the rest of the debris" suggests all that is left is debris of a star, which seems fairer; but the whole history of the universe, as we understand it, involves sequences of matter changing forms quite drastically, and why should we value one or some of these successive phases as being the real product of cosmic evolution (stars?) and other phases as just rubbish? This is certainly suggested by the reference to "supermassive black holes in the middle of a galaxy … swallowing up all the stars and rubbish".
Let's hear it for the little guys
Roland Pease's analogy to "the muck at the bottom of your sinkgoing down into the blender" might also suggest a tendency to view some astronomical structures and phenomenon as intrinsically higher status (the blender/black hole) than others (clouds of dust, or gas or plasma – the muck). Of course, I am sympathetic to the quest to better understand "these guys"(intense quasars already formed early in the universe), but as objectively minded scientists we should be looking out for the little guys (and gals) as well.
Appendix A: "the star hidden in the heart of [the] only supernova visible from Earth"
"If you are listening to this live on Thursday, then you're listening to the 37th anniversary of the supernova 1987A, the best view astronomers have had of an exploding star in centuries, certainly during the modern telescope era. So much astrophysics to be learned.
All the indications were, back then, that amidst all the flash and glory, the dying star should have given birth to a neutron star, a dense dead spinning cinder, that would be emitting radio pulses. So, we waited, and waited…and waited, and still there's no pulsing radio signal.
But images collected by the James Webb telescope in its first weeks of operation, peering deep into the ejecta thrown out by the explosion suggest there is something powerful lurking beneath. Olivia Jones is a James Webb Space Telescope Fellow at Edinburgh University and she helped in the analysis."
"87A is an absolutely stunning supernova , it's beautiful, and the fact that you could see it when it first exploded with the naked eye is unprecedented for such an object in another galaxy like this.
We have been able to see how it evolves in real time, which in astronomy terms is extremely rare, just tracing the evolution of the death of a star. It's very exciting."
"I mean the main point is the bit which we see when the star initially explodes , we see all the hot stuff which is being thrown out into space, and then you've got this sort of evolving fireball which has been easiest to see so far."
"Yes, what see initially is the actual explosion of the star itself right in the centre. What happens now is then we had a period of ten years when you couldn't actually see very much in the centre. You needed these new telescopes like Webb and JWST to see the mechanics of the explosion and then, key to this is what was left behind, and we have been searching for that Holy Grail: has a neutron star formed or has a black hole been left behind at the centre of this explosion. And we've not seen anything for a very long time."
"And this neutron star, so this is the bit where the middle of the original star which at the ends of its life is mostly made of iron, just gets sort of crushed under it's own weight and under the force of the explosion to turn itself entirely into this sort of ball of neutron matter."
"Yeah, it's the very, very core of the star. So the star like the Sun, right in the centre is a very dense core, but really massive stars like Supernova 1987A or what it was beforehand, about 20 times the mass of a Sun.
If you think of our Sun as a tennis ball in size, the star that formed 87A was about as big as the London Eye. So it's a very massive star. The pressure and density right in the centre of that star is phenomenal. So, it creates this really, really, compact core. A teaspoon of this material, of a neutron star, weighs about as much as Everest. So, it's a very, a very dense, very heavy, core that is left behind."
"These were the things which were first detected in the 1960s, because they have magnetic fields and they rotate, they spin very fast and they cause radio pulsations and they're called pulsars. so When the supernova first went off I know lots of radio astronomers were hoping to see those radio pulsations from the middle of this supernova remnant."
"Yes. So, we know really massive stars will form a black hole in the centre, 30, 40, 50 solar masses will form a black hole when it dies. Something around 20 solar masses you'd expect to form a neutron star, and so you'd expect to see these signatures, like you said, in the radiowaves or in optical light of this really fastly rotating – by fastly rotating it can be around 700 times a second – but you would expect to see that signature or some detection of that. But even with all these telescopes – with the radio telescopes, X-ray observatories, Hubble – we've not seen that signature, before and so we are wondering, has a black hole been formed? We've seen neutrinos, so we thought the neutron star had formed, but we've not had that evidence before now."
"So, as I understand it, what your research is doing is showing that there's some unexplained source of heat in the middle of the debris that's been thrown out, and that's what your associating which what ought to be a neutron star in the middle, is that roughly speaking the idea?"
"So, the wonderful thing thing about the Webb telescope, you can see at high resolution both the ring, the outer debris of the star, and right at the very centre where the explosion was, but it's not just images we take, so it's not just taking a photograph, we also have this fantastic instrument or two instruments, called spectrographs, which can break down light into their individual elements, so very small wavelengths of light, it's like if you want to see the blue wavelength or the red wavelength, but in very narrow bands."
"And people may have done this at school when they threw some salt into a Bunsen burner and saw the colours, it's that kind of analysis?"
"Yes. And so what we see where the star was and where it exploded was argon and sulphur, and we know that these needed an awful lot of energy, to create these, and I mean a lot, of energy. And the only thing that can be doings this, we compared to many different kinds of scenarios, is a neutron star."
"So this is basically an extraordinarily hot nuclear ember, that's sort of sitting in the middle."
"Yes, right in the middle and you can see this, cause Supernova 1987A is about 20 light years across, in total, and we can isolate the core where the explosion was from the rest of the debris in this nearby galaxy, which I think is fantastic."
"Do you know how hot the surface of this star is and is it just sort of the intense heat, X-ray heat I imagine, that's coming off, that's causing all this radiation that you're seeing."
"I hope you are ready for a very big number."
"Go on."
"The neutron star is over a million degrees Celsius."
"And so, that's just radiating heat, is it, from, I mean this is like the ultimate toaster?"
"Yes, so what eventually will happen over the lifetime of the universe is this neutron star will start to cool down, gradually and gradually and fade away. But that'll be many, many billions of years from now.
What we currently have now is one of the hottest things you can imagine, in a very small location, heating up all its surroundings. I would not want to be anywhere nearby there."
Roland Pease interviewingDr. Olivia Jones (Edinburgh University)
Appendix B: "possibly the brightest object in our universe"
"Now 1987A was, briefly, very bright. Southern hemisphere astronomy enthusiasts could easily spot it in the Large Magellanic Cloud just outside [sic] the Milky Way galaxy. But it was nothing like as bright as JO529-4351 [J0529-4351], try memorising that, its a quasar twelve or so billion light years away that has been declared the brightest object in the universe and the hungriest. At first sight, it's an anonymous, unremarkable spot of light of trillions on [sic] an astronomical photo. But, if you are an astronomer who knows how to interpret the light, as Samual Lai does, you will find this is a monstrous black hole gobbling up anything within reach. Close to the edge of all that we can see."
"So this quasar is a record breaking ultra-luminous object, in fact it is the most luminous object that we know of in the universe. Its light has travelled twelve billion years to reach us, so it's incredibly far object, but it's so intrinsically luminous that it appears bright in the sky."
"And as I understand it, you identified this as being a very distant and bright object pretty recently though you have gone back through the catalogues and its was this insignificant speck for quite a long time."
"Yes, indeed. In fact we were working on a survey of bright quasars, so we looked at about 80% of the sky using large data sets from space satellites. Throughout our large data sets, this one was mis-characterised as a star, I mean it just looks like one fairly insignificant point, just like all the other ones, right, and so we never picked it up as quasar before. Nowadays we are in the era of extremely astronomical, pardon the pun, data sets where in order to really filter thorough them we have these classification algorithms that we use. So, we have the computer, look at the data set, and try to learn what we are looking at, and pick out between stars and quasars."
"Now, is it also interesting, they were discovered about sixty years ago, the first quasars. These are basically supermassive black holes in the middle of a galaxy that's just swallowing up all the stars and rubbish just around it, and that's the bit that for you is quite interesting in this instance?"
"Yes, exactly, and the quasar owes its luminosity to the rate at which it is feeding from this accretion disc, this material that's swirling around, like a storm, with the black hole being the eye of the storm."
"I mean, I think of it as being a bit like the muck at the bottom of your sink going down into the blender at the bottom, it's just getting chopped up, heated up, shredded, and, I mean what sort of temperatures are you talking about? What, You know, what kind of energy are you talking about being produced in this system?"
"Yes ,so the temperatures in the accretion disc easily go up to tens of thousands of degrees, but talking about brightness, the other way that we like to measure this is in terms of the luminosity of the Sun, which gives you are sense of scale. So, this quasar is about five hundred trillion times brighter than the Sun, or equivalent to about five hundred trillion suns."
"And it's been doing this sort of constantly, or for really for a long time, I mean it's just sat there, gobbling up everything around it?"
"Yeah, I mean the mass of the quasar is about 17 billion solar masses, so in order to reach that mass it has to have been feeding for a very, very long time. We work it out to be about one solar mass per day, so that's an entire Sun worth of mass every single day. Or if you like to translate that to more human terms, if you take the Earth and everybody that's on it, and you add up all of that mass together, it will eat about four of those earths, every single second."
"I suppose what I find gob-smacking about this is (a) the forces, the gravitational forces presumably involved in sweeping up that amount of material, but (b) it must be an incredibly busy place – it can't be doing this in some kind of galactic desert."
"Yes, indeed, I mean these quasars, these super-massive black holes are parts of their galaxies, right, they're always in the nuclear regions of their host galaxies, and in some way the galaxies are funnelling their material into their supermassive black hole."
"But this one must be presumably a particularly, I don't know, nutritious galaxy, I guess. It is so far away, you can't make out those kinds of details."
"We can however make out that some of that material moving around, inside the storm, round the black hole, their dynamics are such that their velocities reach up to tens of thousands of kilometres per second."
"Why are you looking for then? Is it because you just want to break records – I'm sure it's not. Or is it, that you can see these things a long way away? Is it, it tells you about the history of galaxies?"
"I mean we can learn a lot about the universe's evolution by looking at the light from the quasars. And in fact, the quasar light it tells you a lot about not just the environment that the quasar resides in, but also in anything the quasar light passes through. So, you can think of this, lights from the quasar, as a very distant beacon that illuminates information about everything and anything in between us and the quasar."
"I mean the thing that I find striking is, if I've read the numbers right, this thing is so far away that the universe was about a billion years old. I mean I suppose what I'm wondering is how did a black hole becomes so massive so early in the universe?"
"Ah see, I love this question because you are reaching to the frontier of our current understanding, this is science going as we speak. We are running into an issue now that some of these black holes are so massive that there's not enough time in the universe, at the time that we observe them to be at, in order for them to have grown to such masses as they are seen to be. We have various hypotheses for how these things have formed, but at the moment we observe it in its current state, and we have to work backwards and look into the even older universe to try to figure out how these guys came to be."
Roland Pease interviewingDr. Samuel Lai (Australian National University)
Notes
1 Having been a science teacher, I find myself listening to, or reading, science items in the media at two levels
I am interested in the science itself (of course)
I am also intrigued by how the science is presented for the audience
So, I find myself paying attention to simplifications, and metaphors, and other features of the way the science is communicated.
Teachers will be familiar with this. Curriculum selects some parts of science and omits other parts (and there is always a debate to be had about wither the right choices are made about what to include, and what to omit). However, it is rare for the selected science itself to be presented in 'raw' form in education. The primary science literature is written by specialists for other specialists, and to a large extent by researchers for other researchers in the same field – and is generally totally unsuitable for a general audience.
Curriculum science is therefore an especially designed representation of the science intended to be accessible to learners at a particular stage in their education. Acids for twelve years olds or natural selection for fifteen year olds cannot be as complex, nuanced and subtle as the current state of the topic as presented in the primary literature. (And not just because of the level f presentation suitable for learners, but also because in any live field, the work at the cutting edge will by definition be inconsistent across studies as this is just where the experts are still trying to make the best sense of the available evidence.)
The teacher then designs presentations and sequences of learning activities to engage particular classes of learners, for often teaching models and analogies and the like are needed as stepping stones, or temporary supports, even to master the simplified curriculum models set out as target knowledge. Class teaching is challenging as every learner arrives with a unique nexus of background knowledge, alternative conceptions, relevant experiences, interests, vocabulary, and so forth. Every class is a mixed ability class – to some extent. The teacher has to differentiate within a basic class plan to try and support everyone.
I often think about this when I listen to or read science journalism or popular science books. At least the teacher usually knows that all the students are roughly the same age, and have followed more-or-less the same curriculum up to that point. Science communicators working with the public know very little about their audience. Presumably they are interested enough in the topic or science more generally to be engaging with the work: but likely of a very diverse age, educational level, background knowledge: the keen ten year old to the post-doctoral researcher; the retired engineer to the autistic child with an intense fascination in every detail of dinosaurs…
I often find myself questioning some of the simplifications and comparisons used on science reports in the media – but I do not underestimate the challenge of reporting on the latest findings in some specialist area of science in an 'academically honest' way (to borrow a term from Jerome Bruner) in a three minute radio slot or 500 words in a magazine. So, in that spirit, I was fascinated by the way in which the latest research into Supernova 1987A and J0529-4351 was communicated, at least as much as the science itself.
