A faecal transplant is like wild flower seeds in some soil
Keith S. Taber
"Many animals naturally ate each other's poo…as a way of staying healthy" Prof. Tim Spector. (Original image by Debbie De Jager from Pixabay, with apologies to Monty Python)
I was listening to a podcast from 'Science Stories' (BBC Radio 4) about 'Lady Mary Montagu's Smallpox Experiment', where Naomi Alderman described how the aforementioned Lady Mary Wortley Montagu brought the practice of opening veins to introduce some smallpox into the body, as a way of protecting against the deadly disease, back from Turkey to Britain.
This was compared with the process of faecal transplantation which was apparently first used in China, and is increasingly being seen as a valuable treatment for some gut disorders. This is the process of ingesting, under carefully controlled conditions, some human faeces – either some of your own carefully preserved (for example, some cancer patients have a sample collected and stored before starting chemotherapy), or from some donor who is willing to offer some of their own. Unlike some other donor procedures (such as kidney donation) this is non-invasive and concerns material most of us just dispose of anyway!
Tim Spector, Professor of Genetic Epidemiology at Kings College, London explained the significance of the gut microbiome, the community of something like 100 trillion microbes that typically occupy a human gut. The importance of these organisms for human health is increasingly being appreciated.
Treating Clostridium difficile infection
Disturbances of the gut microbiome can lead to ill health. One particular example is the condition known as Clostridium difficile infection ('C. diff') – which is commonly experienced in hospitals when patients have extensive courses of antiobiotics – which can sadly kill the useful gut microbes as well those disease-causing organisms being targeted. Clostridium difficile (being itself unaffected by many commonly used antibiotics) can in these circumstances reproduce rapidly and vastly increase its numbers. This is problematic as the organism releases a toxin.
C. diff infection can lead to the sufferer needing to visit the toilet urgently and repeatedly – many times each day. This is not only undesirable in itself, but interferes with getting nutrition from food (if the person has any appetite to eat), and leads to dangerous dehydration – and can have other complications. So, this is a very serious condition, and it is readily transmitted from one person to another.
"C. difficile is an infectious Gram-positive spore-forming bacillus microorganism of the gastrointestinal tract, and its toxin expression causes gastrointestinal illness with a wide spectrum of severity, ranging from mild diarrhea to pseudomembranous colitis, toxic megacolon, sepsis-like picture and death…"
Bien, Palagan & Bozko, 2013: 53
Many people have a low level of Clostridium difficile specimens in their gut normally, but as one small part of the much larger and diverse population of gut microbes – in which context they cause no problems.
"C. difficile does not cause any significant disease when it is present in small numbers. However, disturbance of the normal intestinal flora (dysbiosis) by several potential causative factors may result in unlimited [sic] expansion of C. difficile in the microbiota, leading to inflammation and damage of the gut mucosa…"
Bien, Palagan & Bozko, 2013: 56
Someone who has suffered from C. diff infection needs a way to repopulate their gut with a good range of the usual different microbes. And that is when consuming a sample of a healthy person's excrement can be useful. (This is of course done under medical direction and supervision, both to maintain hygiene and to ensure the donor does not have medical conditions that might be passed on with the sample.)
A teaching analogy for faecal transplantation
This was all explained by Prof. Spector using an analogy.
Analogies are comparisons where a less familiar, and perhaps abstract or counterintuitive, concept is explained in terms of something familiar that can be seen to have a similar conceptual structure (see the figure). Analogies are commonly used in science teaching and public communication of science (as here in a radio programme) to introduce scientific ideas.
Prof. Spector developed a comparison between the different microbes found in the gut, and the plants growing in a garden:
"These nasty infections are the most extreme, if you like, that pretty much wipe out most of our normal species. So … we might, say, start with a thousand species and people [with C. diff] might be down to just ten or so, different ones and so nasty ones take over. It's a bit like a garden that has gone very badly wrong and you have put too much herbicide all over it and it looks like an Arizona back yard with a few burning tyres in it. It's very easy for things to take over that and what we want to get, is by putting these bugs in there, to create a really healthy garden that gets back to normal that looks like a nice English country garden with lots of blooms, and really good soil, and lots of plants interacting with each other, and that's the way to think about these microbes, but to do that, to get to this nice rosy picture of a country garden you have to go through yucky stages first"
Before and after faecal transplantation: a medical treatment that can transform your 'garden'? (Images by Simon (left) and Prawny (right) from Pixabay) [Move the slider to change between the pictures].
So the idea of taking a sample of someone else's excrement into our own gut may seem "yukky" – and is definitely NOT recommended without proper procedures and supervision – but may sometimes be a sensible and beneficial medical treatment. Just think of it as resewing the garden of the gut with a nice selection of seeds that will give rise to a diverse selection of colourful blooms.
Naomi Alderman: Instead of poo, we could think to ourselves, 'wild flower seeds'
Tim Spector: It's wild flower seeds with a bit of soil in it as well, so they have come in their own pot [sic] if you like.
'wild flower seeds with a bit of soil…in their own pot'? (Images by OpenClipart-Vectors from Pixabay)
Work cited:
Bien, J., Palagani, V., & Bozko, P. (2013). The intestinal microbiota dysbiosis and Clostridium difficile infection: is there a relationship with inflammatory bowel disease? Therapeutic advances in gastroenterology, 6(1), 53-68. doi:10.1177/1756283X12454590 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3539291/
As part of the primary scientific literature, it publishes articles written by specialist scientists in a technical language intended to be understood by other specialists. Dense scientific terminology is not used to deliberately exclude general readers (as sometimes suggested), but is necessary for scientists to make a convincing case for new knowledge claims that seem persuasive to other specialists. This requires being precise, using unambiguous technical language."The thingamajig kind of, er, attaches to the erm, floppy bit, sort of" would not do the job.
Science News however is news media – it publishes journalism (indeed, 'since 1921' the site reports – although that's the publication and not its website of course.) While science journalism is not essential to the internal processes of science (which rely on researchers engaging with each other's work though scholarly critique and dialogue) it is very important for the public's engagement with science, and for the accountability of researchers to the wider community.
Science journalists have a job similar to science teachers – to communicate abstract ideas in a way that makes sense to their audience. So, they need to interpret research and explain it in ways that non-specialists can understand.
The news article told me
"Like a shaggy dog in springtime, some black holes have to shed… Unlike dogs with their varied fur coats, isolated black holes are mostly identical. They are characterized by only their mass, spin and electric charge. According to a rule known as the no-hair theorem, any other distinguishing characteristics, or "hair," are quickly cast off. That includes magnetic fields."
Conover, 2013
Here there is clearly the use of an analogy – as a black hole is not the kind of thing that has actual hair. This would seem to be an example of a journalist creating an analogy (just as a science teacher would) to help 'make the unfamiliar familiar' to her readers:
just as
dogs with lots of hair need to shed some ready for the warmer weather (a reference to a familiar everyday situation)
so, too, do
black holes (no so familiar to most people) need to lose their hair…
Surely a better analogy would be along the lines that just as dogs with lots of hair need to shed some ready for the warmer weather, so to do black holes need to lose their magnetic fields…
An analogy is used to show a novel conceptual structure (here, relating to magnetic fields around black holes) maps onto a more familiar, or more readily appreciated, one (here, that a shaggy dog will shed some of its fur). A teaching analogy may not reflect a deep parallel between two systems, as its function may be just to introduce an abstract principle.
Conover did not invent the 'hair' reference for her ScienceNews piece – rather she built her analogy on a term used by the scientists themselves. Indeed, the title of the cited research journal article was "Magnetic Hair and Reconnection in Black Hole Magnetospheres", and it was a study exploring the consequences of the "no-hair theorem" – as the authors explained in their abstract:
"The no-hair theorem of general relativity states that isolated black holes are characterized [completely described] by three parameters: mass, spin, and charge."
Bransgrove, Ripperda & Philippov, 2021
However, some black holes "are born with magnetic fields" or may "acquire magnetic flux later in life", in which case the fields will vary between black holes (giving an additional parameter for distinguishing them). The theory suggests that these black holes should somehow lose any such field: that is, "The fate of the magnetic flux (hair) on the event horizon should be in accordance with the no-hair theorem of general relativity" (Bransgrove, Ripperda & Philippov, 2021: 1). There would have to be a mechanism by which this occurs (as energy will be conserved, even when dealing with black holes).
So, the study was designed to explore whether such black holes would indeed lose their 'hair'. Despite the use of this accessible comparison (magnetic flux as 'hair'), the text of the paper is pretty heavy going for someone not familiar with that area of science:
"stationary, asymptotically flat BH spacetimes…multipole component l of a magnetic field…self-regulated plasma…electron-positron discharges…nonzero stress-energy tensor…instability…plasmoids…reconnection layer…relativistic velocities…highly magnetized collisionless plasma…Lundquist number regime…Kerr-schild coordinates…dimensionless BH spin…ergosphere volume…spatial hypersurfaces…[…and so it continues]"
(Bransgrove, Ripperda & Philippov, 2021: 1).
"Come on Harry, you know full well that 'the characteristic minimum plasma density required to support the rotating magnetosphere is the Goldreich-Julian number density' [Bransgrove, Ripperda & Philippov, 2021: 2], so hand me that hyperspanner." Image from Star Trek: Voyager (Paramount Pictures)
Spoiler alert
I do not think I will spoil anything by revealing that Bransgrove and colleague conclude from their work that "the no-hair theorem holds": that there is a 'balding process' – the magnetic field decays ("all components of the stress-energy tensor decay exponentially in time"). If any one reading this is wondering how they did this work, given that most laboratory stores do not keep black holes in stock to issue to researchers on request, it is worth noting the study was based on a computer simulation.
That may seem to be rather underwhelming as the researchers are just reporting what happens in a computer model, but a lot of cutting-edge science is done that way. Moreover, their simulations produced predictions of how the collapsing magnetic fields of real black holes might actually be detected in terms of the kinds of radiation that should be produced.
As the news item explained matters:
Magnetic reconnection in balding black holes could spew X-rays that astronomers could detect. So scientists may one day glimpse a black hole losing its hair.
Conover, 2013
So, we have hairy black holes that go through a balding process when they lose their hair – which can be tested in principle because they will be spewing radiation.
