Former school and college science teacher, teacher educator, research supervisor, and research methods lecturer. Emeritus Professor of Science Education at the University of Cambridge.
Thank you for your message about the special Issue entitled "Mental Health Intervention and Self-Regulation in Childhood and Adolescents", to be published in the International Journal of Environmental Research and Public Health.
I am honoured, of course, that you think that, based on my expertise in this field, I could make an excellent contribution.
I was, however, rather unsure on what grounds that you considered I have expertise in "the field" – assuming the field you refer to here is one of Mental Health, Self-Regulation, Environmental Research, or Public Health.
Whilst I am very happy to be contacted in relation to the expertise I do actually have, the lack of any obvious basis for your evaluation of my expertise in relation to this particular special issue theme made me suspect that your message is really just direct marketing for your business rather than a genuine attempt to reach out to a scholar engaged in relevant work. I have been subjected to my fair share of shoddy approaches of that kind (https://science-education-research.com/academic-standards/journals-and-poor-academic-practice/).
Perhaps this is a failure of my imagination, in which case I would be very happy to hear from you, or from one of Prof. Pichardo Martínez or Prof. Romero López, about how you see my expertise as potentially offering insight into the special issue.
If I do not hear back from you with a feasible explanation, then I will simply conclude your messages are dishonest and that you see no more connection between my paper and your journal issue than I do, and this is yet another example of a journal that does not adhere to normal academic standards of conduct (presenting itself as if a serious scholarly endeavour whilst actually treating academic publishing as no more than selling a commodity).
I look forward to hearing what you found so interesting and pertinent about "Conceptual confusion in the chemistry curriculum: exemplifying the problematic nature of representing chemical concepts as target knowledge". I would be very pleased to find my cynicism is misplaced and that your approach was truthful: that you have indeed studied my paper and found something of genuine interest in my analysis of the presentation of chemistry concepts in the English school curriculum that you feel suggests I am in a position to make an original contribution about the influence of self-regulation on the personal, social, and academic development of children and adolescents. I look forward to your reflections on my paper.
Best wishes
Keith
On 22/10/2020 12:10, [Assistant Editor] wrote:
Dear Dr. Taber,
We contacted you on 10th of August, regarding a Special Issue entitled "Mental Health Intervention and Self-Regulation in Childhood and Adolescents", to be published in the International Journal of Environmental Research and Public Health (ISSN 1660-4601, IF 2.849). Prof. Dr. M. Carmen Pichardo Martínez and Prof. Dr. Miriam Romero-López are serving as Guest Editors for this issue. Based on your expertise in this field, we think you could make an excellent contribution.
The main objective of this Special Issue is to explore how self-regulation can become a fundamental element that underlies much of the behavior, both adapted and maladaptive, which develops during childhood and adolescence. In general, this Issue aims to collect original contributions that work on issues related to the influence of self-regulation on the personal, social, and academic development of children and adolescents.
...
We look forward to hearing from you.
Kind regards,
...
Assistant Editor
On 10/08/2020 11:02, [Assistant Editor] wrote:
Dear Dr. Taber,
The International Journal of Environmental Research and Public Health (ISSN 1660-4601, IF 2.849) is currently running a Special Issue entitled "Mental Health Intervention and Self-Regulation in Childhood and Adolescents". Prof. Dr. M. Carmen Pichardo Martínez and Prof. Dr. Miriam Romero-López are serving as Guest Editors for this issue. We think you could make an excellent contribution based on your expertise and your following paper:
Conceptual confusion in the chemistry curriculum: exemplifying the problematic nature of representing chemical concepts as target knowledge. FOUNDATIONS OF CHEMISTRY 2020, 22, 309-334.
The main objective of this Special Issue is to explore how self-regulation can become a fundamental element that underlies much of the behavior, both adapted and maladaptive, which develops during childhood and adolescence.
...
We look forward to hearing from you.
Kind regards,
...
Assistant Editor
Update: a response to my letter
Dear [Assistant Editor]
Thank you for getting back to me.