2 That is, the flux of material emitted by our Sun, for example, is quite significant in human terms, but is minute compared to its total mass. Our sun has cooled considerably in the past few billions of years, but that's long time for it to change! (The Earth's atmosphere has also changed over the same time scale, which has compensated.)
3 Some very basic physics (Isaac Newton's law of cooling) tells us that objects radiate energy at a rate according to their temperature. Stars are (very large and) very hot so radiate energy at a high rate. An object will also be absorbing radiation – but the 'bath' of radiation it experiences depends on the temperature of its surroundings. A hot cup of coffee will cool as it is radiating faster than it is absorbing energy, because it is hotter than its surroundings. Eventually it will be as cool as the surroundings and will reach a dynamic equilibrium where it radiates and absorbs at the same rate. (Take the cooled cup of coffee into the sauna and it will actually get warmer. But do check health and safety rules first to see if this is allowed.)
The reference to how
"what eventually will happen over the lifetime of the universe is this neutron star will start to cool down, gradually and gradually and fade away. But that'll be many, many billions of years from now"
should be understood to mean that the cooling process STARTED as soon as there was no internal source of heating (form nuclear reactions or gravitational collapse) to maintain the high temperature; although the process will CONTINUE over a long period.
4 That weak attempt at humour is a variant on the story of the museum visitors who asked the attendant how old some ancient artefacts were. Surprised at the precision of the reply of "20 012 " years, they asked how the artefacts could be dated so precisely. "Well", the attended explained, "I was told they were twenty thousand years old when I started, and I've worked here for twelve years."
Many physics teachers will not find this funny at all, as it is not at all unusual for parallel mistakes to be made by students. (And not just students: a popular science book suggested that material in meteors can be heated in the atmosphere to temperatures of up to – a rather precise – 36 032 degrees! (See 'conceptions of precision').
5 The Holy Grail being the cup that Jesus is supposed to have used at the last supper to share wine with his disciples before he was arrested and crucified. Legend suggests it was also used to collect some of his blood after his execution – and that it was later brought to England (of all places) by Joseph of Arimathea, and taken to Glastonbury. The Knights of King Arthur's Round Table quested to find the Grail. It was seen as a kind of ultimate Holy Relic.
6 Greek and Roman cultures associated the planets (which for them included the Sun and Moon) with specific Gods. Many constellations were said to be living beings that have been placed in the heavens after time on earth. Personification of these bodies by referring to them in gendered ways ('he', 'she') still sometimes occurs.
In his cosmogony, Plato had the stars given a kind of soul. Whereas Aristlotle's notion of soul can be understood as being something that emerges from the complexity of organisation (in organisms), Plato did imply something more supernatural.
Do plants deceive insects by deliberately pretending to be rotting meat? (Spoiler alert. No, they do not.) [Image credits: Rafflesia – Maizal, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons; Amorphophallus titanum – ailing moose, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons; fly and beetle – by Clker-Free-Vector-Images from Pixabay]
Mysterious plants
Earlier this week I heard an episode of BBC Radio 4's 'Start the Week' programme entitled 'Mysterious Plants' 1 (which can be heard here). It is always good to hear science-related episodes of series such as this. The mysterious plants included Amorphophallus titanum2 believed to have the largest un-branched inflorescence of any plant in the world; and the parasitic genus Rafflesia, one species of which is thought to have the largest individual flowers in the world. 3
I could not help notice, however, that according to the guests, some plants are sentient beings, able to reflect on their circumstances, and to deliberately act in the world. Botanist Dr Chris Thorogood (of University of Oxford's Oxford Botanic Garden and Arboretum) described the parasitic plant Rafflesia as being 'pretty sneaky'. This is anthropomorphic, because – if taken literally – it implies deliberate behaviour.
No insects were deceived in the making of this programme
He was outdone, in this sense though, by evolutionary chemical ecologist Dr Kelsey Byers (of The John Innes Centre, Norwich) who told listeners,
"So these flies and beetles like to lay their eggs on rotting meat', and the flower goes 'oh, what if I also looked and smelled like rotting meat', or like the Amorphophallus titanum you might see at Kew Gardens for example, 'what if I also emitted heat, just like a pile of rotting meat?' …
So, what it's attracting are flies and beetles that essentially are going 'Ooh, that smells like food, that looks like food, I'm going to lay my eggs here, it's going to be great, my babies will have a great chance to survive'.
But there's, there's no food, it is deceiving them, it's basically saying 'I'm, mimicking the food, come and stay'."
Dr Kelsey Byer speaking on Radio 4
Now, I assume that Dr Byers does not intend this as a literal account of the biology discussed. In strict scientific terms, it is rather misleading
"flies and beetles like to lay their eggs on rotting meat"
I get a little uneasy when non human entities are described as liking things, as this does not reflect the subjective human experience of liking, say chocolate or Pink Floyd. But this unease probably links to the common alternative conception that students acquire in chemistry that atoms 'like' or 'want' full shells of electrons. Dr Byers could quite reasonably suggest that "flies and beetles tend to lay their eggs on rotting meat"; that their behaviour reflects a preference; and that is what 'likes' means. Fair enough.
"the flower goes 'oh, what if I also looked and smelled like rotting meat' … 'what if I also emitted heat, just like a pile of rotting meat?'…"
Now, flowers do not express themselves in language, and in any case (I'm fairly certain) do not have thoughts to potentially be expressed in language. Plato (2008) has his spokesperson Timaeus suggest that plants were "the kind of living being that…knows nothing of belief, reasoning, and intelligence". 4 So, no, plants do not do this – at least not literally.
"flies and beetles essentially are going 'Ooh, that smells like food, that looks like food, I'm going to lay my eggs here, it's going to be great, my babies will have a great chance to survive'…"
So insects are animals, and I can be less sure they do not have any kind of thought processes. (But it seems likely conscious thought requires a much more complex nervous system than that of any insect.) The 'essentially' means that Dr Byers is not suggesting they are directly expressing these ideas, but only indirectly (perhaps, those behavioural preferences again?) But I am pretty sure that even if insects could be said to 'think' at some level, they do not have formal concepts of food. I do not doubt that the fly experiences something when it eats that is different to when it is not eating, but I really doubt it is meaningful to suggest a fly has any concept of eating or can be said to 'know' when it is eating.
Surely, a fly feeding is pure instinct. It responds to cues (smell much more than sight I should think given the fly's compound eye {perhaps excellent for spotting movement, but – identifying potential meals?}, and the likely distance away that food might be found) to approach some material (without thinking, 'oh good, that smells like food!') and then further cues (greater intensity of the smell, perhaps; texture underfoot?) trigger eating, or egg laying. To be honest, I think even as a human I have sometimes behaved this way myself when distracted by a problem occupying all my conscious attention! (To clarify, that's when eating, not laying eggs.)
I do not think flies or beetles have any concept of 'babies'. I am pretty sure they do not know that egg laying is a reproductive function (even if they can be said to have any awareness that they are laying eggs), and will lead to offspring. I'm also pretty sure they are not aware of the issue of infant mortality, and that that they have a greater chance to be a grandparent if they choose the right place to lay their eggs.
The plant is deceiving the insects, it's basically saying 'I'm, mimicking the food, come and stay'.
Again, the plant is not saying anything. If does not have a notion of mimicry, and is not aware it is mimic. It does not have any notions. It is not deliberately deceiving the flies or beetles. It does not know there are flies or beetles in the world. It does not do anything deliberately.
I am not even sure it is right to say the plant deceives. You can only deceive an entity capable of being deceived. Insects are not deceived, just following instincts. The plant does not do anything to deliberately attract or entice the insects – their attraction to the plant is just a consequence of a match of the animal's instincts (not under the control of the insect), and the plant's evolved anatomy, physiology and biochemistry.
Now, as I suggested above, I am pretty sure Dr Byers knows all this (much better than me!) Perhaps this is just a habitual way of talking she has adopted to discuss her work, or perhaps she was deliberately using figurative language on this occasion to help communicate the science to a diverse radio audience. To 'make the unfamiliar familiar' the abstractconcepts of science need to be related to more familiar everyday experiences. The narrative here helps to humanise science.
This type of figurative language is anthropomorphic. That is, it treats non-humans (flowers, whole plants, insects, clouds, atoms…) as if they were human – with human cognition (concepts, deliberate conscious thinking) and motivations and emotions. Humans are part of the natural world, and the extent to which anthropomorphism distorts scientific accounts surely varies. An atom cannot be jealous. Nor a bacterium. But I would think a chimp can be.5 What about a fish?
This is a serious issue for science educators because learners often use anthropomorphic language in science lessons, and it is less clear they are doing so figuratively. They may mean this literally – and even if not, may come to habitually use this kind of language and so feel that in doing so they really they can explain phenomena 'scientifically'. But from a technical scientific perspective these are only pseudo-explanations (Taber & Watts, 2000).
So, sodium reacts with chlorine because the atoms want to fill their shells (Taber & Watts, 1996). So wrong, on so many levels, but so many students think that is the scientific account! Bacteria want to infect us, and seek to become resistant to antibiotics. And so many more examples.
The canonical biological explanation is that living things are the way they are because they have evolved to be so, through natural selection. It is natural selection that has led to insects laying eggs in conditions where they are likely to hatch – such as in rotting meat. It is natural selection that has led to some plants attracting insect pollinators by becoming similar to rotting meat – similar, that is, in how those plants are perceived within the insect's umwelt.
But lay people often tend to prefer teleological explanations because they appeal more to our own instincts. It seems that things are the way they are for a purpose: as if a plant was guided towards a new structure because there is an end point, identified from the outset, of becoming attractive to insects that will fertilise the flowers.
As humans behave deliberately and work towards goals, it is easy to transfer this familiar scheme to non-human species. Because human artefacts (the Eiffel Tower, the Pyramids, the iPhone, the international space station) have been designed and built with purposes in mind, it is easy to also see the intricate and effective structures and mechanisms of the living world as also designed with purpose in mind.
Of course, some of these biological structures can seem so unlikely to have evolved through 'chance' or 'trial and error' that many people find the canonical scientific account non-feasible. (And, it is very hard for people to conceptualise the sheer number of generations over which species have evolved.) Of course, although chance is involved, at each step there is feedback into the system: there is preferential selection of some outcomes. What 'works' is selected not so much because it works, but by virtual of it working.
Evolution is contingent – natural selection can only select the features that are 'in play' at a particular time. But which features remain in play is not just down to chance. 6 So, to adopt an analogy, natural selection is not simply a matter of chance, like a number coming up on a roulette wheel. It is more like a game of poker where the cards dealt may be at random, but one can then select which cards to keep, to build up a winning hand. 7
Darwin's book on 'various contrivances'
Darwin was very aware of this general problem, and the specific example of how it came to be that some plants need to be fertilised in very particular ways, by particular insects – and would seem to have structures so specific and well matched to their pollinators that it seems incredible they could have evolved rather than had been deliberately designed.
Darwin knew that many people found his account of evolution unconvincing in the face of the subtlety and intricacies of natural forms. He chose to study the orchids in some detail because they showed great diversity in flower structures and often seemed especially well 'designed' (with 'various contrivances') for their particular animal fertilisers. Darwin argued that all these odd structures could be understood to have slowly evolved from a common ancestor plant by myriad small modification of ancestral structures that collectively led to the wide diversification of forms (Darwin, 1862)
A difficult balance for science communicators
So, science communicators – whether teachers or journalists or scientists themselves – have a challenge here. The kind of language that is most likely to engage an audience and make science seem accessible can actually come to stand in the way of genuine understanding of the scientific principles.
I do not think that means figurative language should be completely avoided in discussing science, but it is very important to remember that an account which is intended to obviously be metaphorical may be understood literally because anthropomorphism and teleology seem to make perfectly good sense to most people.
These kinds of pseudo-explanations may not score any credit in science exams, but this way of thinking is perhaps as instinctively appealing to many humans as, say, laying eggs in rotting meat is to some insects.
Work cited:
Darwin, C. (1862) On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. London: John Murray
Plato (2008) Timaeus and Critias (Translator: Robin Waterfield).Oxford University Press, 2008.
Taber, K. S. and Watts, M. (1996) The secret life of the chemical bond: students' anthropomorphic and animistic references to bonding, International Journal of Science Education, 18 (5), pp.557-568. (Download this paper)
Taber, K. S., & Watts, M. (2000). Learners' explanations for chemical phenomena. Chemistry Education: Research and Practice in Europe, 1(3), 329-353. (Download this paper)
Notes:
1 The enticing episode description is:
"The plant Rafflesia has the world's largest flowers and gives off one of the worst scents; it's also something of a biological enigma, a leafless parasite that lives off forest vines. For the botanist Chris Thorogood, an expert in parasitic and carnivorous plants at the Oxford Botanic Garden and Arboretum, Rafflesia is also an obsession. In his book, Pathless Forest, he goes in search of this mysterious plant in some of the last wildernesses in South East Asia.