Balding is to hair, as…
Here we have an example of an analogy for a scientific concept. Analogies compare one phenomenon or concept to another which is considered to have some structural similarity (as in the figure above). When used in teaching and science communication such analogies offer one way to make the unfamiliar familiar, by showing how the unfamiliar system maps in some sense onto a more familiar one.
hair = magnetic field
balding = shedding the magnetic field
Black holes are expected to be, or at least to become, 'hairless' – so without having magnetic fields detectable from outside the event horizon (the 'surface' connecting points beyond which everything, even light, is unable to 'escape' the gravitational field and leave the black hole). If black holes are formed with, or acquire, such magnetic fields, then there is expected to be a 'balding' process. This study explored how this might work in certain types of (simulated) black holes – as magnetic field lines (that initially cross the event horizon) break apart and reconnect. (Note that in this description the magnetic field lines – imaginary lines invented by Michael Faraday as a mental tool to think about and visualise magnetic fields – are treated as though they are real objects!)
Some such comparisons are deliberately intended to help scientists explain their ideas to the public – but scientists also use such tactics to communicate to each other (sometimes in frivolous or humorous ways) and in these cases such expressions may do useful work as short-hand expressions.
So, in this context hair denotes anything that can be detected and measured from outside a black hole apart form its mass, spin, and charge (see, it is much easier to say 'hair')- such as magnetic flux density if there is a magnetic field emerging from the black hole.
A dead metaphor?
In the research paper, Bransgrove, Ripperda and Philippov do not use the 'hair' comparison as an analogy to explain ideas about black holes. Rather they take the already well-established no-hair theorem as given background to their study ("The original no-hair conjecture states that…"), and simply explain their work in relation to it ("The fate of the magnetic flux (hair) on the event horizon should be in accordance with the no-hair theorem of general relativity.")
Whereas an analogy uses an explicit comparison (this is like that because…), a comparison that is not explained is best seen as a metaphor. A metaphor has 'hidden meaning'. Unlike in an analogy, the meaning is only implied.
"The no-hair theorem of general relativity states that isolated black holes are characterized by three parameters: mass, spin, and charge";
"The original no-hair conjecture states that all stationary, asymptotically flat BH [black hole] spacetimes should be completely described by the mass, angular momentum, and electric charge"
Bransgrove and colleagues do not need to explain why they use the term 'hair' in their research report as in their community it has become an accepted expression where researchers already know what it is intended to mean. We might consider it a dead metaphor, an expression which was originally used to imply meaning through some kind of comparison, but which through habitual use has taken on literal meaning.
Science has lots of these dead metaphors – terms like electrical charge and electron spin have with repeated use over time earned their meanings without now needing recourse to their origins as metaphors. This can cause confusion as, for example, a learner may develop alternative conceptions about electron spin if they do not appreciate its origin as a metaphor, and assumes an electron spins in the same sense as as spinning top or the earth in space. Then there is an associative learning impediment as the learner assumes an electron is spinning on its axis because of the learner's (perfectly reasonable) associations for the word 'spin'.
The journalist or 'science writer' (such as Emily Conover), however, is writing for a non-specialist readership, so does need to explain the 'hair' reference. So, I would characterise the same use of the terms hair/no-hair and balding as comprising a science analogy in the news item, but a dead metaphor in the context of the research paper. The meaning of language, after all, is in the mind of the reader.
The unbelievable truth – do bacteria focus incident light onto their back-sides, so they can tell which way to go?
"Bacteria are just tiny eyeballs" sounds like another science analogy, but is actually something I learned today from BBC Radio 4.
On David Mitchell's "The Unbelievable Truth" panelists read essays on a topic, but populated with false (and preferably funny) statements. The premise is great: the panelists try to sneak in some true facts which sound so unlikely that they are confused with the falsehoods. Panelists get marks for correctly spotting truths in another panelist's little essay, or for completing their own talk with some of their 'unbelievable' truths not being spotted.
On today's episode I was shocked top learn from Dr Ria Lina that "…bacteria are just tiny eyeballs…".
Because they are not.
Well, not exactly…
Her essay was talking about germs, and included:
"Transmission of disease is determined by how many victims germs can actually see. Viruses have load of tiny little eyes so they are able to see loads and loads of potential victims in all different directions, whereas bacteria are just tiny little eyeballs, and fungi are extremely short sighted poor things, which is why they are only able to infect places like feet."
At the end of the round, David reported that the part about bacteria as eyes was true, although he did not seem very convinced:
David: You have managed to smuggle three truth past the rest of the panel, which are that bacteria are just tiny eyeballs – although to me that sounds a bit like things being put into language that people understand, because they are not like tiny eyeballs, really are they?
Ria: Well the light goes in and it reflects off the back surface which acts like a rudimentary retina…
Right,
…and also you have got to remember that the eye had evolved multiple times in multiple ways, so the squid eye and the human eye even though they both work the same way did not come from the same universal ancestor…
Oh right
…so, bacterial eye is basically what we are seeing now is the beginning of – [sadly interrupted by another panelist]. I'm such a geek…
Ria Lina – self-confessed geek (and there is nothing wrong with that)
I presumed there must be some basis for this claim; that Dr Lina (PhD in viral bioinformatics) must be drawing upon some actual science, but I was not sure what. Whereas the eyeball has a back surface there is no inherent back surface for a bacterium – so this must mean any inside surface.
Although light does reflect off the retina (red eye in camera images is due to the light reflecting from the retina with its rich supply of blood vessels) – the function of the retina is to absorb light and to then signal information forward based on the pattern of light detected. Some species have a reflecting layer (tapetum lucidum) behind the retina to increase efficiency – some light not absorbed by the retina initially gets a second pass though after reflection which allows increased absorption. But this is only useful because there are cells capable of absorbing the light and processing information based on the absorption.
The bacterium is a single cell, so the most sense I could make of this is that when light absorption is useful, a reflecting inner surface could be valuable. This might make sense for cyanobacteria to increase the efficiency of photosynthesis by reflecting light not absorbed on the first pass.
What did we do before the internet?
I did some quick searching on line.
Someone had developed a method of identifying bacterial colonies through light back-scattered, which was useful because the technique using transmitted light was impractical in species that absorb most of the incident light.
Interesting, but the light was not being reflected internally, if I understood the paper.
Someone has developed a technique to increase the light absorbed by photosynthetic algae and cyanobacteria that did use total internal reflection – but if I read correctly this reflection is in the light guide on the way to the cell, not inside it.
Image by Stephan Ernst from Pixabay
So, I was still not buying the eyeballs story. Then I found a report of how "Cyanobacteria use micro-optics to sense light direction",
"Here, we establish that individual Synechocystis cells can directly and accurately perceive the position of a unidirectional light source, and control their motility so as to move towards it. We then show that Synechocystis cells act as microlenses, and that the light intensity gradient across the cell due to this lensing effect is far greater than the effects of shading due to light absorption or reflection. Finally, we use highly-localized laser excitation to show that specific excitation of one side of the cell triggers movement away from the light, indicating that positive phototaxis results from movement away from an image of the light source focused on the opposite side of the cell. Essentially, the cell acts as a microscopic eyeball."
Schuergers et al.,2016
Wow, nature never ceases to amaze.
So, basically the cell itself focuses incident light to be concentrated at the 'back' of the cell (where back is the side opposite the light source), organelles that absorb light can in effect detect this light 'spot', and the bacterium has evolved to move 'forward' towards the light source based on where in the cell this higher light intensity occurs. The system in effect 'knows' which direction to take as forward.
"Here we have shown that Synechocystis cells act as very effective spherical microlenses that focus a sharp image of a light source at the opposite edge of the cell. This implies that positive phototaxis (i.e. movement towards a light source) is actually triggered as a negative response to the focused spot of light at rear periphery of the cell."
Schuergers et al.,2016
This does not seem to involve internal reflection, so perhaps there is another source for the eyeballs claim (possibly with an even more amazing nugget of science) that I have missed and which was the basis of Dr Lina's claim.
Bacteria are not just tiny eyeballs, but…
I still think it is not correct to claim that "bacteria [generally, or even this particular bacteria] are just tiny eyeballs". This is a simplification, and probably not an 'intellectually honest' one that could be considered to be at the 'optimum level of simplification' for communicating a key scientific idea stripped of distracting complications.
Indeed the real wonder of Synechocystis is that it a single cell that acts as an integrated, responsive, coherent system: energy collection unit, eyeball, lens, photo-receptors, controller/processor, and locomotive unit.
Despite this quibble, given the context of the claim (made as part of a comedy show, not a peer reviewed research conference) I think I am impressed enough to have to revise the 'Tweet' I was going to send Dr Lina calling her out for telling an unbelievable lie on national radio. I should have remembered that it is very difficult to come up with any claim about the living world which is so fantastic that one can be confident there is not an example of a species out there which affirms the claim. When it comes to nature we often need to believe the unbelievable truth.
Work cited:
Huisung Kim, Iyll-Joon Doh, Jennifer Sturgis, Arun K. Bhunia, J. Paul Robinson, Euiwon Bae (2016) Reflected scatterometry for noninvasive interrogation of bacterial colonies, Journal of Biomedical Optics. 21(10), 107004, doi: 10.1117/1.JBO.21.10.107004.
Ooms, M. D., Sieben, V. J., Pierobon, S. C., Jung, E. E., Kalontarov, M., Erickson, D., & Sinton, D. (2012). Evanescent photosynthesis: exciting cyanobacteria in a surface-confined light field. Physical Chemistry Chemical Physics, 14(14), 4817-4823. doi:10.1039/C2CP40271H
Schuergers, N., Lenn, T., Kampmann, R., Meissner, M. V., Esteves, T., Temerinac-Ott, M., . . . Wilde, A. (2016). Cyanobacteria use micro-optics to sense light direction. Elife, 5, e12620.
Unseen minerals all around us (Ockham's Razor – ABC)
I was listening to a recent episode of 'Ockhams' razor' (ABC's series of short science and technology essays) from 2020 called 'Unseen minerals all around us'. As a radio programme, the audience was likely to be diverse in terms of age, interests, and background knowledge and experiences.
The speaker was Allison Britt, Director of Mineral Resources Advice and Promotion, Geoscience Australia ("Australia's pre-eminent public sector geoscience organisation"), and she was describing the large number of elements used in constructing a modern mobile phone – apparently someone had put a phone in a laboratory blender and analysed the smoothie produced! (Please note: that is not a safe activity for a home science practical.)
Allison Britt, Director of Mineral Resources Advice & Promotion, Geoscience Australia – at a live recording of 'Okham's razor'. (Source: Twitter)
As a science teacher (well, retired – but once a science teacher, always a science teacher at heart at least) I tend to be primed to focus on the ways in which teachers and scientists 'make the unfamiliar familiar', and Britt used an analogy with multiple targets.