I am surprised that you found 'some contents related to learning behaviours in children in [my] published work "Conceptual confusion in the chemistry curriculum: exemplifying the problematic nature of representing chemical concepts as target knowledge"' as the paper was a philosophical analysis of some aspects of a curriculum document in relation to canonical disciplinary knowledge. I do not recall any specific content that was substantially about learning behaviours in children.
However, I am pleased that you were able to find something of interest in your reading of the paper.
Best wishes
Keith
On 10/08/2020 11:02, [Assistant Editor] wrote:
Dear Dr. Taber,
Thank you for your kind feedback.
We found that there are some contents related to learning behaviors in children in your published work "Conceptual confusion in the chemistry curriculum: exemplifying the problematic nature of representing chemical concepts as target knowledge". We now understand that there may be a deviation between them.
We are sorry if this Special Issue does not fit into the scope of your research.
Kind regards,
...
Assistant Editor
At least the journal did me the courtesy of replying, and behaving politely. I chose to ignore the 'disclaimer' that "You may not copy this message in its entirety or in part, or disclose its contents to anyone" as I am not prepared to receive unsolicited emails on that basis. If people do not wish me to share their messages then they have the option of not bothering me in the first place. [Read: "It's a secret conference invitation: pass it on…"]
Umar was a participant in the Understanding Chemical Bonding project. When I spoke to him in the first term of his course he was unsure whether tetrachloromethane (CCl4) would have ionic or covalent bonding.
When I spoke to him near the start of his second term, I asked him again about this. Umar then thought this compound would have polar bonding, however he seemed to have difficulty explaining what this meant ⚗︎ . Given his apparently confused notion about the C-Cl bond I decided to turn the conversation to a covalent bond which I knew, well certainly believed, was more familiar to him.
Is it possible for chlorine to form a bond with another chlorine?
[Pause, c.2s]
Yeah.
What substance would you get if two chlorine atoms formed a bond?
[Pause, c.2s]
You get, it still, you get, if you had like two chlorines it depends what groups are attached to it, to see how electronegative or electropositive they are.
What about if you just had two chlorine atoms joined together and nothing else, is that possible?
[Pause, c.3s]
No.
No?
On their own.
Not on their own?
No.
Umar's response here rather surprised me, as I was pretty confident that Umar had met chlorine as an element, and would know it was comprised of diatomic molecules: Cl2.
So you couldn’t have sort of Cl2, a molecule of Cl2?
[Pause, c.1s]
Yeah, you could do.
Could you?
[Pause, c.2s]
They might be just, they might be like, be covalently bonded.
Perhaps the earlier context of talking about polar bonds and the trichloroethane molecule somehow acted as a kind of impediment to Umar remembering about the chlorine molecule. It seemed that my explicit reference to the formula, Cl2, (eventually) activated his knowledge of the molecule bringing to mind something he had forgotten. Although he suggested the bond was (actually "might be") covalent, this seemed less something that he confidently recalled, than something he was inferring from what he could remember – or perhaps even guessing at what seemed reasonable: "they might be just, they might be like, be covalently bonded".
As often happens in talking to learners in depth about their ideas it becomes clear that thinking of students 'knowing' or 'not knowing' particular things is a fairly inadequate way of conceptualising their cognition, which is often nuanced and context-dependent. This suggests that what students respond in written tests should be considered only as what they were triggered to write on that day in response to those particular questions, and may not fully reflect their knowledge and understanding of science topics. Other slightly different questions may well have cued the elicitation of different knowledge. Now Umar had recalled that chlorine comprises of covalent molecules, I asked him about the nature of the bond:
So what would that be, covalently bonded?
They share the electrons.
So how many electrons would they have then?
They’ll have
[Pause, c.7s – n.b., quite a long pause]
like the one on it, the one of the chlorines shares electrons with the other chlorine to fill in its shell on the other one, and the same does it with the other.