Dr Kelsey Byers is an evolutionary chemical ecologist who specialises in floral scent and its influence on the evolution of flowering plants. In her laboratory at the John Innes Centre in Norwich she studies how flowers use different smells to attract their pollinator of choice. From sweet aromas to the stink of rotting flesh, she explores how plants use con-artistry and sexual deception to thrive.
The ethnobotanist William Milliken from Kew Gardens has spent much of his career working with indigenous people in the Amazon to preserve traditional plant knowledge. Now he's focused on collecting folklore about the use of plants to treat ailments in animals in Britain. From wild garlic treating mastitis in cows, to cabbage for flatulence in dogs, he hopes to uncover a cornucopia of plant-based veterinary medicines."
2 Dr Thorogood helpfully explained that what Amorphophallus titanumactually means is 'giant distorted penis'.
Does a sunflower have large flowers?
3 Some plants have a great many flowers on the same 'head' or inflorescence. Consider the sunflower. From a distance it seems each of the flowers are large, but, on closer inspection, each inflorescence has a great many tiny individual flowers – each one able to produce pollen and be fertilised.
A bee on a sunflower collecting nectar and pollen. Each of the tiny structures is an individual flower.
A photo-essay showing sunflowers at different stages of development including close-ups of the structures can be seen here.
4 Although, to be fair, he went on to suggest that a plant "is aware only of the pleasures and pains that accompany its appetites". I would suggest, not.
5 Am I over-cautious? We assume all normal humans beings can potentially feel anger, jealousy, love, fear, etc. But actually no one really knows if anyone else has the same subjective experiences when two people report they are envious, or in love. People could be experiencing something quite different and still using the same label. (This is the qualia issue – e.g., how do I know if the experience I have of red is what you experience? This is something quite different from agreeing on which objects are red.) After all, some people find odours and flavours attractive that others find unpleasant, and the same mode of tickling can lead to quite different responses from different patients.
I think a dog could be sad, and a rabbit can be scared. But I doubt [sic, I mean really doubt] an earthworm could be proud. Unless we can decide where to draw the lines, we really have to wonder if these terms meaningfully transfer across species.
6 At the level of an individual's survival and reproduction, there is a lot of chance involved. Being in the right, or wrong, place when a mate, or a predator, appears; or when a flood, or a forest fire, happens, may have little to do with the variations in features within a population. But a slight advantage in attracting the mate or escaping the peril means that over a large population, across many generations, some features will be preferentially passed on.
7 Strictly these processes are not random, but 'near enough' for human purposes. A roulette ball is large enough to be a classical object (that is we can ignore the indeterminacy that seems to be part of quantum mechanics) so given the spin of the wheel, and the initial trajectory and entry point of the ball (and such factors as the fiction produced due to the materials involved) it is in principle possible to consider this a deterministic process. That is, particular, precise, starting conditions will lead to distinct, in principle predictable, outcomes. In practice though, no human could control the wheel and ball precisely enough to manufacture a specific outcome. It may as well not be deterministic.
Much the same is true of a pack of cards. Given the original order of the deck and a finite number of specific moves to shuffle the deck, only one new order is possible. It is however again difficult to deliberately shuffle a deck and control the new order (though perhaps not quite impossible – which is why often the person shuffling the deck invites other players to choose cuts within the process).
Sometimes in research, the methodology adopted requires randomisation (for example of individual participants to different experimental conditions) and usually such process as rolling dice or drawing blind ballots are 'good enough' even if not strictly random, as no person could control the outcomes obtained.
The World Economic Forum has been compared to a chemical reaction between disparate molecules. (A group of Kenyans in traditional dress, Apple's co-founder Steve Jobbs, former UK minister Rachel Maclean, musician and activist will.i.am, and journalist Gillian Tett – includes images accessed from Pixabay)
Analogy is a key tool in the teacher's toolbox when 'making the unfamiliar familiar'. Science teachers are often charged with presenting ideas that are abstract and unfamiliar, and sometimes it can help if the teacher can point out how in some ways a seemingly obscure notion is just like something already familiar to the learner. An analogy goes beyond a simile (which simply suggests something is a bit like something else) by offering a sense of how the structure of the 'analogue' maps onto the structure of the 'target'.
Apologies are useful well beyond the classroom. They are used by science journalists reporting on scientific developments, and by authors writing popular science books; and by scientists themselves when explaining their work to the public. But analogies have a more inherent role in science practices: not only being both used in formal scientific accounts written to explain to and persuade other scientists about new ideas, but actually as a tool in scientific discovery as a source of hypotheses.
to explain something about working memory to a chemist – but could also be used
to explain fatty acid structureto a psychologist who already knew about working memory.
So, the use of a scientific idea as the source analogue for some other target idea suggests the user assumes the audience is also familiar with the science. Therefore I deduce that Gillian Tett, journalist at the Financial Times presumably is confident that listeners to BBC Radio 4 will be familiar with the concept of chemical reactions.
Tett was discussing her experience of the annual World Economic Forum meeting that has just been held in the snow of the Swiss skiing resort of Davos, and suggested that the mixing of various politicians and industry and media and lobbyists had the potential to lead to interesting outcomes – like some kind of chemistry experiment,
"I got jammed into a room with will.i.am, the rapper, who was talking about his views for A.I., and suddenly you've got these activists standing next to somebody from some of the big tech. companies, and a government minister, and a group from Kenya, all talking about whether A.I. could actually be a tool to reduce social inequality, rather than increase it. So, it is a bit like a chemistry experiment where you take all of these ambitious, self-selecting, hustling molecules from around the world, shove them into one test-tube, apply maximum pressure, and force them to collide with each other at close quarters with no sleep, and see what kind of compounds arise."
An experiment (by definition) has uncertain results, and Tett used the analogue of the chemistry experiment to imply that the diverse mixes of people collected together at Davos could lead to unexpected outcomes – just like mixing a diverse range of substances might. Tett saw the way such diverse groups become 'jammed' into rooms in arbitrary combinations as they make their ways around the meeting as akin to increasing the pressure of a reaction mixture of arbitrary reagents. This reflects something of the popular media notion of dangerous 'scientific experiments', as carried out by mad scientists in their basements. Real scientific experiments are carried out in carefully controlled conditions to test specific hypothesis. The outcome is uncertain, but the composition of the reaction mixture is carefully chosen with some specific product(s) in mind.
The figure below represents the mapping between the analogue (a rather undisciplined chemistry experiment) and the reaction conditions experienced by delegates in the melting pot of Davos.
the World Economic Forum at Davos is like a chemical experiment because…
Inspection of my figure suggests some indiscipline in the analogy. The reaction conditions are to "apply maximum pressure, and force [the molecules] to collide with each other at close quarters with no sleep". Now this phrasing seems to shift mid-sentence,
from the analogue (the chemical experiment:"apply maximum pressure, and force [the molecules] to collide with each other")
to the target (being jammed into a room at the conference: "at close quarters with no sleep").
One explanation might be that Gillian Tett is not very good at thinking though analogies. Another might be that, as she was being interviewed for the radio, she was composing the analogy off-the-cut without time to reflect and review and revise…
Either of those options could be correct, but I suspect this shift offered some ambiguity that was deliberately introduced rhetorically to increase the impact of the analogy on a listener. Tatt ('an anthropologist by training' and Provost of King's College, Cambridge) had described the molecules anthropomorphically: just as molecules do not sleep,
they cannot be 'ambitious', as this is a human characteristic;
they are not sentient agents, so cannot be 'self-selecting'; and
nor can they 'hustle' as they have no control over their movements.
But the journalists, politicians, activists and industrialists can be described in these terms, reinforcing the mapping between the molecules and the Davos delegates. So, I suspect that whilst this disrupted the strict mapping of the analogy, it reinforced the metaphorical way in which Tett wanted to convey the sense that the ways in which the Davos meeting offered 'experimental' mixing of the reacting groups had the potential to produce novel syntheses.
Looking to check out some music videos on YouTube, and being presented with irrelevant advertisements, I was amazed to learn of a revolutionary new type of electrical heater that can potentially offer consumers vast savings on their electricity bill. Revolutionary, as the inventor, a disgraced London student, seems to have rewritten the laws of physics.
Revolutionary design: "a perpetual heating loop" (a coil of wire that can be left connected to a power supply?)
Warning. The copyright in the images included here does not belong to me. I think much the video looks like it uses stock footage, but if not, and IF the company behind this product believes they can genuinely support their claims as reported here, they may get in touch to explain why I am misguided.
I generally look to respect copyright in other's work, but I believe it is in the public interest to call out attempts to scam people through misrepresenting science in material in the public domain.
The revolutionary new design of heater is a small plug-in device which can heat up a room very quickly, and moreover it is so efficient that it does not waste energy – like those other more traditional types of heaters some people might still be using.
This technological advance:
can heat a home in 90 seconds
can save a householder thousands of pounds a year
"can warm any space at 90% less cost than conventional heating methods"
avoids any waste: "by reusing the heat it produces, so none of it is wasted"
on testing, it warmed university classrooms "from 10˚C to 21˚C in only 2 minutes"
uses "89% less energy" than regular heating systems
Wow. If not too good to be true, that would certainly help with the climate crisis by reducing electricity demands.
What is the new technology?
The video advertising this new type of heater offer some clues to its design. It begins by illustrating the "trick" which can "heat your home in 90 seconds" and "save thousands of pounds" off the Winter heating bill:
So, it seems you need to get some tea lights, and place them under a large inverted ceramic flower pot? I am pretty sure that's not going to do the 'trick'. Perhaps this was meant as some kind of metaphor…?
Reinstate Jason!
The video explains how 'Jason' "a clever student from UK, London University" creates the new type of heater because the University heating system was not functioning properly. He designed the new heater to support his classmates who were having to work in rooms at 10˚C.
When Jason refused to earn a fortune from his invention by selling the rights, the University responded within three days by expelling him. 1
Jason's professor thought his idea was revolutionary (but he may not be that up to date in his subject knowledge – most of the scientific community adopted metric units decades ago 2)
Apparently Jason achieved this scientific breakthrough by 'reverse-engineering' a standard heater. Presumably the available text books did not explain the physics of heaters (in essence, you connect (i) a piece of conducting material that can withstand heating and that has suitable resistance, to (ii) a power supply); so he had take apart heaters to find out how they worked.
Here he seems to be drawing up the specifications for his new design, helped by a sophisticated paper model.
The video shows how Jason studied circuit components called 'resistors' and found out how to read those little coloured lines on them (as children do in UK schools).
So what was revolutionary about the physics?
Of course, the manufacturers do not want to give away too many commercial secrets (even if Jason had nobler instincts), but the video does offer some clues.
Induction heating
One technique shown in the film is described as "a special device that creates a perpetual heating loop".
The special device illustrated seems to be a coil of thick copper wire, able to pass a large alternating current, which is heating a metal rod 'by induction'.
This works because the coil produces a large constantly changing magnetic field, which induces a changing e.m.f. in the rod. Now this technique only produces heating in an electrical conductor as the magnetic field cannot transfer energy to an insulator, such as air (which is not substantially influenced by the magnetic field). It seems Jason's genius must have been to somehow produce heating of ordinary air by this method. That would be the kind of breakthrough reflecting new physicsdeserving of a Nobel prize!
The dual Thomson effects
My ageing hearing told me that Jason's revolutionary design used the Joule-Thomson effect. This surprised me a little, as to my mind this technique would produce cooling, not heating. This effect can be experienced in everyday effects – such as in the material propelled from an aerosol can which often feels cold, or when noting the cold air passing out of the valve of a tyre being quickly deflated.
Energy is always conserved in all processes. The conservation of energy is one of the most fundamental principles in science, and is generally believed to be universal in its application. (Thus my annoyance at how the English National Curriculum includes a logically flawed reference to it.) When a compressed gas (such as in the tyre) is allowed to expand through a small opening it does work pushing back the surrounding air, and the temperature drops by a corresponding amount. 3
So, I was mystified at how an effect that usually produced cooling here gives the opposite effect. But then I spotted (from the kindly provided subtitles) that I (or else, the person making the subtitles?) had misheard. It seems Jason was using a different effect: 'dual Thomson' physics.
I have to confess to not being familiar with 'dual Thomson' physics. Indeed I only found a handful of references on the www through an internet search, and these referred to specialised instruments designed to detect ion velocities in high energy physics research.
I am not sure what that has to do with plug-in wall heaters, and I am pretty sure that that was not what was illustrated in the accompanying footage.
Testing the new design
A powerful device?