The source domain was something familiar from everyday life – seasoning food.
I thought this worked really well, although as a purist (and, as noted here before, something of a pedant) I would have liked the third of her comparisons to refer to a difference that was a matter of degree (e.g., 'taste better' cf. 'work more efficiently'). That said, Britt's formulation worked better as scientific poetry:
So, just like adding salt and pepper to a meal makes it taste better:
putting a little rhenium in a jet engine makes it burn faster and hotter;
putting a little scandium in an aeroplane makes it lighter and stronger;
and putting a little indium in your mobile phone makes the touchscreen work.
Britt, 2021
This was an example of a science communicator making the point of how adding a small, sometimes trace, quantity of a substance can make a substantive difference to properties. I imagine that virtually everyone listening to this would have effortlessly understood the comparison – a key criterion for an effective teaching analogy.
Dampening down COVID? (Image by Iván Tamás from Pixabay)
Analogy in science
Analogy is a common technique used in science and science education. In scientific work analogy may be used as a thinking tool useful for generating hypotheses to explore – "what if X is like Y, then that might mean…". That is, we think we understand system Y, so, if for a moment we imagine that system X may be similar, then by analogy that would mean (for example) that A may be the cause of B, or that if we increase C then we might expect D to decrease… Suggesting analogies has been used as a way of introducing a creative activity into school science (Taber, 2016).
Scientists also sometimes use analogies to explain their ideas and results to other scientists. However, analogies are especially useful in explaining abstract ideas to non-experts, so they are used in the public communication of science by comparing technical topics with more familiar, everyday ('lifeworld') phenomena. In the same way, teachers use analogies as one technique for 'making the unfamiliar familiar' by suggesting that the unfamiliar curriculum focus (the target concept to be taught) is in some ways just like a familiar lifeworld phenomena (the analogue or source concept).
So, I was interested to hear Prof. Andrew Hayward, Professor of Infectious Disease Epidemiology and Inclusion Health Research at UCL (University College London), being interviewed on the radio and suggesting that COVID was like a fire:
"Sometimes I like to think of, you know, COVID as a fire, if we are the fuel, social mixing is the oxygen that allows the fuel to burn, vaccines the water that stops the fuel from burning, and COVID cases are the sparks that spread the fire. So, we are doing well on vaccines, but there's lots of dried wood left."
There's quite a lot going on in that short statement. If Prof. Hayward had stopped at "sometimes I like to think of COVID as a fire" this would have been a simile where it is simply observed that one thing is conceived as being a bit like another.
Simile offers a comparison and leaves the listener or reader to work out the nature of the similarity (whereas metaphor, where one thing is described to be another, an example would be 'COVID is a fire', leaves the audience to even appreciate a comparison is being made). Analogy goes further, as it makes a comparison between two conceptual structures (two systems), such that by mapping across them we can understand how the structure of the unfamiliar is suggested to be like the more familiar structure.
That is, there is a mapping (see the figure below) that is based on pairings across the analogy. Here fire and COVID disease are each treated as systems with components that are structured in a parallel way:
COVID (illness): fire
people: fuel
social mixing: oxygen
vaccines: water
COVID cases: sparks
A graphic representation of Prof. Hayward's use of analogy
A lot of us are like kindling
Moreover, having set up this analogy, we are offered some additional information – we are doing well on vaccines (= there is plenty of water to stop fuel burning), but there is still a lot of dried wood. The listener has to understand that the dry wood refers to fuel, and this maps (in the analogy) onto lots of people who can still become infected.
I suspect most people (science teachers perhaps excepted) listening to this interview will not have even explicitly noticed the nature of the analogy, but rather automatically processed the comparison. They would have understood the message about COVID through the analogy, rather than having to actively analyse the analogy itself.
We can stop the sparks spreading the fire
Professor Hayward was asked about contact tracing and suggested that
"…the key thing is the human discussion with somebody who has COVID to identify who their contacts are and to ask them to isolate as well, and that really stops those sparks getting into the population and really helps to dampen down the fire."
That is, that potential COVID cases (that are like sparks in the fire system) can be prevented from mixing with the wider population (who are like fuel in the fire system) and this will dampen down the fire (the illness in the COVID system). {Note 'dampen down' seems to be a metaphor here rather than a true part of the analogy (in which it is the vaccines that have the effect of 'literally' {analogously} dampening down the fire). Stopping sparks mixing with fuel will limit new areas of combustion starting rather than dampening down the existing fire.}
An argument about contact tracing made using the analogy
Again, most people listening to this would likely have taken on board the intended meaning quite automatically, without having to deliberately analyse this answer – even though the response shifts between the target topics (the COVID disease system) and the analogue (the fire system) – so the sparks (fire system – equivalent to infectious cases) are stopped from getting into the population (COVID system – equivalent to the fuel supply).
This is reminiscent of chemistry teaching which slips back and forth between macroscopic and molecular levels of description – and so where references to, for example, hydrogen could mean the substance or the molecule – and the same word may have a different referent at different points in the same utterance (Taber, 2013). Whether this is problematic depends upon the past experiences of the listener – someone with extensive experience of a domain (probably most of the audience of a serious news magazine programme understand enough about combustion and infection to not have to deliberate on the analogy discussed here) can usually make these shifts automatically without getting confused.
Fire requires…AND…AND…
An analogy can only be effective when the analogue is indeed more familiar to the audience (you cannot make the unfamiliar familiar by comparing an unfamiliar target with an analogue that is also unfamiliar) so the use of the analogy by Professor Hayward assumed some basic knowledge about fire. Indeed it seemed to assume knowledge of the so-called 'fire triangle'.
Three factors are need to initiate/maintain combustion: fire may be stopped by removing one or more of these.
This is the idea that for a fire to commence or continue there need to be three things: something combustible to act as fuel; AND oxygen (or another suitable substance – as when iron filings burn in chlorine – but in usual circumstances it will be oxygen); AND a source of energy sufficient to initiate reaction (as burning is exothermic, once a fire is underway it may generate enough heat to maintain combustion – and sparks may spread the fire to nearby combustible material). To extinguish a fire, one needs to remove at least one of these factors – water can act as a heat sink to decrease the temperature, and may also reduce the contact between the fuel and oxygen. Preventing sparks from transferring hot material that can initiate further sites of combustion (providing energy to more fuel) can also be important.
Unobtrusive pedagogy
The quotes here were part of a short interview with a broadcast journalist and intended for a general public audience. Prof. Hayward introduced and developed his analogy as just sharing a way of thinking, and indeed analogy is such a common device in conversation that it was not obviously marked as a pedagogic technique. However, when we think about how such a device works, and what is expected of the audience to make sense of it, I think it is quite impressive how we can often 'decode' and understand such comparisons without any conscious effort. Providing, of course, that the analogue is indeed familiar, and the mapping across the two conceptual structures can be seen to fit.
Do species become more different from one another to avoid breeding?
Keith S. Taber
A tamarin monkeyA different tamarin
They say "opposites attract". True perhaps for magnetic poles and electrical charges, but the aphorism is usually applied to romantic couples. It seems like one of those sayings that survives due to the 'confirmation bias' in human cognition. That is, as long as from time to time seemingly unlikely couplings occur, the explanation that 'opposites attract' seems to have some merit, even in it only applies to a minority of cases.
Apparently, in the area of overlap the red-handed tamarins seemed to have adapted one of their calls so it sounds very similar to that of the pied tamarins. (N.b. The images above represent two contrasting species, just as an illustration.) The suggested explanation was that this modification made it more likely that the monkeys of different types would recognise each other's calls – in particular that "…they are trying to be understood, so they don't end up in a fight…".
Anthropomorphism?
I wondered if these monkeys were really "trying" to achieve this, or whether this might be an anthropomorphism. That is, were the red-handed tamarins deliberately changing their call in this way in order to ensure they could be understood – or was this actually natural selection in operation – where, because there was an advantage to cross-species communication (and there will be a spread of call characteristics in any population), over time calls that could be understood by monkeys of both species would be selected for in a shared niche.
Then again, primates are fairly intelligent creatures, so perhaps Dr Dunn (who, unlike me is an evolutionary biologist) means this literally, and this is something deliberate. Certainly, if the individual monkeys are shifting their calls over time in response to environmental cues, rather than the shift just occurring across generations, then that would seem to suggest this is learning rather than evolution. (Of course, it could be implicit learning based on feedback from the responses to their behavior, and still may not be the monkeys consciously adopting a strategy to be better understood.)
Becoming more distinct
Dr Dunn's explanation of the wider issue of how similar animals will compete for scarce resources intrigued me:
"When you have species that are closely related to one another and live in sort of overlapping areas there's quite a lot of pressure because they're likely to be competing for key resources. So, sometimes we see that these species actually diverge in their traits, they become more different from one another. Examples of that are sort of coloration and the way that animals look. Quite often they become more distinct than you would expect them to, to avoid breeding [sic] with one another."
My initial reaction to this was to wonder why the two species of monkeys needed to avoid breeding with each other. 'Breeding' normally refers to producing offspring, reproduction, but usually breeding is not possible across species (except sometimes to produce infertile hybrids).
Presumably, all tamarins descended from a common ancestor species. Speciation may have occurred when different populations become physically separated and so were no longer able to inter-breed (although still initially sexually compatible) simply because members of the two groups never encountered each other. Over time (i.e., many generations) the two populations might then diverge in various traits because of different selection pressures in the two different locations, or simply by chance effects* which would lead to the two gene pools drifting in different ways.
Two groups that had formed separate species such that members of the two different species are no longer able to mate to produce fertile offspring, might subsequently come to encounter each other again (e.g., members of one species migrating into to the territory of the other) but inter-breeding would no longer be possible. A further mechanism to avoid breeding (by further "diverge[nce] in their traits") would not seem to make any difference.
If they actually cannot breed, there is no need to avoid breeding.
A breeding euphemism?
However, perhaps 'breeding' was being used by Dr Dunn as a euphemism (this was after all a family-friendly radio programme broadcast in the afternoon), as a polite way of saying this might avoid the moneys copulating with genetically incompatible partners – tamarins of another species. As tamarins presumably do not themselves have a formal biological species concept, they will not avoid coupling with an animal from a different species on the grounds that they cannot breed and so it would be ineffective. They indulge in sexual activity in response to instinctive drives, rather than in response to deliberate family planning decisions. That is, we might safely assume these couplings are about sexual attraction rather than a desire to have children.