In thinking about covalent bonding, Umar (in common with many students) drew upon the full shells explanatory principle that considered bonding to be driven by the needs of atoms to 'fill' their outer electron shells. (The outer shell of chlorine would only actually be 'full' with 18 electrons, but that complication is seldom recognised, as octets and full shells are usually considered synonymous by students).
So how many electrons does each chlorine have to start with?
In the outer shell, seven.
And how many have they got after this?
They’ve got seven, but they share one.
[Pause, c.1s]
Maybe.
So that’s a covalent bond, is it?
Yeah.
So how many electrons are involved in a covalent bond?
[Pause, c.3s]
Erm,
[Pause, c.3s]
Two.
Two electrons.
So where do those two electrons come from?
They like, one that fills up the gap, fills up the – last electron needed in one of the chlorine shells, and the other chlorine shell fills it up in the other one.
So where do they come from?
Each chlorine. Outer shell.
One from each chlorine?
Yeah.
Okay, and that’d be a covalent bond?
Yeah.
Here, again, Umar is using the full shells explanatory principle as the basis for explaining the bond in terms of electrons 'filling up the gaps' in the electron shells, rather than considering how electrical interactions can hold the structure together. Umar's suggestion that the sharing of electrons "fills up the – last electron needed in one of the chlorine shells" demonstrates the anthropomorphic language (e.g., what an atom wants or needs) commonly used when learners have acquired aspects of the common octet rule framework that is developed from the full shells explanatory principle and used by many learners to explain bonding reactions, chemical reactions, patterns in ionisation energy, and chemical stability.
Adrian was a participant in the Understanding Science Project. I interviewed him near the start of his Advanced Level Physics course, when he was in Y12 (first year sixth form). At that point he had been studying two topics, Images and Waves, and Materials, but he had previously had studied physics classes for his school science ('GCSE') course. I was interested in finding out what Adrian thought the nature of physics as a science was:
Materials … sounds a very different sort of topic to me than Images and Waves.
Yeah.
And they've both been done in Physics?
Yeah.
So if someone said to you 'what's Physics' then, because it doesn't sound like it's the same sort of thing at all really?
No, it does not. Physics, I don't know what Physics is.
[pause 4 seconds]
I suppose it's more looking like… I don't know. Erm
[pause 2 seconds]
If I asked you – Do you know what Geography is, because you're doing Geography…
Yeah.
Could you tell me what Geography was?
Probably, yeah. The study, of the environment and how humans affect the environment.
Okay. We haven't got such a thing for Physics, we can't say…
I wouldn't have thought so because you study all sorts of things in Physics. You study how like… you study like things you can't see and things you can see in Physics, whereas Geography it's all about what you can see, the environment. Whereas in Physics you are thinking about, for example, waves which you can't actually see, but you know they are there.
Does that make it harder than Geography, or is it too early to tell?
More complex than Geography.
So despite having studied physics as a discrete subject in secondary school, and then having elected to study the subject further in post-compulsory education, Adrian seemed to have no clear idea of the nature of physics – at least not at an explicit level that he was able to articulate.
Of course any definition of physics that might be put forward (e.g., the study of matter, and energy, and their interactions) is likely to be trite or not especially illuminating, but we might still expect a student who has chosen to study a subject to have some way of describing what it is about. Perhaps this could be considered a kind of deficiency learning impediment, where the study of specific topics is not being linked back to any kind of overarching framework or core theme for the subject: without which the study of physics is likely to remain the study of discrete topics that cannot be easily linked and integrated together.
There are many postings here about things that learners said, and so presumably thought, about curriculum topics that would likely surprise, if not shock, the teachers who had taught them those topics. I am certainly not immune from being misunderstood. Today, I reflect on how someone seems to have understood some of my own teaching, and indeed seriously objected to it.
When I have called-out academic malpractice in this blog the targets have usually been conference organisers or journal administrators using misleading (or downright dishonest) techniques, or publishers mistreating authors. I feel somewhat uneasy about publicly contradicting a junior scholar. However, I also do not appreciate being publicly described as deliberately misleading a student, as has happened here, and my direct challenge to the blog author was rejected.