According to the video being pushed at viewers by YouTube, Jason "took this amazing gadget to the University and the outcomes were fantastic" where "classrooms went from 10˚C to 21˚C in only 2 minutes".
Before and after – the small device heated a classroom 11˚C in 12o seconds. Hm. (Move the slider to see the images)
Now that would be pretty impressive, as any lecturer who has arrived in a cold teaching room and then dragged in the electric heater from their office would know (I write from experience).
We are not told the size of the room used in this supposed trial but a lecture room would be something of the order of a thousand cubic metres. If we assume that the heater transfers all of its energy to the air in the room (and that in the short time it is used, none of this heat is lost to outside, or warms up anything else in the room – like the furnishings or the walls or ceilings – or the people who were feeling too cold) then we can calculate the energy needed, and so the power of the heater. My-back-of-the-envelope calculation suggests this would be about 100 kW. 4
Now I am not going to claim that a hundred kilowatts heater cannot be made, but I am prepared to suggest that no technology available today could safely get near, anywhere near, this power rating with this scale of device.
Larger heaters designed for industrial use are available rated for a few kilowatts, but a 100 kW plug-in heater for domestic use seems fantasy. (Especially as "You can move it around without worrying about burning yourself" according to the website.)
Am I wrong? TechTrends, the website selling the devices (sorry, independently assessing, 😉, 😉, the devices and telling us where to buy them), does not seem to offer any details on this testing, so I assume it was not carried out by competent investigators and reported in a peer reviewed journal. If indeed, given the non-viability of the claim, it really took place. Anyone reading this form TechTrends – if I am wrong please enlighten us? (Comments welcome below.)
Greater efficiency?
We are asked to accept this magical outcome because the device is so energy efficient (that in itself I believe – I expect an electric heater to be very efficient), compared with standard technology. The video claims that the new heater "used 89% less energy" than "regular heating systems". That is clearly nothing other than an outright lie!
Feel the difference – almost 90% apparently (Move the slider to see the images)
Many machines are inefficient in the sense that the energy input does not match the desired work output as some energy is 'lost' or perhaps better 'diverted'. Now energy is always conserved, so this means that, say, 100 Joules of energy are 'taken' from some supply to power some activity, but perhaps only 6oJ does what we intend (so in this case, 60% efficiency) and the other 40J has some other effect.
A key idea in thermodynamics is that engines have an inherent limit to efficiency. A car engine exhausting into the atmosphere well above absolute zero (at around 300K rather than 0K) will necessarily only direct a fraction of the energy sourced into the desired locomotion. Achieving higher temperatures in the engine (a technical challenge) can improve what is possible; but only releasing exhaust gases at 0K would make 100% efficiency even theoretically possible. So, is it feasible that normal electrical heaters would be so inefficient?
Filament lamps are only inefficient in the Summer
…or…
Why would anyone manufacture a light bulb completely encased in a solid metal shade?
The notion that a standard electric heater might be no more than 11% efficient might not sound too unlikely to some people watching these commercials as they wait for their music videos (or cats juggling, or whatever their taste may be). One reason filament lamps have been phased out is because they were notoriously inefficient – indeed, 11% efficiency is the kind of figure that was sometimes quoted. A 100 W filament lamp might only be generating visible light at around 11W, which seems quite a waste (especially as the utility company will be billing for all 100W).
I have always considered such lamps to be inefficient in the Summer, but that this is less of an issue in the Winter. That's because that other 89W will be heating up the room – unhelpful or even problematic in Summer, but perhaps acceptable in Winter when we are deliberately heating the rooms anyway. Does it matter if a little more of your heating comes from the light bulbs and a little less from the 'heaters'.
Indeed, when I was a child, before the days when most people had central heating, we used to have a device that was basically a light bulb inside a big metal shield. When turned on, it emitted no light. The bulb did, of course, but not the device. These were used on Winter evenings as bed warmers to avoid getting into a very cold bed. The lamp may have given out 11% light, but it all ultimately got absorbed into the metal and contributed to the heat transfer from filament to bed warmer and so onto the bedding. 5
Generally, energy inefficiencies in machines involve energy released as heat that goes to make molecules move about a bit faster on average rather than going where intended to do useful jobs. We might think of heat (or strictly, the dispersed thermal energy of matter, that heat leads to) as the lowest quality form of energy, that all other forms of energy are ultimately, eventually, degraded into.
This unintended 'heat leakage' may be an issue in lamps and motors and televisions and many other devices – but clearly not in heaters.
The same old hot air…
The video suggests one feature of the revolutionary new design is that instead of only heating cold air, the promoted device is able to recycle warm air to minimise waste. What could this mean?
Now if you take an electric heater out into the garden on a cold day when there is a breeze, then it is quite likely that the air that passes through the heater will be blown away quite quickly, and so the heater is always heating air from the same ambient starting point. That would be a bit of a waste. (Hint: do not use an electric heater to keep you warm in the garden – put on warm clothes or move around instead).
Inside a well insulated room, the air that is passing through the heater will soon already have been warmed, so the heater can achieve a higher room temperature for the same power input (compared with when it is operating in your garden, that is). I do not think any reasonable reading of 'standard system' for home heating would not "recycle warm air" rather that continuously heating only cold air, so to my reading this is simply a clear lie.
Some made up numbers from the website 'reviewing' (actually, promoting) the device
90% less cost to the householder?
I therefore consider the claim that the new design of heater "can warm any space at 90% less cost than conventional heating methods" is also a simple lie. Your standard home plug-in heater might not be as well designed, and may have some flaws, but it will not be converting 89 0r 90% of the energy supply into something other than heat. Inefficient machines produce heat instead of other (generally more useful) forms of output.
No, it cannot.
Not unless we've had some basic physics completely wrong for a long time and no one had noticed.
As has been often pointed pointed out, any claim that begins "in fact…" should be treated suspiciously. There is no logical difference between writing
"these claims are inconsistent with the laws of physics", and
"in fact, these claims are inconsistent with the laws of physics"
'In fact' tends to be used rhetorically when what is being said might of itself not seem a very convincing 'fact', and could otherwise be surprising, as in,
"in fact, Albert Einstein never actually found physics interesting"
In fact, this is another lie.
The video directs readers to what seems at first sight to be a consumer website praising the new heaters, although they've dropped the story about poor, mistreated Jason,
"This simple but rather genius concept was developed in 2019 by a group of electrical engineers from the EVI (Electric Vehicle Industry)."
There seem to be at least two versions directing to the same basic copy promoting 'EcoWell' and 'HeatFlow' on different webpages. Some customers (such as a 'Daniel Walker') seem to have even sought out both designs, presumably to match their decor in different rooms?
The web-pages do not repeat the more obviously fraudulent claims, but rather seem to suggest the heater is going to save money by pointing out how much heat produced by a domestic heating system is leaving the home. This is important, but it is worth n0oting that (assuming that a house can never have perfect thermal insulation) then when the home has reached a constant temperature (and the external temperature is not changing), the amount of heat being lost to the environment matches that produced by the heaters. That is, 100% of the energy being used for heating is being transferred to the outside. It is important to try to slow that rate, but all heating systems, "leak energy, warming up basements and underground lines", not just those that are "outdated and inefficient" as the TechTrends website implies.
It still claims that "99.8% efficiency ensures all your electricity gets turned into heat, saving you thousands" (where any heater will be highly efficient at producing heat – the issue is how it is distributed), but acknowledges.
"One HeatFlow heater can heat up a room up to 12 square meters. Depending on your needs, you might want to purchase several heaters for continuous warmth in all rooms or keep one to bring with you where you need it the most."
"One EcoWell heater can heat up a room up to 12 square meters. Depending on your needs…"
(The EcoWell design looks very similar to an alternative available from a well-established and reputable manufacturer selling their product on Amazon at £20 when I checked today. Whereas TrechTrends tells readers that with the half price discount "At the moment of writing this review, you can get EcoWell[*] for just £49.99!" [* or HeatFlow if you prefer the tiny coal fireplace look]
So, if you stop heating the house, and just have one single plug-in device that you move around to the room that you are going to be occupying, it will save money on your energy bills. But that will not work if you like frequently moving between rooms in your house, or have a family that like some privacy. (Of course, you can save even more money on your bills by wearing a good many layers of clothing and not using any heaters. )
Still, the website shows there have been many favourable customers' comments, which I rather spoiled yesterday with my own cynical offering:
But that was yesterday, and checking back today I was un-amazed to find my comment wiped. In any case, there is an acknowledgement showing the site is an advert, and the photos are of 'models' not real purchasers:
But it is presented in faint text on a black background seemingly designed to make sure it is not easily noticed 6 .
There is of course a special price if you buy now within 24 hours…
As there was yesterday.
Does it matter?
So these advertisements contain some very misleading 'bad science' (or, perhaps – as the claims are inconsistent with well-studied science – magical claims). Misinformation like this is is common in the post-truth age – but here it is masquerading as engineering and physics.
Anyone who has been to school and benefited from science education should not be taken in by the sillier claims about this new design of heater. They may be very useful, compact, convenient, and perhaps even powerful-for-their-size heaters. But the more extreme claims being made are lies, contrary to basic physics.
They cannot heat a classroom in 2 minutes. They are not 97% more cost effective. They will not save people thousands of pounds if used to replace other plug-in heaters. They do not use induction (or tea lights) to heat the air or dual Thomson physics. And although they recycle hot air, so does every other type of room heater. They may well be over 99% efficient, but that's because heat is the lowest grade of energy and so increasing machine efficiency is about avoiding 'high grade' energy being reduced to heat. The claim here is like claiming your teenager is better than the standard model because it can turn an organised bedroom into arbitrarily organised chaos – as if that was a rare quality, given that most teenagers are only ever able to mess up part of a room.
The video is in breach of UK law and YouTube should have done due diligence before accepting advertising money for such deliberately dishonest films. I feel somewhat offended that YouTube would think that an educated person would fall for this – but presumably plenty do. If people are listening to/watching this nonsense and not spotting a problem, then science education has not done a very good job. This kind of scam relies on low levels of scientific literacy.
But, I suspect these companies are getting plenty of sales from their dishonest advertising as in October 2022 I wrote to the Advertising Standards Authority (ASA) to complain about very similar adverts:
"Brand/product:AlphaHeater or Elite Heat
Your complaint: After watching a football match on you tube there was a misleading video, which directed viewers to a misleading website. The video claimed that a revolutionary new heater using jet engine technology would heat a room "using 90% less energy" (screen shot below). This is nonsense (I am a Chartered Physicist, Fellow of the Institute of Physics: heat is the lowest quality form of heat, so (unlike say the working of a motor) a heater cannot be produced so much more more efficiently.). The website was pretending to be an independent review (HeatReviewGuide) of the heater but had dummy links and was only advertising that product (see below). …
Acknowledgement of complaint: October 2022
seems familiar?
The ASA replied
"Thank you for contacting the Advertising Standards Authority (ASA) about ads online for this heating device and for your patience while your complaint was considered.
We acknowledge your concern about this ad and so we have put an alert out to have it taken down through our ASA Scam Ad Alert System. We will share the details of this ad with our network of key industry partners, including all the major social media platforms and ad networks operating in the UK, so that the content is taken down and to help stop similar ads appearing in future."
Outcome of compliant: November 2022
I guess criminals behind these scams respond to this regulation of advertisements by changing the name or other minor details of their products, and then just carrying on. Time for another message to the ASA?
Merry Christmas everyone.
Notes
1 Even if we believe that Universities still readily expel fee-paying 'customers' for the most vile of offences, and even if we think that refusing to become a billionaire amounts to grounds for such an expulsion (why?) – the idea that a university could act in three days on a student disciplinary matter and follow due process does not ring true. (I know from personal experience there are plenty of people in universities who are prepared to ignore principles of natural justice, but luckily the institutions themselves have careful and balanced procedures to protect members from false and malicious claims). Jason could always have got his University's Enterprise department to help him arrange the commercialisation of the design, and then signed over any personal interests to generate income for a charitable trust.
2 I am assuming that psi means pounds per square inch. The scientific units are pascals (that is newtons per square metre) which were already been taught in school when I was a pupil half a century ago.
3 Temperature is NOT the same as heat, of course, but a certain temperature change in a sample of a substance involves the transfer of a related amount of energy that for a characterised material can be calculated (heat = product of mass by specific heat capacity by temperature change; 𝚫H = mc𝛉).
4 I used:
The density of air is about 1200 grammes per cubic metre
the specific heat capacity of air is about 1 Jg-1K-1
power = energy transferred / time [= 120s]
5 We usually think of light and heat as discrete. But heating is energy transferred due to a difference in temperature: so when radiation is emitted by a hot body and absorbed by a colder one it counts as heat, even if it is light. So heat is not necessary light, but light often counts as heat. As they say, there's often 'more heat than light'.