I think that was what Jürgen Habermas may have meant when he wrote that:
"…the reproduction of every individual organism seems to warrant the assumption of purposiveness without purposeful activity…"
In terms of fitness, an animal is clearly more likely to have offspring if it is attracted to a sexually comparable partner than a non-compatible one. Breeding is clearly important for the survival of the species, and uses precious resources. Matings that could not lead to pregnancy (or, perhaps worse from a resource perspective, might lead to infertile hybrids that need to be nurtured but then fail to produce 'grandchildren'), would reduce breeding success overall in the populations. Assuming that a tamarin is more likely to be attracted to a member of a different species when it does not look so different from its own kind, it is those monkeys in the two groups that look most alike who are likely to be inadvertently sharing intimate moments with biologically incompatible partners.
A teleological explanation
Dr Dunn's suggestion that "quite often [the two species] become more distinct than you would expect them to, to avoid breeding with one another" sounds like teleology. That is, it seems to imply that there is a purpose (to avoid inter-breeding) and the "species actually diverge in their traits" in order to bring about this goal. This would be a teleological explanation.
I suspect the actual explanation is not that the two species "come more distinct…to avoid breeding with one another" but rather than they come more distinct because they cannot breed with each other, and so there is a selection advantage favouring the most distinct members of the two different species (if they are indeed less likely than their less distinguishable conspecifics to couple with allospecific mates).
I also suspect that Dr Dunn does not actually subscribe to the teleological argument, but is using a common way of talking that biologists often adopt as a kind of abbreviated argument: biologists know that when they refer to evolution having a purpose (e.g., to avoid cross-breeding), that is only a figure of speech.
Comprehension versus accuracy?
However, I am not sure that is always so obvious to non-specialists listening to them. Learners often find natural selection a challenging topic, and many would be quite happy with accepting that adaptations may have a purpose (rather than just a consequence). This reflects a common challenge of communicating science – either in formal teaching or supporting public understanding.
The teacher or science communicator simplifies accounts and uses everyday ways of expressing ideas that an audience without specialist knowledge can readily engage with to help 'make the unfamiliar familiar'. However, the simplifications and approximations and short-cuts we use to make sure what is said can be understood (i.e., made sense of) by non-specialists also risks us being misunderstood.
What is the relationship between Albert Einstein and St. John the Baptist?
Why would someone seeking to communicate scientific ideas to a broad readership refer to St. John?
Spoiler alert: in a direct sense, there clearly is no relationship. St. John lived in Palestine two thousand years ago, was a preacher, and is not known to have had any particular interest in what we think of as physics or science more generally. Albert Einstein was a theoretical physicist, and probably the most famous scientist of the twentieth century, perhaps of all time.
It is fair to point out both were Jewish: John can be considered a Jewish prophet. There has been much speculation on Einstein's religious thought. Of Jewish background, he was subject to the Nazi's fascist policies in Germany and fled to spent much of his life in the U.S.A. Sometimes considered an atheist, Einstein did talk of God (as not playing dice for example – that is, not leaving room in the Universe for completely random events) but it is sometimes claimed he use the idea of God as a metaphor for some kind of pantheistic or general spiritual background to the universe. In general though, he stuck to physics, and campaigned on issues like world peace.
My posing this question was motivated by reading something written by Herman Weyl (1885 – 1955) who is described by Wikipedia as "a German mathematician, theoretical physicist and philosopher". In one of his writings Weyl referred to Hendrik Lorentz who (again according to Wikipedia) was "a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect".
This is how Weyl described Lorentz:
"the Dutch physicist H.A. Lorentz who, as Einstein's John the Baptist, prepared the way for the gospel of relativity."
Weyl, 1952/2016, pp.131-132.
Those studying physics at high levels, or reading about relativity theory, will probably have heard of the 'Lorentz transformations' that are used in calculations in special relativity.
An extended metaphor?
What Weyl is doing here is using a metaphor, or perhaps an analogy. In a metaphor a writer or speaker says that something is something else – to imply it has some attribute of that other thing.
In an analogy, one system is compared with another to show that there is, or to suggest that perhaps might be, a structural similarity. Usually analogies are presented as an explicit comparison (X is like Y: i.e., rather than 'Lorentz was Einstein's John the Baptist', perhaps 'Lorentz was like Einstein's John the Baptist in the sense that…')
As Weyl does not say Lorentz was like a John the baptist figure, or played a role similar to John the Baptist, but that he was "Einstein's John the Baptist" I would consider this a metaphor. However, it is an extended metaphor as the comparison is explained as justified because Lorentz "prepared the way for the gospel of relativity".
That could be seen as a second metaphor in that relativity is normally considered a theory (or two theories, special relativity, and general relativity), and not a gospel – a word that means 'good news'. So Weyl is saying that Lorentz prepared the way for the good news of relativity!
Making the familiar unfamiliar?
When I read this comment I immediately felt I appreciated the point that Weyl was seeking to make. However, I also felt that this was a rather odd comparison to make, as I was not sure how universally it would be understood.
Those communicating about science, whether as science teachers or journalists or (as here) scientists themselves looking to reach a general audience, have the task of 'making the unfamiliar (what people do not yet know about, and may indeed seem odd) familiar'. There are various techniques that can be used, and often these involve some form of comparison of what is being told about with something that is in some ways similar, and which is already familiar to the audience.
I attended 'Sunday school' from a young age (I think before starting day school if I recall correctly) at a London City Mission church, and later at a Methodist Church, where I became a Sunday school teacher before i went off to University. I therefore learnt quite a bit about Christianity. Anyone with such a background will have learnt that John the Baptist was a cousin of Jesus Christ, who preached 'the coming of the Lord' (i.e., the Jewish messiah, identified in Christianity with Jesus), and baptised Jesus in the River Jordan as he set out on his mission as a preacher and healer. John is said to have told his congregation to "prepare ye, the way of the Lord!" (the title of a song in the musical 'Godspell').
Someone knowing about Christianity in this way (regardless of whether they accept Christian teaching, or even the historical accuracy of the Baptism story) would likely immediately appreciate that just as John prepared the way for Jesus' ministry in first Century (CE) Palestine, so, according to Weyl, Lorentz prepared physics, laid important groundwork, for Einstein's work on relativity.
When you have the necessary background, such comparisons work effectively and quickly – the idea is communicated without the reader having to puzzle over and interpret the expressions "Einstein's John the Baptist" and "gospel of relativity" or deliberate on what is meant by 'preparing the way'. That is, the if the reader has the relevant 'interpretive resources' then understanding is an automatic process that does not require any conscious effort.
Culture-specific interpretive resources?
But I wondered what someone would make of this phrase ('Einstein's John the Baptist') if they did not have knowledge of the Bible stories? After all, in many parts of the world most people are not Christians, and may have little or no knowledge of Christian traditions. Did Weyl just assume everyone would have the background to appreciate his comparison, or did he assume he was only writing for an audience in certain parts of the world where this was common knowledge?
Certainly, as teachers, our attempts to help our students understand abstract ideas by making references to common cultural phenomena can fall flat if the learners are not familiar with those phenomena. It is counter-productive if the teacher has to interrupt their presentation on some abstract idea to explain the very comparison that was meant to help explain the scientific concept or principle. If you have no idea who 'John the Baptist' was, in what sense he 'prepared the way' for Jesus, or or how the term 'Gospel' came to be attached to the accounts of Jesus' life, then it is not so easy to appreciate what Lorentz was to Einstein's work from Weyl's prose. We can only make the unfamiliar familiar by using cultural references when we share those references with those we are communicating with.
Work cited:
Weyl, H. (1952/2016). Symmetry (New Princeton Science Library edition ed.). Princeton, New Jersey: Princeton University Press.
"If the muscles and other cells of the body burn sugar instead of oxygen…"
Do they think we cannot handle the scientific truth?
I should really have gone to bed, but I was just surfing the channels in case there was some 'must watch' programme I might miss, and I came across a screening of the film 'A few good men'. This had been a very popular movie at one time, and I seem to recall watching it with my late wife. I remembered it as an engaging film, and as an example of the 'courtroom drama' genre: but beyond that I could really only remember Tom Cruise as defence advocate questioning Jack Nicholson's as a commanding officer – and the famous line from Nicholson – "You can't handle the truth!".
This became something of a meme – I suspect now there are a lot of people who 'know' and use that line, who have never even seen the film and may not know what they are quoting from.
So, I though I might watch a bit, to remind myself what the actual case was about. In brief, a marine stationed at the U.S. Guantánamo Bay naval base and detention camp had died at the hands of two of his comrades. They had not intended to kill, but admitted mistreating him – their defence was they were simply obeying orders in subjecting a colleague who was not measuring up, and was letting the unit down, to some unpleasant, but ultimately (supposedly) harmless, punishment.
The film does not contain a lot of science, but what struck me was the failure to get some science that was invoked right. I was so surprised at what I thought I'd heard being presented as science, that I went back and replayed a section, and I then decided to see if I could find the script (by Aaron Sorkin*, screenplay adapted from his own theatre play) on the web, to see if what was said had actually been written into the script.
One of the witnesses is a doctor who is asked by the prosecuting counsel to explain lactic acidosis.
Burning sugar instead of oxygen?
The characters here are:
Capt. Jack Ross (played by Kevin Bacon) the prosecuting counsel,
Dr. Stone (Christopher Guest) and
Lt. Daniel Kaffee (Cruise's character).
On direct examination:
Ross: Dr. Stone, what's lactic acidosis?
Stone: If the muscles and other cells of the body burn sugar instead of oxygen, lactic acid is produced. That lactic acid is what caused Santiago's lungs to bleed.
Ross: How long does it take for the muscles and other cells to begin burning sugar instead of oxygen?
Stone: Twenty to thirty minutes.
Ross: And what caused Santiago's muscles and other cells to start burning sugar? [In the film, the line seems to be: And what caused this process to be speed up in Santiago's muscles?]
Stone: An ingested poison of some kind.
Later, under cross-examination
Kafee: Commander, if I had a coronary condition, and a perfectly clean rag was placed in my mouth, and the rag was accidentally pushed too far down, is it possible that my cells would continue burning sugar after the rag was taken out?
Stone: It would have to be a very serious condition.
What?
If a student suggested that lactic acid is produced when the muscles burn sugar instead of oxygen we would likely consider this an alternative conception (misconception). It is, at best, a clumsy phrasing, and is simply wrong.
Respiration
Metabolism is a set of processes under very fine controls, so whether we should refer to metabolism as burning or not, is a moot point. Combustion tends to be a vigorous process that is usually uncontrolled. But we can see it as a metaphor: carbohydrates are 'burnt' up in the sense that they undergo reactions analogous to burning.
But burning requires oxygen (well, in the lab. we might burn materials in chlorine, but, in general, and in everyday life, combustion is a reaction with oxygen), so what could burning oxygen mean?
In respiration, glucose is in effect reacted with oxygen to produce carbon dioxide and water. However, this is not a single step process, but a complex set of smaller reactions – the overall effect of which is
glucose + oxygen → carbon dioxide + water
Breaking glucose down to lactic acid also acts as an energy source, but is no where near as effective. Our muscles can undertake this ('anaerobic') process when there is insufficient oxygen supply – for example when undertaking high stamina exercise – but this is best seen as a temporary stop-gap, as lactic acid build up causes problems (cramp for example) – even if not usually death.
Does science matter?
Now clearly the science is not central to the story of 'A few good men'. The main issues are (factual)
whether the accused men were acting under orders;
(ethical)
the nature of illegal orders,
when service personal should question and ignore orders (deontology) given that they seldom have the whole picture (and in this film one of the accused men is presented as something of a simpleton who viewer may suspect should not be given much responsibility for decision making),
whether it is acceptable to use corporal or cruel punishment on an under-performing soldier (or marine) given that the lives of many may depend upon their high levels of performance (consequentialism, or perhaps pragmatics)…
There is also a medical issue, regarding whether the torture of the soldier was the primary cause of death, or whether there was an underlying health issue which the medical officer (Stone) had missed and which might also explain the poor performance. [That is a theme which featured large in a recent very high profile real murder case.]
Otherwise the film is about the characters of, and relationships among, the legal officers. Like most good films – this is film about people, and being human in the world, and how we behave towards and relate to each other.
The nature of lactic acidosis is hardly a key point.
But if it is worth including in the script as the assumed cause of death, and its nature relevant – why not get the science right?
Perhaps, because science is complicated and needs to be simplified for the cinema-goer who, after all, wants to be entertained, not lectured?
Perhaps there is no simple account of lactic acidosis which could be included in the script without getting technical, and entering into a long and complicated explanation.
In teaching science…
But surely that is not true. In teaching we often have to employ simplifications which ignore complexity and nuance for the benefit of getting the core idea across to learners. We seek the optimal level of simplification that learners can make good sense of, but which is true to the core essence of the actual science being discussed (it is 'intellectually honest') and provides a suitable basis for later more advanced treatments.
It can be hard to find that optimum level of simplification – but I really do not think that explaining lactic acidosis as burning sugar instead of oxygen could be considered a credit-worthy attempt.
Dr. Stone, can we try again?
What about, something like:
Dr. Stone, what's lactic acidosis?
It occurs when the body tissues do not have sufficient oxygen to fully break down sugar in the usual way, and damaging lactic aid is produced instead of carbon dioxide and water.
I am sure there are lots of possible tweaks here. The point is that the script did not need to go into a long medical lecture, but by including something that was simply nonsensical, and should be obviously wrong to anyone who had studied respiration at school (which should be everyone who has been to school in the past few decades in many countries), it distracts, and so detracts, from the story.
All images from 'A few good men' (1992, Columbia Pictures)
* I see that ("acclaimed screenwriter") Aaron Sorkin is planning a new live television version of 'A Few Good Men' – so perhaps the description of lactic acidosis can be updated?
I have recently posted on the blog about having been viewing some of the court testimony being made available to the public in the State of Minnesota v. Derek Michael Chauvin court case (27-CR-20-12646: State vs. Derek Chauvin).
Now you talked quite a bit about physics in your direct testimony, agreed?
Yes
And you would agree that physics, or the application of physical forces, is a constantly changing, er, set of circumstances.
I did not catch what you said.
Sure. You would agree with me, would you not, that when you look at the concept may be considered as the sum of all its associations.<em>Read about concepts</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/concepts/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">concepts of physics, these things are constantly changing, right?
Yeah, all of science is constantly changing.
Constant! I mean,
Yes.
in milliseconds and nanoseconds, right?
Yes.
And so if I put this much weight [Nelson demonstrating by shifting position] or this much weight [shifting position], all of the formulas [sic] and variations, will change from second to second, from millisecond to millisecond, nanosecond to nanosecond, agreed.
I agree.
Similarly, biology sort of works the same way. Right?
Yes.
My heart beats, my lungs breathe [sic], my brain is sending millions of signals to my body, at all times.
Correct.
Again, even, I mean, faster than the speed of light, right?
Correct.
Millions of signals every nanosecond, right?
Yes.
Day 9. 27-CR-20-12646: State vs. Derek Chauvin
Agreeing – but talking about different things?
The first thing that struck me here concerns what seems to me to be Mr Nelson and Dr Tobin talking at cross-purposes – that neither participant acknowledged (and so perhaps neither were aware of).
I think Nelson is trying to make an argument that the precise state of Mr George Floyd (who's death is at the core of the prosecution of Mr Chauvin) would have been a dynamic matter during the time he was restrained on the ground by three police officers (an argument being made in response to the expert's presentation of testimony suggesting it was possible to posit fairly precise calculations of the forces acting during the episode).
This seems fairly clear from the opening question of the exchange above:
Now you talked quite a bit about physics in your direct testimony, agreed? … And you would agree that physics, or the application of physical forces, is a constantly changing, er, set of circumstances.
However, Dr Tobin does not hear this clearly (there are plexiglass screens between them as COVID precautions, and Nelson acknowledges that he is struggling with his voice by this stage of the trial).
Nelson re-phrases, but actually says something rather different:
You would agree with me, would you not, that when you look at the concept may be considered as the sum of all its associations.<em>Read about concepts</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/concepts/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">concepts of physics, these things are constantly changing, right?
['These things' presumably refers to 'the application of physical forces', but if Dr Tobin did not hear Mr Nelson's previous utterance then 'these things' would be taken to be 'the concept may be considered as the sum of all its associations.<em>Read about concepts</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/concepts/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">concepts of physics'.]
So, now it is not the forces acting in a real world scenario which are posited to be constantly changing, but the concept may be considered as the sum of all its associations.<em>Read about concepts</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/concepts/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">concepts of physics. Dr Tobin's response certainly seems to make most sense if the question is understood in terms of the science itself being in flux:
Yeah, all of science is constantly changing.
Given that context, the following agreement that these changes are occurring "in milliseconds and nanoseconds" seems a little surreal, as it is not quite clear in what sense science is changing on that scale (except in the sense that science is continuing constantly – certainly not in the sense that canonical accounts of concept may be considered as the sum of all its associations.<em>Read about concepts</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/concepts/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">concepts shift at that pace: say, in the way Einstein's notions of physics came to replace those of Newton).
In the next exchange the original context Nelson had presented ("the application of physical forces, is … constantly changing") becomes clearer:
And so if I put this much weight [Nelson demonstrating by shifting position] or this much weight [shifting position], all of the formulas and variations, will change from second to second, from millisecond to millisecond, nanosecond to nanosecond, agreed.
I agree.
As a pedantic science teacher I would suggest that it is not the formulae of physics that change, but the values to be substituted into the system of equations derived from them to describe the particular event: but I think the intended meaning is clear. Dr Tobin is a medical expert, not a physicist nor a science teacher, and the two men appear to be agreeing that the precise configurations of forces on a person being restrained will constantly change, which seems reasonable. I guess that is what the jury would take from this.
If my interpretation of this dialogue is correct (and readers may check the footage and see how they understand the exchange) then at one point the expert witness was agreeing with the attorney, but misunderstanding what he was being asked about (how in the real world the forces acting are continuously varying, not how the concept may be considered as the sum of all its associations.<em>Read about concepts</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/concepts/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">concepts of science are constantly being developed). Even if I am right, this does not seem problematic here, as the conversation shifted to the intended focus quickly (an example of Bruner's 'constant transnational calibration' perhaps?).
However, this reminds me of interview</div><div class=glossaryItemBody>Research interviewing involves a class of techniques for collecting data based upon engaging informants in conversations with various levels of structuring<em>Read more about research interviews</em><br/></div>" href="https://science-education-research.com/reference/site-glossary/interview/" target="_blank" data-mobile-support="0" data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]' tabindex='0' role='link'data-bgcolor="#e8e8e8"data-tcolor="#73874d">interviews with students I have carried out (and others I have listened to undertaken by colleagues), and of classroom episodes where teacher and student are agreeing – but actually are talking at cross purposes. Sometimes it becomes obvious to those involved that this is what has happened – but I wonder how often it goes undetected by either party. (And how often there are later recriminations – "but you said…"!)
Simplifying biology?
The final part of the extract above also caught my attention, as I was not sure what to make of it.
My heart beats, my lungs breathe, my brain is sending millions of signals to my body, at all times.
Correct.
Again, even, I mean, faster than the speed of light, right?
Correct.
Millions of signals every nanosecond, right?
Yes.
How frequently do our brains send out signals?
I am a chemistry and physicist, not a biologist so I was unsure what to make of the millions of signals the brain is sending out to the rest of the body every nanosecond.
I can certainly beleive that perhaps in a working human brain there will be billions of neutrons firing every nanosecond as they 'communicate' with each other. If my brain has something like 100 000 000 000 neurons then that does not seem entirely unreasonable.
But does the brain really send signals to the rest of the body (whether through nerves or by the release of hormones) at a rate of nx106/10-9 s-1 ("millions of signals every nanosecond"), that is, multiples of 1015 signals per second, as Mr Nelson suggests and Dr Tobin agrees?
Surely not? Dr Tobin is a professor of medicine and a much published expert in his field and should know better than me. But I would need some convincing.
Biological warp-drives
I will need even more convincing that the brain sends signals to the body faster than the speed of light. Both nervous and hormonal communication are many orders of magnitude slower than light speed. The speed of light is still considered to be a practical limit on the motion of massive objects (i.e., anything with mass). Perhaps signals could be sent by quantum entanglement – but that is not how our nervous and endocrine systems function?
If Mr Nelson and Dr Tobin do have good reason to believe that communication of signals in the human body can travel faster than the speed of light then this could be a major breakthrough. Science and technology have made many advances by mimicking, or learning from, features of the structure and function of living things. Perhaps, if we can learn how the body is achieving this impossible feat, warp-drive need not remain just science fiction.
A criminal trial is a very serious matter, and I do not intend these comments to be flippant. I watched the testimony genuinely interested in what the science had to say. The real audience for this exchange was the jury and I wonder what they made of this, if anything. Perhaps it should be seen as poetic language making a general point, and not a technical account to be analysed pedantically. But I think it does raise issues about how science is communicated to non-experts in contexts such as courtrooms.