6 Just in case you are finding the text difficult to make out, it reads:
"THIS IS AN ADVERTISEMENT AND NOT AN ACTUAL NEWS ARTICLE, BLOG, OR CONSUMER PROTECTION UPDATE
ADVERTISING DISCLOSURE: THIS WEBSITE AND THE PRODUCTS & SERVICES REFERRED TO ON THE SITE ARE ADVERTISING MARKETPLACES. THIS WEBSITE IS AN ADVERTISEMENT AND NOT A NEWS PUBLICATION. ANY PHOTOGRAPHS OF PERSONS USED ON THIS SITE ARE MODELS. THE OWNER OF THIS SITE AND OF THE PRODUCTS AND SERVICES REFERRED TO ON THIS SITE ONLY PROVIDES A SERVICE WHERE CONSUMERS CAN OBTAIN AND COMPARE."
Does the medieval notion of the human body as a microcosm of the wider Cosmos – in which is played out an eternal battle between good and evil – still influence our thinking?
Keith S. Taberwants to tell you a story
Are you sitting comfortably?
Good, then I will begin.
Once upon a time there was an evil microbe. The evil microbe wanted to harm a human being called Catherine, and found ways for his vast army of troops to enter Catherine's body and damage her tissues. Luckily, unbeknown to the evil microbe, Catherine was prepared to deal with invaders – she had a well-organised defence force staffed by a variety of large battalions, including some units of specialist troops equipped with the latest anti-microbe weapons. There were many skirmishes, and then a series of fierce battles in various strategic locations – and some of these battles raged for days and days, with heavy losses on both sides. No prisoners were taken alive. Many of Catherine's troops died, but knowing they had sacrificed themselves for the higher cause of her well-being. But, in the end, all of the evil microbe's remaining troops were repelled and the war was won by the plucky defenders. There was much rejoicing among the victorious army. The defence ministry made good records of the campaign to be referred to in case of any future invasions, and the surviving soldiers would long tell their stories of ferocious battles and the bravery of their fallen comrades in defeating the wicked intruders. Catherine recovered her health, and lived happily ever after.
There is a myth, indeed, perhaps even a fairy story, that is commonly told about microbial disease and immunity. Disease micro-organisms are 'invaders' and immune cells are 'defenders' and they engage in something akin to warfare. This is figurative language, but has become so commonly used in science discourse that we might be excused for forgetting this is just a stylistic feature of science communication – and so slip into habitually thinking in the terms that disease actually is a war between invading microbes and the patient's immune system.
Immunity is often presented through a narrative based around a fight between opposed sentient agents. (Images by Clker-Free-Vector-Images and OpenClipart-Vectors from Pixabay.)
Actually this is an analogy: the immune response to infection is in some waysanalogous to a war (but as with any analogy, only in some ways, not others). As long as we keep in mind this is an analogy, then it can be a useful trope for talking and thinking about infectious disease. But, if we lose sight of this and treat such descriptions as scientific accounts, then there is a danger: the myth undermines core biological principles, such that the analogy only works if we treat biological entities in ways that are contrary to a basic commitment of modern science.
In this article I am going to discuss a particular, extensive, use of the disease-as-war myth in a popular science book (Carver, 2017), and consider both the value, and risks, of adopting such a biological fairy-tale.
Your immune system comprises a vast army of brave and selfless soldiers seeking to protect you from intruders looking to do you harm: an immune response is a microcosm of the universal fight between good and evil?
A myth is a story that has broad cultural currency and offers meaning to a social group, usually involving supernatural entities (demons, superhuman heroes, figures with powerful magic), but which is not literally true.
Carver's account of the immune system
I recently read 'Immune: How your body defends and protects you' (henceforth, 'Immune') by Catherine Carver. Now this is clearly a book that falls in the genre 'popular science'. That is, it has been written for a general audience, and is not meant as a book for experts, or a textbook to support formal study. The publishers, Bloomsbury, appropriately describe Carver as a 'seasoned science communicator'. (Appropriately, as metaphorical dining features strongly in the book as well.)
Carver uses a lot of contractions ("aren't", "couldn't", "doesn't", "don't", "isn't", "it's", "there's", "they're", "we've", "what's", "who'd", "wouldn't", "you'd") to make her writing seem informal, and she seems to make a special effort to use metaphor and simile and to offer readers vivid scenes they can visualise. She offers memorable, and often humorous, images to readers. A few examples offer an impression of this:
"…the skin cells…migrate through the four layers of the epidermis, changing their appearance like tiny chameleons…"
"Parietal cells dotted around the surface of the stomach are equipped with proton pumps, which are like tiny merry-go-rounds for ions."
"a process called 'opsonisation' make consuming the bacterial more appealing to neutrophils, much like sprinkling tiny chocolate chips on a bacterial cookie."
"The Kupffer cells hang around like spiders on the walls of the blood vessels…"
In places I wondered if sometimes Carver pushed this too far, and the figurative comparisons might start to obscure the underlying core text…
"…the neutrophil…defines cool. It's the James Dean of the immune system; it lives fast, dies young and looks good in sunglasses."
Carver, 2017, p.7
"The magnificence of the placenta is that it's like the most efficient fast-food joint in the world combined with a communications platform that makes social media seem like a blind carrier pigeon, and a security system so sophisticated that James Bond would sell his own granny to the Russians just to get to play with it for five minutes."
Carver, 2017, p.113
When meeting phrases such as these I found myself thinking about the metaphors rather than what they represented. My over-literal (okay, pedantic) mind was struggling somewhat to make sense of a neutrophil in (albeit, metaphoric) sunglasses, and I was not really sure that James Bond would ever sell out to the Russians (treachery being one of the few major character faults he does not seem to be afflicted by) or be too bothered about playing with a security system (his key drives seem focused elsewhere)…
…but then this is a book about a very complex subject being presented for an audience that could not be assumed to have anything beyond the most general vague prior knowledge of the immune system. As any teacher knows, the learner's prior knowledge is critical in their making sense of teaching, and so offering a technically correct account in formal language would be pointless if the learner (or, here, reader) is not equipped to engage at that level.
'Immune' is a fascinating and entertaining read, and covers so much detailed ground that I suspect many people reading this book would would not have stuck with something drier that avoided a heavy use of figurative language. Even though I am (as a former school science teacher *) probably not in the core intended audience for the book, I still found it very informative – with much I had not come across before. Carver is a natural sciences graduate from Cambridge, and a medical doctor, so she is well placed to write about this topic.
Catherine Carver's account of the immune system is written to engage a popular readership and draws heavily on the disease-as-war analogy.
My intention here is not to offer a detailed review or critique of the book, but to explore its use of metaphors, and especially the common disease-as-war theme (Carver draws on this extensively as a main organising theme for the book, so it offers an excellent exemplar of this trope) – and discuss the role of the figurative language in science communication, and its potential for subtly misleading readers about some basic scientific notions.
The analogy
The central analogy of 'Immune' is clear in an early passage, where Carver tells us about the neutrophil,
"…this cell can capture bubonic plague in a web of its own DNA, spew out enzymes to digest anthrax and die in a kamikaze blaze of microbe-massacring glory. The neutrophil is a key soldier in an eternal war between our bodies and the legions of bacteria, viruses, fungi and parasites that surround us. From having sex to cleaning the kitchen sink, everything we do exposes us to millions of potential invaders. Yet we are safe. Most of the time these invaders' attempts are thwarted. This is because the human body is like an exceedingly well-fortified castle, defended by billions of soldiers. Some live for less than a day, others remember battles for years, but all are essential for protecting us. This is the hidden army that we all have inside of us…"
Carver, 2017, p.7
Phew – there is already a lot going on there. In terms of the war analogy:
We are in a perpetual war with (certain types) of microbes and other organisms
The enemy is legion (i.e., has vast armies)
These enemies will invade us
The body is like a well-protected fort
We have a vast army to defend us
There will be battles between forces from the two sides
Some of our soldiers carry out suicide (kamikaze) missions
Our defenders will massacre microbes
We (usually) win the battles – our defences keep us safe
Some of these specific examples can be considered as metaphors or similes in they own right when they stand alone, but collectively they fit under an all-encompassing analogy of disease-as-war.
But this is just an opening salvo, so to speak. Reading on, one finds many more references to the 'war' (see Boxes 1 and 2 below).
The 'combatants' and their features are described in such terms as army, arsenals, assassins, band of rebels, booby-traps, border guards, border patrol force, commanders, defenders, fighting force, grand high inquisitors, hardened survivor, invaders, lines of defence, muscled henchman, ninjas, soldiers, terminators, trigger-happy, warriors, and weapons.
Disease and immune processes and related events are described in terms such as alliance, armoury, assassination campaign, assault, assault courses, attack, battlefield, bashing, battles, boot camp, border control, calling upsoldiers, chemical warfare, cloaking device, craft bespoke weaponry, decimated, dirty bomb, disables docking stations, double-pronged attack, exploding, expose to a severe threat,fight back, fighting on fronts, friendly fire, go on the rampage, hand grenades, heat-seeking missiles, hold the fort, hostile welcome, instant assault , kamikaze, killer payload, massacring, patrolling forces, pulling a pin on a grenade, R & R [military slang for 'rest and recuperation'], reinforcing, security fence, self-destruct, shore updefences, slaughters/slaughtering, smoke signals, standing down, suicidal missions, Swiss army knife, taking on a vast army on its home turf, throwing dynamite, time bomb, toxic cloud, training camp, training ground, trip the self-destruct switch, Trojan horse, victories, war, and wipe out the invader.
Microbes and cells as agents
A feature of the analogue is that war is something undertaken by armies of soldiers, that are considered as having some level of agency. The solder is issued with orders, but carries them out by autonomous decision-making informed by training as well as by conscience (a soldier should refuse to obey an illegal order, such as to deliberately kill civilians or enemy combatants who have surrendered). Soldiers know why they are fighting, and usually buy into at least the immediate objectives of the current engagement (objectives which generally offer a more favourable outcome for them than for the enemy soldiers). A soldier, then, has objectives to be achieved working towards a shared overall aim; purposes that (are considered to) justify the actions taken; and indeed takes deliberate actions intended to bring out preferred outcomes. Sometimes soldiers may make choices they know increase risks to themselves if they consider this is justified for the higher 'good'. These are moral judgements and actions in the sense of being informed by ethical values.
An extensive range of terminology related to conflict is used to describe aspects of disease and the immune response to infection. (Image sources: iXimus [virus], OpenClipart-Vectors [cell], Tumisu [solders in 'Raising the Flag on Iwo Jima'-like poses], from Pixabay.)
Now, I would argue that none of this applies to either disease organisms nor components of a human immune system. Neither a bacterium nor an immune cell know they are in a war; neither have personal, individual or shared, objectives; and neither make deliberate choices about actions to take in the hope they will lead to particular outcomes. No cell knowingly puts itself at risk because it feels a sacrifice is justified for the benefit of its 'comrades' or the organism it is part of.
So, all of this might be considered part of what is called the 'negative analogy', that is, where the analogy breaks down because the target system (disease processes and immune responses) no longer maps onto the analogue (a war). Perhaps this should be very obvious to anyone reading about the immune system? At least, perhaps scientists might assume this would be very obvious to anyone reading about the immune system?
Now, if we are considering the comparison that an immune response is something like a nation's defence forces defending its borders against invaders, we could simply note that this is just a comparisonbut one where the armies of each side are like complex robotic automatons pre-programmed to carry out certain actions when detecting certain indicators: rather than being like actual soldiers who can think for themselves, and have strategic goals, and can rationally choose actions intended to bring about desired outcomes and avoid undesired ones. (A recent television advertising campaign video looking to recruit for the British Army made an explicit claim that the modern, high-tech, Army could not make do with robots, and needed real autonomous people on the battlefield.)
However, an account that relies too heavily on the analogy might be in danger of adopting language which is highly suggestive that these armies of microbes and immune cells are indeed like human soldiers. I think Carver's book offers a good deal of such language. Some of this language has already been cited.
Immune cells do not commit kamikaze
Consider a neutrophil that might die in a kamikaze blaze of microbe-massacring glory. Kamikaze refers to the actions of Japanese pilots who flew their planes into enemy warships because they believed that, although they would surely die and their planes be lost, this could ensure severe damage to a more valuable enemy resource – where the loss of their own lives was justified by allowing them to remain at the plane's controls until the collision to seek to do maximum damage. Whatever we think of war in general, or the Kamikazi tactics in particular, the use of this term alludes to complex, deliberate, human behaviour.
Immune cells do not carry out massacres
And the use of the term massacre is also loaded. It does not simply mean to kill, or even to kill extensively. For example, the Jallianwala Bagh massacre, or Amritsar massacre, is called a massacre because (British) soldiers with guns deliberately fired at, with intent to kill or seriously injure, a crowd of unarmed Indians who were in their own country, peacefully protesting about British imperial policies. The British commanders acted to ensure the protesters could not easily escape the location before ordering soldiers to fire, and shooting continued despite the crowd trying to flee and escape the gunfire. Less people died in the Peterloo Massacre (1819) but it is historically noteworthy because it represented British troops deliberately attacking British demonstrators seeking political reform, not in some far away 'corner of Empire', but in Manchester.