This was an expert witness for the prosecution (indeed, very much for the prosecution) who was agreeing with the defence counsel on a point strictly contrary to accepted science. If I was on a jury, and an expert made a claim that I knew was contrary to current well-established scientific thinking (whether the earth came into being 10 000 years ago, or the brain sends out signals that travel faster then the speed of light) this would rather undermine my confidence in the rest of their expert testimony.
I realised that there was something fascinating about the forensic nature of legal proceedings some years ago (1985) when I saw a television dramatisation of the tribunal into the death of Steve Bantu Biko in police custody in (then still apartheid) South Africa. Although this was a re-enactment, it used actual transcripts to present a reconstruction.
Although like most people I was disgusted with apartheid, I probably would not have known about Steve Biko if it had not been for Peter Gabriel's (1980) anthem ('Biko') protesting his killing – that was the hook that got me to take a look at the film. Although expecting I might find it dry or distressing – it was fascinating. Something that I intended to watch almost out of a sense of liberal duty was totally engrossing.
I have recently spent some time looking at footage of the trial of former police office Derek Chauvin regarding the death of George Floyd. (A case which of course has parallels with Biko's death.) This came from discovering I had access to a whole TV channel (currently) dedicated to showing the court case. I have largely moved from that (as I had less interest in all the commentary which added little to the court 'action'*) to reviewing some of the daily footage from the courtroom available on line.
(* I was especially unimpressed by the trailers for forthcoming cases in U.S. States with the death penalty, where the show anchor gleefully told viewers we could watch verdicts where we would see the the accused as they found out if they were to live or die.)
Scene from inside the courtroom: Derek Chauvin represented by his attorney Eric Nelson
The application of science
In this particular case there is a good deal of physics, chemistry and biology (and indeed their interactions) being presented and argued over. I am not sure I would encourage children to watch (and certainly not to approach as an alternative form of entertainment) such serious proceedings – but any who are watching the expert testimony being presented may appreciate a lot about the nature of science (and in particular how data does not become evidence in isolation ). There is a potential counter here to all those TV shows where the whole history of the universe is unproblematically pieced together from some DNA collected by a detective offering a suspect a drink of water. (Okay, I exaggerate, if only a little.)
I initially, accidentally, fell upon coverage of pre-trial arguments about what evidence might be admissible in the forthcoming trial – and started to see how the defence may be offering a story quite inconsistent with the widely accepted narrative (based on the much shared film of the incident). I realised that despite thinking I was the kind of person who tries to always look at different perspectives and seek alternative understandings, and reserve judgement until it is due, I had (without being aware of it) already decided what had happened in this case, and in my own head the presumption of innocence had not really been applied.
This then led to me watching some of the footage of jury selection. This is a process I had been aware of, but had not considered in that much detail – and had certainly not fully appreciated why it might take so much time. After all, if I already had a pretty strong assumption of guilt, and I do not even live on the same continent, selecting people from the local area who have lived through the aftermath (protests and riots) and could put aside everything they had previously learnt, to focus purely on what was presented at trial, was not going to be easy.
There is a television programme, 'Would I lie to you?', where celebrities are given tall autobiographical tales to tell, some of which are true (though I suspect sometimes embellished in the telling) and where points are awarded to the two sides according to whether a person on one team misleads the other team into incorrectly determining 'truth or lie'. This came to mind in watching jury selection.
As the potential jurors were interviewed I found myself forming hunches of when the judge might excuse someone (who clearly was not going to be able to be fair to both sides) or when one of the attorneys might ask for a potential juror not to be selected to sit. Of course, there is a very big difference in nature between a popular entertainment show where some people act out the telling of a 'lie' (which is not really a lie, as there is no intention to mislead beyond the point of reveal within the game), and the very serious matter of jury selection, but the process of thinking about 'what will they think about this person's presentation?' in observing these different events seemed very similar.
Clearly, the Chauvin prosecution is a very high profile case, given the viral video of the incident and its importance (especially given its wider context as just one more in a continuing sequence of incidents with similar outcomes) in triggering worldwide condemnation of racism and the emergence of the Black Lives Matter movement.
However, my interest was piqued less by the highly charged public interest in this particular case (important as it is even in its own terms – a man has died in police 'care'; another may be incarcerated for 20 years or more depending on the verdict) than as the window into a real court. I was fascinated by aspects of the legal process. One feels very familiar with the U.S Court system though fictional works (Ally McBeal, The Good Wife/The Good Fight, etc.) but that is entertainment, and accounts of the legal process are very much condensed.
Interpreting data as evidence for a theory
I have always felt an interest in the law, and I think that is not surprising, given that the law acts as a set of formal guidelines (on process, and what is admissible and so forth), and the legal process is forensic, and evidence based, and adopts arguments to suggest how data can be construed as evidence within particular narratives of events.
This all seems parallel to science, and research more generally.
I have even used the law as an analogy in my teaching to suggest how one difference between the kind of theory-directed research which offers generalisable findings and is suitable for publication and context-directed research that may inform a practitioner's day-to-day decisions in the classroom as these can be seen to have a different burden of proof akin to the difference between criminal and civil courts (Taber, 2013). That is:
theory-directed research (claimed to be generalisable and worth reporting in the research literature) – should make its case beyond reason
context-directed research (such as action research carried out to address a local issue) – should make its case on the balance of probabilities, that is, (local) action should be informed by what the evidence suggests is most likely the case
Moreover, in many cases (and certainly very much in the Chauvin trial) science is heavily involved in making arguments and developing the cases for prosecution and/or defence.
The examination of witnesses in trials has a strong, if warped, parallel with research interviewing. The warping comes in because in research an interviewer should look to be unbiased and should be seeking 'the truth' as their informant understands it. In a trial, however, the lawyers for the two sides are each seeking to build a case, and so to ask questions that seek answers most in keeping with the scenario they are looking to establish as best representing the actual situation around an alleged crime.
So, there is much of interest in terms of how science is applied in expert testimony, but perhaps also some lessons from the advocates in how not to do science by seeking to re-shape all the data to fit one's hypothesis.
Actress Francesca Tu playing an 'ugly chemist', apparently.
The 1969 film 'The Chairman' (apparently released in the UK as 'The Most Dangerous Man in the World') was just shown on the TV. I had not seen it before, but when I noticed it was on I vaguely recalled having heard something about it suggesting it was a film worth watching, so thought I would give it a try. And it had "that nice Gregory Peck" in it, which I seem to recall was the justification given for one of my late wife's sweet little Aunties going to see 'The Omen' (wasn't that also about the The Most Dangerous Man in the World?).
Nobel prize winner AND man of action
Dr John Hathaway (played by Gregory Peck): scientist and international man of mystery
Peck plays a Nobel laureate chemist, so I got interested. He had received a letter from a Chinese scientist, an old mentor who had worked with him at Princeton, warning him not to go to visit him in China, which (a) piqued his interest as (i) he had had no contact with the colleague for a decade, and (ii) he had no plans to go to China, and (b) told us viewers he would be off to China.
Peck's character, Hathaway, is an American who is currently a visiting professor at the University of in London. He contacts his embassy, suspecting there must be something of international significance in the message.
Hathaway's love interest (played by Anne Heywood) is seen teaching in the biophysics department
It transpires that this Nobel prize winning chemist had some kind of background in "the game" – intelligence work (of course! Well, at least this gets away from the stuffy stereotype of the scientist who never leaves the lab.), but had reached an epiphany three years earlier when his wife had been killed in a road accident while he was driving, and the experience of being with her as she died had led to him deciding that every life was unique and precious (as he later explained to Mao Zedong, the eponymous Chairman of the title) and he would no longer take on a job that would oblige him to kill. (Later in the film Hathaway seemed to have forgotten his high principles when he accepted a pistol as he made an escape in a stolen armoured car.) The intelligence communities had become aware that China had identified a natural product that could be extracted in tiny quantities, an enzyme which allowed any crop to be grown under any conditions.
The film seemed to be intended to make some serious points about detente, the cold war, the cultural revolution and the cult of Mao, and political and moral imperatives.
It is the responsibility of all to cultivate themselves, and study Marxism-Leninism deeply. / [Thinks: Sure, as soon as we've finished cultivating this rice.]The allies argue that China will keep the new discovery to itself and use it to bring developing countries with food shortages into its sphere of influence, and Hathaway seems motivated to ensure all of humanity should share the benefits, thus he accepts the mission to go to China; later Mao agrees to provide a written promise that if Hathaway helps in the research then he can leave China at any time he likes and take with him whatever information he wishes to share with the world.
For the rest of the film to make any sense, Hathaway and the viewer have to assume that the promise and document will not be honoured (and it seems to be assumed that a character simply suggesting this is all Hathaway, or indeed any of us, need to be convinced of this). Yet, (SPOILER ALERT) when Hathaway is safely back in London, and has decoded the structure, he is told that the Western authorities have decided not to share the discovery.
I was not sure what a young audience who do not remember the context might make of some aspects of the film. We are told that the operation to obtain the enzyme, operation Minotaur *, has according to the US officer in charge cost half a billion federal dollars (which seems a lot for 1969, even allowing for some exaggeration) and was supported by the UK with a contribution a British intelligent officer suggests was likely "two pounds ten" (i.e., £2.50).
I wondered whether Chinese agents actually operated so easily in moving into and out of Hong Kong as is suggested, and there was some interesting brief news footage playing on a hotel television suggesting (British) Hong Kong police were responding to civil unrest in a way that does not seem so different from contemporary reports under the already notorious 2020 Hong Kong national security law.
Anyway, I will try and avoid too many plot spoilers, but suffice to say I was interested and intrigued in how matters would pan out for the first three quarters of the film (until people started firing guns and throwing grenades, at which point I lost any investment I'd had in what would happen.)
Science in the media in 1969
The science in the film was far-fetched, but perhaps not too far fetched for a general audience in 1969. 1969 was after all, a different age. (In 1969 the Beatles were still together, 'In the Court of the Crimson King' was released, and NASA's landing on the moon showed just what the USA could achieve when a President believed in, and encouraged, and resourced, the work of scientists and engineers.)
A transmitter made of undetectable plastic parts, suppposedly
Hathaway was bugged (through a sinus implant) such that his US /UK handlers (and USSR observer) could hear everything he said and everything said to him from half a world away through a bespoke satellite that the Chinese had not noticed recently appearing over their territory. The Americans initially had serious trouble with signal:noise and just made out the odd consonant, and so could not understand any speech, but a UK intelligence officer suggested simply filling in the gaps with uniform white noise, which, amazingly, and (even more amazingly) immediately at first attempt, gave a much cleaner sound than I can get on FaceTime or Zoom or Skype today (Implied message: the British may be the poor relatives, but have the best ideas?)