Amritsar occurred a little over a century ago (before modern, post-Nurenmberg, notions of the legality of military action and the responsibility of soldiers to not always follow orders blindly), but there are plenty of more recent examples where the term 'massacre' is used, such as the violent clearing of protesters in Tiananmen Square in 1989 and the Bogside 'Bloody Sunday' massacre in 1972 (referenced in the title of the U2 song, 'Sunday Bloody Sunday'). In these examples there is seen to be an unnecessary and excessive use of force against people who are not equipped to fight back, and who are not shown mercy when they wish to avoid or leave the confrontation.
'Monument in Memory of Chinese from Tiananmen in Wrocław, Poland' commemorating the massacre of 4th June 1989 when (at least) hundreds were killed in Beijing after sections of the People's Liberation Army were ordered to clear protesters from public places (Masur, Public domain, via Wikimedia Commons)
The term massacre loses its meaning without this sense of being an excessively immoral act – and surely can only apply to an action carried out by 'moral agents' – agents who deliberately act when they should be aware the action cannot be morally justified, and where they can reasonably see the likely outcomes. (Of course, it is more complicated that this, in particular as a soldier has orders as well as a conscience – but that only makes the automatic responses of immune cells towards pathogens even less deserving of being called a massacre.)
The term moral agent does not mean someone who necessarily behaves morally, but rather someone who is able to behave morally (or immorally) because they can make informed judgements about what is right and wrong – they can consider the likely consequence of their actions in terms of a system of values. An occupied building that collapses does harm to people, but cannot be held morally responsible for its 'behaviour' in the way a concentration camp guard or a sniper can be. A fox that takes a farmer's chickens has no conception of farming, or livestock, or ownership, or of the chickens as sentient beings that will experience the episode from a different perspective, but just acts instinctively to access food. Microbes and cells are like the building or the fox, not the guard or the sniper, in this respect.
Moreover, in the analogue, the massacred are also moral agents: human beings, with families, and aspirations for their futures, and the potential for making unique contributions to society… I am not convinced that bacteria or microbes are the kinds of entities that can be massacred.
Anthropomorphic references
Carver then writes about the immune system, or its various components, as well as various microbes and other pathogenic organisms, as though they are sentient, deliberative agents acting in the world with purposes. After all, wars are a purely human phenomenon.1 Wars involve people: people with human desires, motives, feelings, emotions, cunning, bravery (or not), aims and motivations.
Anthropomorphism is describing non-human entities as if they are people. Anthropomorphism is a common trope in science teaching (and science communication) but learners may come to adopt anthropomorphic explanations (e.g., the atom wants…) as if they are scientific accounts (Taber & Watts, 1996).
Bacteria, body cells and the like are not these kinds of entities, but can be described figuratively as though they are. Consider how,
"Some bacteria are wise to this and use iron depletion as an indicator that they are inside an animal. Other bacteria have developed their own powerful iron-binding molecules called 'siderophores' which are designed to snatch the iron from the jaws of lactoferrin. Perhaps an even smarter strategy is just to opt out of the iron wars altogether…
…tear lipocalin, whose neat structure includes a pocket for binding a multitude of molecules. This clever pocket allows tear lipocalin to bind the bacterial siderophores…neutralising the bacterium's ability to steal iron from us…"
Carver, 2017, pp.20-21
Of course, bacteria are only 'wise' metaphorically, and they only 'develop' and 'design' molecules metaphorically, and they only adopt 'smarter strategies' or can 'opt out' of activities metaphorically – and as long as the reader appreciates this is all figurative language it is unproblematic. But, when faced with multiple, and sometimes extended, passages seeming to imply wise and clever bacteria developing tools and strategies, could the reader lose sight of this (and, if so, does that matter?)
If bacteria are not really clever, nor are pockets (or 'pockets' – surely this is a metaphor, as actual pockets are designed features not evolved ones). Stealing is the deliberate taking of something one knows is owned by someone else. Bacteria may acquire iron from us, but (like the fox) they do not stealas they have no notion of ownership and property rights, nor indeed, I suggest, any awareness that those environments from which they acquire the iron are considered by them[our]selves as 'us'.
That is, there is an asymmetrical relationship here: humans may be aware of the bacteria we interact with (although this has been so only very recently in historical terms) but it would be stretching credibility to think the bacteria have any awareness – even assuming they have ANY awareness in the way we usually use the term – of us as discrete organisms. So, the sense in which they "use iron depletion as an indicator that they are inside an animal" cannot encompass a deliberate use of an indicator, nor any inference they are inside an animal. There is simply a purely automatic, evolved, process that responds to environmental cues.
I have referred in other articles posted here to examples of such anthropromorphic language in public discourse being presented apparently in the form of explanations: e.g.,
My focus here is Catherine Carver's book, but it is worth bearing in mind that even respectable scientific journals sometimes publish work describing viruses in such terms as 'smart', 'nasty', 'sneaky' – and, especially it seems, 'clever' (see 'So who's not a clever little virus then?'). So, Carver is by no means an outlier or maverick in using these devices.
'Immune' is embellished throughout with this kind of language – language that suggests that parasites, microbes, body cells, or sometimes even molecules:
act as agents that are aware of their roles and/or purposes;
do things deliberately to meet objectives;
have preferences and tastes.
The problem is, that although this is all metaphorical, as humans we readily interpret information in terms of our own experiences, so a scientific reading of a figurative text may requires us to consciously interrogate the metaphors and re-interpret the language. Historians of chemistry will be well aware of the challenge from trying to make sense of alchemical texts which were often deliberately obscured by describing substances and processes in metaphoric language (such as when the green lion covers the Sun). Science communicators who adopt extensive metaphors would do well to keep in mind that they can obscure as well as clarify.
For example, Carver writes:
"…the key to a game of hide and seek is elementary: pick the best hiding place. In the human body, the best places to hide are those where the seekers (the immune system) find it hard to travel. This makes the brain a very smart place for a parasite to hide."
Carver, 2017, p.132
'There is a strong narrative here ("the eternal game of hide and seek [parasites] play with us")- most of us are familiar with the childhood game of hide and seek, and we can readily imagine microbes or parasites hiding out from the immune cells seeking them. This makes sense, because of course, natural selection has led to an immune system that has components which are distributed through the body in such a way that they are likely to encounter any disease vectors present – as this increases fitness for the creature with such a system – and natural selection has also led to the selection of such vectors that tend to lodge in places less accessible to the immune cells – as this increase fitness of the organism that we2 consider a disease organism. Thus evolution has often been described, metaphorically, as an arms race.
But this is not really a game(which implies deliberate play – parasites can not know they are playing a game); and the disease vectors do not have any conception of hiding places, and so do not pick where to go accordingly, or using any other criterion; the immune cells are not knowingly seeking anything, and do not experience it being harder to get to some places than others (they are just less likely to end up in some places for purely naturalistic reasons).
So, a parasite that ends up in the brain certainly may be less accessible to the immune system, but is not deliberately hiding there – and so is no more 'smart' to end up there than boulders that congregate at the bottom of a mountainside because they think it is a good place to avoid being sent rolling by gravity (and perhaps having decided it would be too difficult to ascend to the top of the mountain).4
It is not difficult to de-construct a text in the way I have done above for the hide-and-seek comparison- if a reader thinks this is useful, and consequently continually pauses to do so. Yet, one of the strengths of a narrative is that it drives the reader forward through a compelling account, drawing on familiar schemata (e.g., hide and seek; dining; setting up home…) that the reader readily brings to mind to scaffold meaning-making.
Another familiar (to humans) schema is choosing from available options:
"…the neutrophil's killer skills come to the fore…It only has to ask one question: which super skills should be deployed for the problem at hand?"
Carver, 2017, p.27
So, it seems this type of immune cell has 'skills', and can pose itself (and answer) the question of which skills will be most useful in particular circumstances (perhaps just like a commando trained to deal with unexpected scenarios that may arise on a mission into enemy-held territory?) Again, of course, this is all figurative, but I wonder just how aware most readers are of this as they read.
Carver's account of Kupffer cells makes them seem sentient,
"The Kupffer cells hang around like spiders on the walls of the blood vessels waiting to catch any red blood cells which have passed their best before date (typically 120 days). Once caught, the red blood cell is consumed whole by the Klupffer cell, which sets about dismantling the haemoglobin inside its tasty morsel."
Carver, 2017, p.27
Kupffer cells surely do not 'hang around' or 'wait' in anything more than a metaphorical sense. If 'catching' old red blood cells is a harmless metaphor, describing them as tasty morsels suggests something about the Kupffer cells (they have appetites that discriminate tastes – more on that theme below) that makes them much more like people than cells.
Another striking passage suggests,
"Some signals are proactive, for example when cells periscope from their surface a receptor called ULBP (UL16-binding protein). Any NK cell that finds itselfshaking hands with a ULBP receptor knows it has found a stressed-out cell. The same is true if the NK cell extends its receptors to the cell only to find it omits parts of the secret-handshakeexpected from a normal cell. Normal, healthy cells display a range of receptors on their surface which tell the world 'I'm one of us, everything is good'. Touching these receptors placates NK cells, inhibiting their killer ways. Stressed, infected cells display fewer of these normal receptors on their surface and in the absence of their calming presence the trigger-happy NK cells attack."
Carver, 2017, p.27
That cells can 'attack' pathogens is surely now a dead metaphor and part of the accepted lexicon of the topic. But cells are clearly only figuratively telling the world everything is good – as 'telling' surely refers to a deliberate act. The hand-shaking, including the Masonic secret variety (n.b., a secret implies an epistemic agent capable of of knowing the secret), is clearly meant metaphorically – the cell does not 'know' what the handshake means, at least in the way we know things.
If the notion of a cell being stressed is also a dead metaphor (that is 'stressed' is effectively a technical term here {"the concept of stress has profitably been been exported from physics to psychology and sociology" Bunge, 2017/1998}), a stressed-out cell seems more human – perhaps so much so that we might be subtly persuaded that the cell can actually be placated and calmed? The point is not that some figurative language is used: rather, the onslaught (oops, it is contagious) of figurative language gives the reader little time to reflect on how to understand the constant barrage of metaphors…
"…it takes a bit of time for the B cells to craft a specific antibody in large quantities. However the newly minted anti-pollen antibodies are causing mischief even if we can't see evidence of it yet. They travel round the body and latch on to immune cells called masts anywhere they can find them. This process means the person is now 'sensitised' to the pollen and the primed mast cells lie in wait throughout the body…"
Carver, 2017, pp.183-184
…so, collectively the language can be insidious – cells can 'craft' antibodies (in effect, complex molecules) which can cause mischief, and find mast cells which lie in waitfor their prey.
Sometimes the metaphors seemed to stretch even figurative meaning. A dying cell will apparently 'set its affairs in order'. In humans terms, this usually relates to someone ensuring financial papers are up to date and sorted so that the executors will be able to readily manage the estate: but I was not entirely sure what this metaphor was intended to imply in the case of a cell.
Animistic language
Even a simple statement such as "First the neutrophil flattens itself"(p.28) whilst not implying a conscious process makes the neutrophil the active agent rather than a complex entity subject to internal mechanisms beyond its deliberate control. 3
So, why write
"Finally, the cell contracts itself tightly before exploding like a party popper that releases deadly NETs [neutrophil extracellular traps] instead of streamers."
Carver, 2017, p.27
rather than just "…the cell contracts tightly…"? I suspect because this offers a strong narrative (one of active moral agents engaged in an existential face-off) that is more compelling for readers.
Neutrophils are said to 'gush' and to 'race', but sometimes to be slowed down to a 'roll' when they can be brought to a stop ("stopping them in their tracks" if rolling beings have tracks?). But on other occasions they 'crawl'. Surely crawling is a rather specific means of locomotion normally associated with particular anatomy. Typically, babies crawl (but so might soldiers when under fire in a combat zone?)
There are many other examples of phrases that can be read as anthropomorphic, or at least animistic, and the overall effect is surely insidious on the naive reader. I do not mean 'naive' here to be condescending: I refer to any reader who is not so informed about the subject matter sufficiently to already understand disease and immunity as natural processes, that occur purely through physical and chemical causes and effects, and that have through evolution become part of the patterns of activity in organisms embedded in their ecological surroundings. A process such as infection or an immune response may look clever, and strategic, and carefully planned, but even when very complex, is automatic and takes place without any forethought, intentions, emotional charge or conscious awareness on the part of the microbes and body cells involved.
There are plenty of other examples in 'Immune' of phrasing that I think can easily be read as referring to agents that have some awareness of their roles/aims/preferences, and act accordingly. And by 'can easily be read', I suspect for many lay readers (i.e., the target readership) this means this will be their 'natural' (default) way of interpreting the text.
So (see Box 3 , below), microbes, cells, molecules and parasites variously are in relationships, boast, can beckon and be beckoned, can be crafty, can be egalitarian, can be guilty, can be ready to do things, can be spurred on, can be told things, can be treacherous, can be unaware (which implies, sometimes they are aware), can dance choreographed, can deserve blame, can find things appealing, can have plans, can mind their own business, can pay attention, can spot things, can take an interest, can wheedle (persuade), congregate, craft things, dare to do things, do things unwittingly, find things, get encouraged, go on quests, gush, have aims, have friends, have goals, have jobs, have roles, have skills, have strategies, have talents, have techniques, insinuate themselves, know things, like things, look at things, look out for things, play, outwit, race, seek things, smuggle things, toy with us, and try to do things.
Microbes moving in
One specific recurring anthropomorphic feature of Carver's descriptions of the various pathogens and the harmless microbes which are found on and in us, is related to finding somewhere to live – to setting up a home. Again, this is clearly metaphorical, a microbe may end up being located somewhere in the body, but has no notion, or feeling, of being at home. Yet the schema of home – finding a home, setting up home, being at home, feeling at home – is both familiar and, likely, emotionally charged, and so supports a narrative that fits with our life-experiences.
A squatter among pathogen society? Images by Peter H (photograph) and Clker-Free-Vector-Images (superimposed virus) from Pixabay
Viruses and bacteria are compared in terms of their travel habits (in relation to which, "The human hookworm…[has] got quite an unpleasant commute to work…"),
"…viruses are the squatters of pathogen society. Unlike bacteria, which tend to carry their own internal baggage for all their disease-making needs, viruses pack light. They hold only the genes they need to gain illegal entry to our cells and then instruct our cells' machinery to achieve the virus's aims. The cell provides a very happy home for the virus, and also gives it cover from the immune system."
Carver, 2017, p.35
These pathogens apparently form a society (where there is a distinction between what is and what is not legal 5) and individually have needs and aims. A virus not only lives in a home, but can be happy there. Again, such language does have a sensible meaning (if we stop to reflect on just what the metaphors can sensibly mean), but it is a metaphorical meaning and so should not be taken literally.
"…the human microbiota is the collective name for the 100 trillion micro-organisms that have made us their real estate. From the tip of your tongue to the skin you sit on, they have set up home in every intimate nook and cranny of our body…The prime real estate for these microbes, the Manhattan or Mayfair equivalent inside you and me, is the large intestine or colon. If you had a Lonely Planet or Rough Guide to your gut, the colon would have an entry something like this: 'The colon is a must-see multi-cultural melting-pot, where up to one thousand species of bacteria mingle and dine together every second of every day. In this truly 24/7 subterranean city, Enterococcirub shoulders with Clostridia; Bacteroides luxuriate in their oxygen-depleted surroundings and Bifidobacteria banquet on a sumptuous all-you-can-eat poo buffet. It's the microbe's place to see, and be seen'. ….[antibiotic's] potential to kill off vast swathes of the normal gut flora. This creates an open-plan living space for a hardy bacterium called Clostridium difficile. This so-called superbug (also known as C. diff) is able to survive the initial antibiotic onslaught and then rapidly multiplies in its newly vacated palace."
Carver, 2017, p.76-78
This metaphor is reflected in a number of contexts in Immune. So, the account includes (see Box 4, below) break ins, camps, communities, homes, lounging, palaces, penthouses, playgrounds, preferred places to live, real estate, residents, shops, squatters, suburban cul-de-sacs, and tenants .
What is for dinner?
The extracts presented above also demonstrate another recurring notion, that microbes and body cells experience 'eating' much like we do ('tasty morsel', 'dine together', 'banquet…buffet'). There are many other such illusions in 'Immune'.
We could explain human eating preferences and habits in purely mechanistic terms of chemistry, physics and biology – but most of us would think this would miss an important level of analysis (as if what people can tell us about what they think and feel about their favourite foods and their eating habits is irrelevant to their food consumption) and would be very reductive. Yet, when considering a single cell, such as a Kupffer cell, surely a mechanistic account in terms of chemistry, physics and biology is not reductionist, but exhaustive. Anything more is (as Einstein suggested about the aether) superfluous.
One favoured dining location is the skin:
"The Demodexdine on sebum (the waxy secretion we make to help waterproof our skin), as well as occasionally munching on our skin cells and even some unlucky commensal bacteria like Propionibacterium acnes…like many of us, P. acnes is a lipophile, which is to say it adores consuming fat. The sebum on our skin is like a layer of buttery, greasy goodness that has P. acnessmacking its lips. However, when P. acnes turns up to dine it has some seriously bad table manners, which can include dribbling chemicals all over our faces…[non-human] animal sebum lacks the triglyceride fats that P. acnes [2 ital] loves to picnic on." p.82
Carver, 2017, pp.81-82
It is hopefully redundant, by this point, for me to point out that Propionibacterium acnes does not adore anything – neither preferred foodstuffs nor picnics – but has simply evolved to have a nutritional 'regime' that matches its habitat. Whilst this extract immediately offers a multi-course menu of metaphors, it is supplemented by a series of other semantic snacks. So 'Immune' also includes references to buffet carts, chocolate chips, cookies, devouring, easy meals, gobbling up, making food appetising, making food tastier, munching, a penchant for parma ham and rare steak, soft-boiled eggs, tasty treats and yummy desserts.
Can you have too much of a metaphorical good thing?
I am glad I bought 'Immune'. I enjoyed reading it, and learnt from it. But perhaps a more pertinent question is whether I would recommend it to a non-scientist* interested in learning something about immunity and the immune system. Probably, yes, but with reservations.
Is this because I am some kind of scientific purist (as well as a self-acknowledged pedant)? I would argue not: if only because I am well aware that my own understanding of many scientific topics is shallow and rests upon over-simplifications, and in some cases depends upon descriptive accounts of what strictly need to be appreciated in formal mathematical terms. I do not occupy sufficiently high ground to mock the novice learner's need for images and figures of speech to make sense of unfamiliar scientific ideas. As a teacher (and author) I draw on figurative language to help make the unfamiliar become familiar and the abstract seem concrete. But, as I pointed out above, figurative language can sometimes help reveal (to help make the unfamiliar, familiar); but can also sometimes obscure, a scientific account.
I have here before made a distinction between the general public making sense of science communication in subjective and objective terms. Objective understanding might be considered acquiring a creditable account (that would get good marks in an examination, for example). But perhaps that is an unfair test of a popular science book: perhaps a subjective making-sense, where the reader's curiosity is satisfied – because 'yes, I see, that makes sense to me' – is more pertinent. Carver has not written 'Immune' as a text book, and if readers come away thinking they have a much better grasp of the immune system (and I suspect most 'naive' readers certainly would think that) then it is a successful popular science book.
My reservation here is that we know many learners find it difficult to appreciate that cornerstone of modern biology, natural selection (e.g., Taber, 2017), and instead understand the living world in much more teleological terms – that biological processes meet ends – occur to achieve aims – and do so through structures which have been designed with certain functions in mind.
So, microbes, parasites, cells, and antibodies, which are described as though they are sentient and deliberate actors – indeed moral agents seeking strategic goals, and often being influenced by their personal aesthetic tastes – may help immunity seem to make sense, but perhaps by reinforcing misunderstandings of key foundational principles of biology.
In this, Catherine Carver is just one representative of a widespread tendency to describe the living world in such figurative terms. Indeed, I might suggest that Carver's framing of the immune system as a defence force facing hostile invaders makes 'Immune' a main-stream, conventional, text in that it reflects language widely used in public science discourse, and sometimes even found in technical articles in the primary literature.
A myth is a story that has broad cultural currency and offers meaning to a social group, usually involving supernatural entities (demons, superhuman heroes, figures with powerful magic – perhaps microbial aesthetes and sentient cells?), but which is not literally true. e.g., Your immune system comprises a vast army of brave and selfless soldiers seeking to protect you from intruders looking to do you harm: an immune response is a microcosm of the universal fight between good and evil?
My question, then, is not whether Carver was ill-advised to write 'Immune' in the way she has, but whether it is time to more generally reconsider the widespread use of the mythical 'war' analogy in talking about immunity and disease.
Notes
1 Even if, for example, some interactions between groups of ants from different nests {e.g., see 'Ant colony raids a rival nest | Natural World – Empire of the Desert Ants – BBC'} look just as violent as anything from human history, their 'battles' are surely not planned as part of some deliberate ongoing campaign of hostilities.
2 The bacteria infecting us, if they could conceptualise the situation (which they cannot), would have no more reason to consider themselves a disease, than humans who 'infected' an orchard and consumed all the fruit would consider themselves a disease. Microbes are not evil for damaging us, they are just being microbes.
3 If my rock analogy seems silly, it is because we immediately realise that rocks are just not the kind of entities that behave deliberately in the world. The same is true of microbes and body cells -they are just not the kind of entities that behave deliberately in the world, and as long as this is recognised such metaphorical language is harmless. But I am not sure that is so immediately obvious to readers in these cases.
4 Such an issue can arise with descriptions about people as well. If I want to share a joke with a friend I may wink. If a fly comes close to my eye I may blink. Potentially these two actions may seem indistinguishable to an observer. However, the first is a voluntary action, but in the second case the 'I' that blinks is not me the conscious entity that ascribes itself self-hood, but an autonomous and involuntary subsystem! In a sense a person winks, but has blinking done to her.
5 If entry to our cells was 'illegal' in the sense of being contrary to natural laws/laws of nature, it would not occur.
* A note on being a scientist. Any research scientists reading this might scoff at my characterisation of the readers of popular science books as being non-scientists with the implied suggestion that I, by comparison, should count as a scientist. I have never undertaken research in the natural sciences, and, although I have published in research journals, my work in science education would be considered as social science – which in the Anglophile world does not usually count as being considered 'science' per se. However, in the UK, the Science Council recognises science educators as professional scientists. Learned societies such as the Royal Society of Chemistry and the Institute of Physics will admit teachers of these subjects as professional members, and even Fellows once their contributions are considered sufficient. This potentially allows registration as a Chartered Scientist. Of course, the science teacher does not engage in the frontiers of a scientific research field in the way a research scientist does, however the science teacher requires not only a much broader knowledge of science, but also a specialist professional expertise that enables the teacher to interrogate and process scientific knowledge into a form suitable for teaching. This acknowledges the highly specialised nature of teaching as an expert professional activity which goes far beyond the notion of teaching as a craft that can be readily picked up (as sometimes suggested by politicians).
Work cited
Bunge, M. (2017/1998). Philosophy of Science. Volume 1: From problem to theory. Routledge. (1967)
Carver, C. (2017). Immune. How your body defends and protects you. Bloomsbury Sigma.