High stakes communication
What Hathaway did not know (but perhaps he should have been paying more attention when he was told the implanted transmitter was a 'remedy' in case the Chinese would not let him leave the country?) was that the implanted transmitter also had an explosive device that could be used if he needed to be terminated.
Indeed there was supposedly enough plastic explosive that when Hathaway was invited to meet Chairman Mao (was he meant to be 'the most dangerous man in the world'?) it raised the issue of whether the device should be used to remove the Chairman as he played table tennis with Hathaway (asking us to believe that democratic governments might sanction the violent summary execution of perceived enemies, without due legal process, in foreign lands) *.
Is it stretching credibility to believe that democratic governments would sanction the violent summary execution of perceived enemies, without due legal process, on foreign soil?
The command code to explode the device was stored on magnetic tape that took over thirty seconds to execute the instructions (something that seems ridiculous even for 1969, and was presumably only necessary to provide faux tension at the point where the clock counts down and the audience are supposed to wonder if the British and Americans are going to have to kill the film's star off before the movie is over).
Equally ridiculous, the implant supposedly had the same density as human tissue so that it would not show up on X-rays. (A wise precaution: when in Hong Kong, Hathaway is lured to some kind of decadent, Western, casino-cum-brothel where Chinese agents manage to covertly X-ray him from the next room as he enjoys a bowl of plain rice with a Chinese intelligence officer – quite a technical feat).
Of course, human tissue is not all of one 'density' (in the sense of opaqueness to X-rays), or else there would be little point in using X-rays in medical diagnosis – actually a sinus should show up on an X-ray as an empty cavity!
Would blocked sinuses show on an X-ray?
Highly technical information appeared on screens at the listening post as displays little more complex than sine waves – not even the Lissajous figures so popular with 1970s sci-fi programmes.
I think it's just the carrier wave, sir
At one point Hathaway broke into a room through a thick solid metal floor by using just a few millilitres of nitrohydrochloride acid (aqua regia) that was apparently a standard bench reagent in the Chinese biochemistry laboratory (these enzymes must be pretty robust, or perhaps Professor Soong had a side project that involved dissolving gold), and which Hathaway was quite happy to carry with him in a small glass bottle in his jacket pocket. The RSC's Education in Chemistry magazine warns us that "because its components are so volatile, [aqua regia] is usually only mixed immediately prior to use". Risk assessment has come on a lot since Dr Hathaway earned his Nobel.
The focal enzyme was initially handled rather well – the molecular models looked convincing enough, and the technical problem of scaling up by synthesising it seemed realistic. The Chinese scientist could not produce the enzyme in quantity and hoped Hathaway could help with the synthesis – a comparison was made with how producing insulin originally involved the sacrifice of many animals to produce modest amounts, but now could be readily made at scale. I seem to recall from my natural products chemistry that before synthetic routes were available, sex hormones were obtained by collecting vast amounts of 'material' from slaughterhouses and painstakingly abstracting tiny quantities – think the Curies, but working with with tonnes of gonads rather than tonnes of pitchblende.
Before Hathaway had set out on his mission he had pointed out that the complexity of an enzyme molecule was such that he could never memorise the molecular structure as it would contain anything from 3000 to 400 000 atoms. So, the plot rather fell apart at the end (SPOILER ALERT) as he brings back a copy of Mao's little red book, in which his mentor had hidden the vital information – as the codes for three amino acids.
Ser – Tyr – Pro
Hm.
Beauty and the chemist
You are beautiful, just like your mother – but OBVIOUSLY not as clever as your dad.
But, what sparked me to wrote something about this film, was some dialogue which brought home to me just how long ago 1969 was (I was still in short trousers – well, to be honest, for about half the year I am still in short trousers, but then it was all year round). Hathaway is flown to China from Hong Kong, and on arrival is met by the daughter of his old mentor:
Soong Chu (Francesca Tu): I am Professor Soong's daughter
Dr. John Hathaway (Peck): You look a great deal like your beautiful mother.
Soong Chu: Not I. I am just an ugly chemist
Hathaway: I read your recent paper on peptides. I thought it was brilliant – for a woman.
Soong Chu: Oh, I agree, but my father helped a great deal.
Working in the dark to avoid any more comments on her looks?
I was taken aback by the reference to just being an ugly chemist, and had to go back and check that I'd heard that correctly. Was the implication that one could not be beautiful, and a chemist? Nothing more was said on the topic, but that seemed to be the implication. And what is meant by being 'just' a chemist?
Hathaway's comment that Soong Chu's paper had been brilliant, was followed by a pause. Then came "…for a woman". Did he really say that?
Not bad for a girl
I was waiting for the follow-up comment which would resolve this moment of tension. This surely had to be some kind of set up for a punch line: "It would have been beyond brilliant for a man", perhaps.
But no, Soong Chu just agreed. There did not seem to be intended to be any tension or controversy or social critique or irony or satire there. So much for Soong Chu's membership of the Red Guard and all the waving of the thoughts of the Chairman (she would have known that "Women represent a great productive force in China, and equality among the sexes is one of the goals of communism").
"The red armband is the most treasured prize in China…[representing] responsibility…[as] a leader of our revolution"Soong Chu had needed the help of her father to prepare her paper, but he had presumably declined to be a co-author, not because his input did not amount to a substantial intellectual contribution (the ethics of authorship have also come on a bit since then), but because his daughter was a woman and so not able to stand on her own two feet as a scientist.
This dialogue is not followed up later in the film.
So, this is not planting a seed for something that will later turn out to be of significance for character development or plot, or that will be challenged by subsequent scenes. It is not later revealed that Soong Chu has a parallel career as Miss People's Republic of China (just as Hathaway is a chemist and also a kind of James Bond figure). Nor does it transpire that Professor Soong had been senile for many years and all of his work was actually being undertaken for him by his even more brilliant daughter.
Sadly, no, it just seems to be the kind of polite conversation that the screenwriters assumed would be entirely acceptable to an audience that was presumably well aware that females cannot be both beautiful and scientists; and that women need help from men if they are to be successful in science.
Times have changed … I hope.
* Interestingly, I've now found a poster for the film which seems to suggest that the whole purpose of the operation was not to acquire the enzyme structure at all, but to get Hathaway close enough to Mao to assassinate him.
Getting viewers to watch the film under false pretences
This seems to describe a very different cut to one I watched – where the audience with Mao seems to have surprised everyone, and the senior intelligence officers contacted their governments to alert them of this unexpected opportunity!
It would seem (rightly) indecent for your great great grandfather to have procreated with your sister – but if you could go back far enough in your family tree you would surely find even more extreme examples of intergenerational couplings!
Skulls images by Parker_West from Pixabay
Some approaches to conceptualising speciation may by definition impose sharp distinctions: in one version of cladistics it is assumed that at any speciation event the ancestor species ceases to be extant, and the new species comes into existence at one moment in time – if members of (what was) the ancestral species happily carry on living their lives despite this conventional extinction, as a new species branches off from the ancestral line, they are judged now to be members of another new species. That is, in this system a species is never considered to give rise to a new species and also continue, but rather transitions into two new species, even if one contains individuals indistinguishable from those in the ancestral line (LaPorte 2004). However, I am going to take the position here that if experts in the field cannot distinguish specimens as being from different species then it is reasonable to consider those specimens as conspecific.
To take an example close to home, consider the species Homo sapiens. Every human alive today had parents who were, like themselves, specimens of the species Homo sapiens. These parents also had parents who were specimens of the species Homo sapiens. So did their parents – and (to avoid this text becoming extremely tedious) so on, through a large number of generations. However, modern humans are understood to have evolved from earlier hominids (who in turn evolved from non-human primates, who evolved from non-primate mammals, who evolved from non-mammalian chordates, and so forth.)
A thought experiment about ancestry
So, consider a thought experiment where scientists had physical evidence of the full ancestry of someone, some specimen of Homo sapiens, alive today – bones, DNA, whatever. It is only a thought experiment, so it only has to be possible in principle, not feasible in practice. And forensic science today achieves things that might have seemed fantastic just a few decades ago – so who can say what might become feasible in time?
Experts in anatomy or genetics would agree that the generation of the parents of our human friend were Homo sapiens, as were the previous generation, and the generation before that, and… However, at some point many, many generations back, the experts would agree that the scientific evidence showed these more distant ancestors were not Homo sapiens, but something else – perhaps Homo heidelbergensis.
We would be going back something of the order of tens of thousands of generations. Perhaps (for the sake of this thought experiment – the actual numbers are not critical to the argument) all the experts agree that the ancestors in generation n-14000 (n minus fourteen thousand, where n is the current generation, our living person) were members of our species, Homo sapiens, and perhaps these experts also all agree that the ancestors in generation n-17000 were a different species, not Homo sapiens: but where does this transition occur?
It seems unlikely that the experts would be able to agree, based on clear distinctions in the material evidence (even if we assumed the evidence available, as this is a thought experiment), that ancestors in generation n-15777 (for example) were the earliest ancestors who were members of Homo sapiens and that the ancestors in generation n-15778 were members of a different species.
Gradual change
This is not simply unlikely because the experts would not agree as some would be more expert than others, and so be more likely to get things right: it is simply that the distinctions between species are not sudden and abrupt, but occur over time. Those transitions may often appear rapid when looking at the geological record, in terms of what is sometimes called 'deep time', but even allowing that evolution may not be as gradual and even as was once widely considered (Gould and Eldredge 1993/2000), the shift between distinct species is gradual in terms of our experience of the natural world. Our lives occupy a tiny period in the vastness of the history of the biota on Earth, so we experience the living things in our environment as if a single cross-section of a cone of biological development.
We are in effect living upon one cross-section, one microtome slice as it were, of deep-time – and so species appear as discrete kinds (Figure from Taber, 2013/2017.)
A compromised geometric progression?
Before moving on, it is worth highlighting the absurdity of extrapolating what seems commonplace on a 'local' (temporal) scale to a geological scale. Most people have 2 (21) parents, who were probably alive at the same time (i.e., their lives must have overlapped for them to be parents, unless there was some cryogenic storage of sperm or eggs – something that is now possible and means a very small proportion of people alive today have been conceived at a time when only one biological parent was alive), and 4 (22) grandparents whose lives nearly always overlapped in time, and 8 (23) great-grandparents whose lives probably overlapped in time… We might be tempted to generalise to having 2n ancestors if we go back n generations.
This pattern does not necessarily repeat indefinitely however. So, the British Head of State, at the time of writing, is Queen Elizabeth II. Two of her great-great grandparents were Queen Victoria and her escort Prince Albert. Elizabeth is married to Prince Philip. Two of his great-great grandparents were (also) Queen Victoria and Prince Albert. The Children of the current Queen (Charles, Anne, Andrew and Edward) therefore do not have a full, unique set of great-great-great grandparents, as Victoria and Albert each occupy positions on their family tree that could in principle have been filled by two different people (although that of course, would not have given rise to the existence of the particular individuals Charles, Anne, Andrew and Edward who are alive today).
It is a common view that the degree of inbreeding among the royal houses of Europe was responsible for the instances of certain medical conditions among the royals. Indeed, haemophilia was referred to as 'the royal disease'
Finding a mate
Although marriage and breeding within the extended family has been particularly noted among royalty, it was by no means their exclusive practice. In highly stratified societies where marrying above or below one's supposed rank was not acceptable, the range of potential mates in one's social circle might be very limited (as reflected in novels of the likes of Jane Austen).
Marrying relatives who were not immediate family was common and often productive. Charles Darwin married a cousin, Emma Wedgewood, which led to a very happy marriage, and some highly achieving offspring. Charles and Emma shared a grandfather – Josiah Wedgwood (the famous potter) – and grandmother. Social circle and extended family could overlap considerably.
A trivia quiz question might be:
How was John Allen Wedgwood able to legally marry two of his cousins on the same day? **
For much of human pre-history people lived in small groups where the range of potential mates would have been severely limited, leaving aside questions of social status. Indeed it is possible that the common taboo on sexual relations with very close relatives, i.e. incest, developed in a context where the number of feasible candidates for a mate was often very small.
A paradox? You have more human ancestors than the number of people who have ever lived
Returning, then, to our thought experiment. If each of their theoretical possible ancestors in generation n-15777 were discrete, individual, specimens (of whatever species) then our contemporary subject would have 215777 ancestors in that generation. That is a number vastly greater that the number of people living today (which is less than 233) or indeed who have ever existed – and is even vastly greater than estimates of the number of particles in the whole universe! (One estimate for the total number of quarks plus electrons is 'only' around 2268.) Some estimates for the size of the early Homo sapiens population are around 214 – rather less than 215777!
The vast discrepancy here then comes from assuming that the number of ancestors doubles in each generation. Most people have two parents, four grandparents, and eight great grandparents – but if one goes back a large number of generations there must have been considerable redundancy in the sense of individual ancestors taking up a number of positions on one's personal family tree. And we cannot even assume these multiple roles fall within the same generation.
The notion that anyone alive today would have all their ancestors from generation n-15777 alive at the same time is unreasonable.
If we assume that through most of human history the time lapse between generations was largely in a range 15-25 years (and clearly there will have been plenty of children born to parents younger than 15 and older than 25, so this is a conservative range) then it becomes obvious that at the time when one of our ancestors in generation n-15777 was alive, so were many of our ancestors in a wide range of other generations.
If the mean gap between generations was 20 years, then 15 777 generations ago was about 315 540 years ago. At the same time a line of descent with an average gap between generations of 15 years would be a little more than 21 036 generations ago, and a line of descent with an average gap between generations of 25 years would be 12 622 generations ago.
A schematic representation of the distribution of a person's ancestors living c.316 000 years ago in terms of how many generations separate them from that person. Many (most) ancestors will be represented many times (by different lines of descent) across a spread of points in the distribution.
It may seem strange to think that some of the ancestral pairings that led to us were between individuals that from our (temporally reversed) perspective were in generations that were hundreds or perhaps even thousands apart***: but of course the point is they were alive at the same time.
A highly simplified scheme showing descent along only two lines. Using the simplified example that people are born when their mother is 18 but their father is 24 (clearly there will normally be much variation in any 'branch' of any 'tree') it does not take many generations before ancestors alive (and of reproductive age) at the same time can be considered to be from different generations.*** Bearing in mind that we all have far fewer direct ancestors than potentially unique places on the 'tree', we could in principle trace many of our ancestors through multiple routes relating to different generations. In this simplified scheme the person's father's father's father is also their mother's mother's mother's father. So the same person could be your great-grandfather and also your great-great-grandfather. M = mother; FF = father's father; MMMF = mother's mother's mother's father, etc.
You are a member of the 15 778th generation of Homo sapiens, and you are a member of the 15 779th generation of Homo sapiens, and you are a member of the 15 777th generation of Homo sapiens, and…
By the same (or, if you prefer, the reverse) logic, even if we were (adopting a cladistic approach) able to pinpoint a precise moment in time when Homo sapiens appeared, generation 'Homo sapiens 1', then a person alive today would not by comparison be unequivocally in generation 'Homo sapiens 15778' (or whatever), at least, not unless we adopted a convention to count down through a particular line (e.g., always the mother). Rather, they would be in a hybrid generation with a wide range, say generation 'Homo sapiens 11 246-to-19 975', or whatever.
As a final observation, a common definition of species refers to breeding populations that can produce viable (fertile) offspring. If the distinction between Homo sapiens and, say Homo heidelbergensis, is a gradual shift and not a sharp cut off, then the question of interbreeding between co-existing species is somewhat avoided: but there is much evidence that our ancestors interbred with Neanderthals, even though they are traditionally considered to be a distinct species (Homo neanderthalensis).
Waking up a different species
So the biological species concept, whilst being extremely useful in science, would seem to either be somewhat arbitrary (if we adopt a cladistics perspective, and just define by fiat specific speciation events at which point old species become extinct and new ones are said to come into existence), or to have rather fuzzy edges.
The cladistic perspective keeps things rather nice and tidy but it would seem a bit like living in Europe during the restoration, when a person could go to bed an orthodox believer and wake up the next day a heretic because the sovereign had decided to switch the National faith from Catholicism to Protestantism (or vice versa). The person had not changed, but the definitions had. A helpful perspective, perhaps, is to treat the notion of biological species as a scientific hypothesis (Knapp 2017), in that when a scientist proposes a species this is a hypothesis about a certain regularity in the natural world: a hypothesis which is then the basis for further investigation.
** The answer does not relate to a tragic wedding-reception death followed by an indecently short whirlwind romance, but rather that the Rev. Wedgwood officiated at the wedding of his cousin Emma to his cousin Charles.
*** Of course, by definition the couple were in the same generation back along the line of descent they shared, but possibly in very different generations back along alternative lines of descent. So, the individual highlighted with the pink circle in the preceding figure has children with two different partners in the ancestral 'tree' (really, a network) as MMMMMMMM mating with MMMMMMMF, and as FFFFFM mating with FFFFFF. In both cases she is the same number of generations back as her partner in terms of their child on the particular ancestral line, BUT she is both a great-great-great-great grandmother and a great-great-great-great-great-great grandmother of the same individual. So in that sense, she belongs to two different generations. That is only considering 'fruitful' couplings that led to an offspring in the direct ancestory of some individual. There will clearly be many couplings that did not lead to offspring among someone's ancestors (or indeed no offspring at all) where the couple concerned only appear in the ancestral 'tree' of some individual in different generations.
Sources cited:
Gould, S. J., & Eldredge, N. (1993/2000). Punctuated equilibrium comes of age. In H. Gee (Ed.), Shaking the Tree: Readings form Nature in the history of life (pp. 17-31). Chicago: University of Chicago Press.
* When writing 'The Nature of the Chemical Concept' I was discussing the idea of natural kinds in chemistry (for example, 'potassium' has a better claim to refer to a natural kind than 'acid'), and the limitations of the notion of a natural kind. An example that I assumed would be familiar to readers was that of species. Species used to be considered different natural kinds each with their own essence, that were, largely at least, found distinct in nature:
Species as Natural Kinds? A Warning from Biology
"People, not just scientists, tend to naturally (sic, automatically) notice kinds in nature: for example, kinds of mineral, kinds of meteorological conditions (e.g., types of clouds), and perhaps most obviously, kinds of living thing…. When children, we all readily notice and learn that the world contains different kind of living things. There are birds and horses and dogs and fish and so forth. We come to recognise levels of classification without difficulty: this animal is a dog, and also a Labrador; this creature is both a sparrow and a bird. Later, when we study science in school we find that such distinctions are made formally by scientists, although not always in ways that entirely fit with informal everyday use… so mushrooms should not be considered plants, for example.
More advanced study might lead us to realise that the recognition of species and other higher-level taxa is not so straightforward. When I was at school, it was considered that the dinosaurs, the 'terrible lizards', as a group became extinct around 66 million years ago at the time of the formation of the Cretaceous-Paleogene (aka KT, Cretaceous-Tertiary) boundary, but since then 'lizard' has become a questionable category of natural kind, whilst many biologists now claim that birds are technically extant (rather than extinct) dinosaurs.
Having learnt that the main orders of vertebrates were fish, amphibians, reptiles, birds, and mammals, it appears that not only might birds be considered reptiles, but that reptiles are by some biological criteria not actually an essential kind (that is a kind with a particular essence). Even fish are not exempt. Leaving aside the tendency of the term fish to sometimes be used in a vernacular sense of sea creature (to include whales and 'shell-fish' for example), it seems that by some criteria fish do not share a particular essence as a group, as some fish are more closely related to members of other groups than they are to some other fish…. Guinea pigs are no longer seen as members of the mammalian group of rodents. In addition, these are just some examples from the vertebrates, among the most familiar groups of animals to most people….
Modern scientific thinking, post-Darwin, suggests that there are no absolute distinctions between species. Darwin himself thought he had done biology a service in offering the perspective on the biota suggested by his theory of natural selection. Descent of different groups from common ancestors, should (Darwin thought) have brought an end the interminable wrangling about whether particular groups were 'really' different species or actually varieties of the same species. For Darwin, understanding the origin of species suggested there could be no absolute distinct essence of any particular biological grouping such that there would always be an absolute distinction between specimens of one species and another"
Taber, 2019: 121-123
In writing about how the shift between species was a gradual process I went into the ideas about how over a long period of time the number of generations separating two individuals becomes ambiguous and how most of our ancestors must appear multiple times on our 'tree' of descent (which also means that if you go back far enough, most of those alive then, who have offspring alive today, are probably shared ancestors of most of us). However, this was getting somewhat peripheral to my key point about species and natural kinds. So I excised that material, thinking I might find another use for it. That text is reproduced above.
All images from '