"neutrophil is a key soldier" "the human body is like an exceedingly well-fortified castle, defended by billions of soldiers" "…the incredible arsenal that lives within us…" "the hidden army" "…our adaptive assassins, our T and B cells" "The innate system is the first line of defence…" skin: "…an exquisite barrier that keeps unwanted invaders out." "…your airways are exceedingly well booby-trapped passages lined with goblet cells, which secrete a fine later of mucus to trap dirt and bacteria." "Initially it was seen as a simple soldier with a basic skills set …Now we know it is a crafty assassin with a murderous array of killing techniques." "…ninja skill of neutrophils…", "ninja neutrophils" "macrophages are stationed at strategic sites…what an important outpost the liver is for the immune system" "NK cells [have] killer ways" "trigger-happy NK cells" "Ever neat assassins, NK cells" "vicious immune cells" compared to "a pack of really hungry Rottweilers" interleukins are "pro-inflammatory little fire-starters" "neutrophils, macrophages and other immune system soldiers" "T cells…activate their invader-destroying skills." "…a weapon with a name worthy of a Bond villain's invention: the Membrane Attack Complex" "miniature mercenaries" "a system whose raise d'etre is to destroy foreign invaders" "everything we do exposes us to millions of potential invaders." "…all invaders need an entry point…" "these tiny sneaks [e.g., E. coli]" "the dark-arts of pus-producing bacteria…" Neisseria meningitidis: "this particular invader" "foreign invaders" "an aggressive border patrol" 'Tregs are the prefects of the immune system…" "…the parasite larva has more in common with a time bomb…" "T cells…are the grand high inquisitors of the immune system, spotting and destroying infected cells and even cancer…these assassins" "imagining you have to make a Mr Potato Head army, and you know that the more variety in your vegetable warriors the better" "this process is about …making a mutant army." "they form a fighting force that rivals Marvel Comic's Fantasic Four" "each antibody molecule released as a single soldier" "The pancreas … acts as the commander-in-chief when its comes to controlling blood sugar levels." "our tiny but deadly defenders" "cells in the spleen with a specialised killer-skill" "wears a mask that conceals its killer features from its would-be assassins" "the microbiological mass murderers…the serial killers" "PA [protective antigen] is the muscled henchman" "the murderous cast of immune cells and messengers…this awe-inspiring army" "a microscopic army, capable of seeking out and destroying bacteria" "the terminators are targeted killers" "weaponised E. coli
Box 1: References to the immune system and its components as a defence force
"a kamikaze blaze of microbe-massacringglory" "an eternal war between our bodies and the legions of bacteria, viruses, fungi and parasites that surround us" "these invaders' attempts are thwarted" "battles" "all my innate defences would essentially hold the fort and in many instances this first line would be enough to wipe out the invader before the adaptive system gets a chance to craft bespoke weaponry." "the tears we shed [are] a form of chemical warfare." "…allowing the neutrophils to migrate through the blood vessel and into the battlefield of the tissue beyond" "the cell contracts itself tightly before exploding" "their friendly fire contributed to the death of the victim." "spewing microbe-dissolving chemicals into the surround tissue. This allows the neutrophil to damage many microbes at once, a bit like fishing by throwing dynamite into the water." "NK [natural killer] cells target the microbes that have made it inside our cells." "NK cells attack" "…the initial hole-poking assault…" "all part of the NK cell's plan to kill the cell." "…they trip the cell's self-destruct switch" "expose a cell to a severe, but not quite lethal threat…transform the cell into a hardened survivor" immune cells have an "ability to go on the rampage" "call up … immune system soldiers to mount a response" "leukaemia … has decimated a type of white blood cells called T cells" "it behaves like a Trojan horse [as in the siege of the City of Troy]" "telling our soldier cells to kick back and take some R & R" "the smoke signals of infection" "…like a showing of tiny hand grenades on the surrounding cells." "the donor cells would be vastly outnumbered and it would be like a band of rebels taking on a vast army on its home turf" "the recipient's own immune system is in a weakened state and unable to fight back" "…the antibodies …are therefore able to give a hostile welcome to alpha-gal-wearing malaria parasites." "…our gut bacteria effectively provide a training ground for the immune system – a boot camp led by billions of bacteria which teaches us to develop an arsenal of antibodies to tackle common foreign invader fingerprints…" "fighting on certain fronts" "edgy alliance" "shore up the intestinal defences by reinforcing the tight junctions which link the gut cells together" "our gut's security fence" "a self-cell that should be defended, not attacked" "this mouse-shaped Trojan horse" "the scanning eyes of the immune system" "a form of border control, policing" "…the bacteria-bashing brilliance…" "…the IgA effectively blocks and disables the invaders' docking stations…" "B cells and their multi-class antibody armoury have the ability to launch a tailored assassination campaign against almost anything" "the exquisitely tailored assassination of bacteria, viruses and anything else that dares enter the body" "One of the seminal victories in our war on bugs" "Some bacteria have a sugar-based cloaking device" "…tripped by the pollen attaching to the IgE-primed mast cells and, like pulling a pin on a grenade, causing them to unleash their allergy-inducing chemicals." "The almost instant assault of the immediate phase reaction occurs within minutes as the dirty bomb-like explosion of the mast cell fill the local area with a variety of rapidly acting chemicals." "..the battle against infectious diseases." "teaching the patrolling forces of the immune system to stand down if the cell they're interrogating is a healthy cell that belong to the body. It's a bit like a border patrol force wandering through the body and checking passports" "like a training camp for the newly created border guards". "ordering those that react incorrectly to self-destruct" "These bacteria have a sugar-based polysaccharide outer shell, which acts like a cloaking device" "the [oncolytic] viruses have a Swiss army knifeselection of killer techniques" "This approach slaughters these foot soldiers of our immune system…" "they [macrophages] have picked up a time bomb" "antibodies that act like heat-seeking missiles" "Kadcyla …has a double-pronged attack." "we are setting up easy antibiotic assault courses all over the place" "His suicidal minions were engineered to seek out a pneumonia-causing bacterium by the name of Pseudomonas aeruginosa and explode in its presence releasing a toxic cloud of a Pseudomonas-slaughtering chemical called pyocin." "it could secrete its killer payload" "stimulate the little terminators to produce and release their chemical warfare."
Box 2: References to disease and immune processes as war and violent activity
"The macrophage's … job as a first responder…" " osteoclasts and osteoblasts" are "Carver refers to "the bony equivalent of yin and yang…osteoblasts are the builders in this relationship" (said to be "toiling") …osteoclast, whose role is the constant gardener of our bones" "…a white blood cell called the regulatory T cell, or 'Treg' to its friends…" "…this biological barcode lets the T cell know that it's looking at a self-cell …" "…the ball of cells that makes up the new embryo finishes bumbling along the fallopian tube and finds a spot in the uterus to burrow into…" "By using this mouse-shaped Trojan horse the parasite gets itself delivered directly into the cat's gut, which is where Toxoplasma likes to get it on for the sexual reproduction stage of its lifecycle." "It's as if the trypanosome has a bag of hats that it can whip out and use to play dressing-up to outwit the immune system." "proteins… help smuggle the ApoL1 into the parasite" "Some parasites have a partner in crime…" "the chosen strategy of the roundworm Wuchereria bancrofti…uses a bacterium to help cloak itself from the immune system." "the work of a master of disguise…precisely what Wuchereria bancrofti is." "…its bacterial side-kick" "parasites that act as puppet masters for our white blood cells and direct our immune response down a losing strategy" "parasites with sartorial skills that craft themselves a human suit made from scavenged proteins" "parasites toy with us" "B cells have one last technique" "Chemical messengers beckon these B cells" "what AID [activation induced deaminase] seeks to mess with" "Each class [of antibody] has its own modus operandi for attacking microbes" "in terms of skills, IgG can activate the complement cascade" "…one of its [IgA] key killer skills is to block any wannabe invaders from making their way inside us." "the helper T cell and the cytotoxic T cell, which take different approaches to achieve the same aim: the exquisitely tailored assassination of bacteria, viruses and anything else that dares enter the body." "B cells, cytoxic T cells and macrophages in their quest to kill invaders" "T cells interact with their quarry" "add a frisson of encouragement to the T cell, spurring it on to activation." "the brutally egalitarian smallpox" "Polio is another virus that knows all about image problems." "the guilty allergen" "IgE and mast cells are to blame for this severe reaction [anaphylaxis]" "…The T regulatory cells identify and suppress immune cells with an unhealthy interest in normal cells." "the skills of a type of virus well versed in the dark arts of integrating into human DNA" "The spleen is a multi-talented organ" "to get rid of the crafty, cloaked bacteria" "Even once cells are able to grow despite the chemical melting pot they're stewing in telling them to cease and desist…" "It is believed that tumour cells bobbing about in the bloodstream try to evade the immune system by coating themselves in platelets…" "the cancer's ability to adorn itself" "They [oncolytic viruses] work by …drawing the attention of the immune system" "when the replicating virus is finally ready to pop its little incubator open" "…anthrax, which lurks in the alveoli awaiting its cellular carriage: our macrophages…" "The macrophages are doing what they ought … Completely unaware that they have picked up a time bomb…" "the microbial thwarting talents of interferons" "…your mAbs will do the legwork for you, incessantly scouring the body for their target destination like tiny, demented postal workers without a good union." "One of the tumour techniques is to give any enquiring T cells a 'these aren't the cells you're looking for' handshake that sends them on their way in a deactivated state, unaware they have let the cancer cells off the hook. Checkpoint inhibitor mAbs bind to the T cell and prevent the deactivating handshake from happening. This leaves the T cell alert and able to recognise and destroy the cancer cells." "A third neutrophil strategy…" "all part of the NK cell's plan to kill the cell." "…a majestic dance of immune cells and messengers, carefully choreographed…" "So my immune system's bag of tricks might not currently include a smallpox solution, but if I were to contract the disease my adaptive immune response would try its hardest to create one to kill the virus before it killed me." "Thus earwax can catch, kill and kick out the multitude of microbes that wheedle their way into out ears…" "Up to 200 million neutrophils gush out of our bone marrow and into the blood stream every day. They race around the blood on the look-out for evidence of infection." "a process called 'opsonisation' make consuming the bacterial more appealing to neutrophils" "the same siren call of inflammation and infection that beckoned the neutrophils." "…a set of varied and diverse circumstances can prompt multiple macrophages to congregate together and, like a massive Transformer, self-assemble into one magnificent giant cell boasting multiple nuclei." "The cell responds to the initial hole-poking assault by trying to repair itself…At the same time that it pulls in the perforin holes, the cell unwittingly pulls in a family of protein-eating granzymes…" "the gigantosome is more than just a pinched-off hole-riddled piece of membrane; its creation was all part of the NK cell's plan to kill the cell." caspases in cells "play an epic game of tag" Arachidonic acid: "Normally it just minds its own business" "The interferon molecule insinuates itself into the local area" "The chemokines …their ability to beckon a colourful array of cells to a particular location…they can call up neutrophils, macrophages and other immune system soldiers to mount a response to injury and infection…" "chemicals that can tell these cells where to go and what to do. These crafty chemicals…" "…the triad of goals of the complement system…" "It's the T cell's job to spot infected or abnormal cells." "Microbes aren't easy bedfellows" "…the 'lean' microbes won out over the 'obese' ones." "IgD is the most enigmatic of all the immunoglobins" "the parasite larva …treacherous"
Box 3: Examples of phrasing which might suggest that microbes, cells, etc., are sentient actors with human motivations
"Bifidobacterium infantis, a normal resident of the healthy infant gut" "trillions of microbes that make us their home" "…a much more diverse community of inner residents…" "Entamoeba … just happened to prefer to live in a multicultural colon." "…the mouth had the least stable community, like the microbial equivalent of transient squatters, while the vagina was the quiet suburban cul-de-sac of the map, with a fairly fixed mix of residents." "that's where they [Mycobacteria] set up home" "Neisseria meningitidis "sets up shop inside our cells…it breaks in…" "…Heliocobacter pylori (a.k.a H. pylori), a bacterium that makes its home in the sticky mucus that lines the stomach. While the mucus gives H. pylori some protection from the gastric acid, it also employed a bit of clever chemistry to make its home a touch more comfortable." Dracunculus medinensis will "seek out a mate, turning the abdominal wall into their sexual playground." "…plenty of creepy crawlies have been known to to call the human brain home, lounging among our delicate little grey cells…" the tapeworm Spirometra erinaceieuropaei : "…this particular tenant ensconced in their grey matter." "the worm…wriggled up through his body to reach its cranial penthouse where it could enjoy the luxury of a very special hiding spot." "There are flatworms, roundworms hookworms, whipworms, fleas and ticks, lice and amoeba. They're all queuing up to get a room at the palace of parasites" Clostridium tetani "can often set up camp in soil", "About 75 million people worldwide are thought to carry the dwarf tapeworm in their small intestine, where it lives a fairly innocuous life and causes its host few if any symptoms." "Though it may not seem like it, our nostrils are prime real estate and rival bacteria fight each other for resources, a fight which includes chemical warfare." "…we'll meet the creepy critters that like to call us home and the ways our immune system tries to show them the door."
Box 4: Microbes and cells described as the kind of entities which look for and set up homes.
"an all-you-can-eat oligosaccharide buffet for B. infantis [Bifidobacterium infantis]" "…complement's ability to make these bacteria seem tastier to our macrophages…" "Mycobacteria… actually want to be gobbled up by our macrophages…" "sprinkling C3b on the surface of bacteria makes them much more appetising to microbe-munching cells" macrophages 'devour' the remains of dead cells "…Salmonella, which likes a soft-boiled egg, and Toxoplasma gondii, which shares my penchant for parma ham and rare steak." Dracunculus medinensis "looks like an easy meal for a peckish water flea. Sadly for the water flea the parasite larva has more in common with a time bomb than a tasty snack ever should, and the treacherous morsel spends the next 14 days inside the flea…" "…flagging a microbe as munchable for macrophages…" "IgG …can mark targets as munchable. Thus any bacterium, virus or parasite coated in IgG finds itself the yummiest dessert on the buffet cart and every hungry macrophage rushes to get itself a tasty treat." "…from our brain to our bones, we are riddled with munching macrophages…" opsonisation: "much like sprinkling tiny chocolate chips on a bacterial cookie" "Demodex dine on sebum…as well as occasionally munching on our skin cells" "P. acnes is a lipophile, which is to say it adores consuming fat. The sebum on our skin is like a layer of buttery, greasy goodness that has P. acnes smacking its lips." "when "P. acnes turns up to dine it has some seriously bad table manners" " P. acnes loves to picnic."
Box 5: References to the culinary preferences and habits of entities such as microbes and immune cells