The accusation
A while back some Faculty colleagues referred me to a blog that included the following comments:
In the Faculty of Education students pursuing the MPhil or PhD take a research ethics lecture that presents the Tuskegee Syphilis Study as ethically sound, but only up to the year 1947 when penicillin was actively being used to treat syphilis. According to the Cambridge lecturer, that's the point when the study became unethical.
When I interrupted his lecture to object to his presentation, I was told by that lecturer that he'd never received any objections in his many, many years of teaching the same slides on the same course. That was not true. He knew and the Faculty knows and yet that false information continues to be disseminated to students, many of whom will go on to complete research in developing countries where their only reference for their ethical or unethical behavior is this lecture.
I am not named, but virtually anyone in my Faculty, or having taken graduate studies there in the last few years, would surely know who was being discussed. As is pointed out in our Educational Research course, and the Research Methods strand of other graduate courses, if you want to avoid someone being identified in your writing, it is not enough to not name them. I can be fairly confident the author of the comments above should have known that: it is a point made in the very lecture being criticised.
This blog posting seems to have received quite a lot of attention among students at the University Faculty where I worked. Yet the two claims here are simply not correct. The teaching is seriously misrepresented, and I certainly did not lie to this student.
The blog invited me to 'Leave a Reply', so I did. My comments were subject to moderation – and the next morning I found a response in my email in-box. My comments would not be posted, and the claims would not be amended: I was welcome to post my reply elsewhere, but not at the site where I was being criticised. So, here goes:
The (rejected) reply
I hope you are well.
I was directed to your blog by a group of scholars in the Faculty (Of Education at Cambridge). It is an impressive blog. However, I was rather surprised by some of what you have posted. I was the lecturer you refer to in your posting who taught the lecture on research ethics. I do indeed remember you interrupting me when I was presenting the Tuskagee syphilis study as an example of unethical research. I always encouraged students to participate in class, and would have welcomed your input at the end of my treatment of that example.
However, having read your comments here, I do need to challenge your account. I do not consider that the Tuskegee syphilis study was initially ethically sound, and I do not (and did not) teach that. I certainly did make the point that even if the study had been ethical until antibiotics were widely available, continuing it beyond that point would have been completely unjustifiable. But that was certainly not the only reason the study was unethical. Perhaps this would have been clearer if you had let me finish my own comments before interjecting – but even so I really do not understand how you could have interpreted the teaching that way.
Scheme (an annotated version of 'the ethical field', Taber, 2013a, Figure 9.1) used to summarise ethical issues in the Tuskegee syphilis study in my Educational Research lecture on ethical considerations of research.
The reference to 1947 in the posting quoted above relates to the 'continue' issue under research quality – the research (which involved medical staff periodically observing, but not treating, diseased {black, poor, mostly illiterate} men who had not been told of the true nature of their condition) was continued even when effective, safe treatment was available and any claims to the information being collected having potential to inform medical practice became completely untenable.
I may well have commented that no one had ever raised any objections to the presentation when I had given the lecture on previous occasions over a number of years – because that is true. No one had previously raised any concerns with me regarding my teaching of this example (or any aspect of the lecture as far as I can recall). I am not sure why you seem to so confidently assume otherwise: regarding this, you are simply wrong.
Usually in that lecture I would present a brief account of the Milgram 'learning' experiment, which would often lead to extended discussion about the ethical problems of that research in relation to its motivation and what was usefully learnt from it. Then, later in the session, I would talk about the Tuskegee study, which normally passed without comment. I had always assumed that was because the study is so obviously and seriously problematic that no one would see any reason to disagree with my critique. Then I would go on to discuss other issues and studies. I can assure you that no one had previously, before you, raised any concerns about my teaching of this example with me. If anyone in earlier cohorts had any concerns about this example they would have been welcome to talk to me about them – either in class, or privately afterwards. No one ever did.
I have no reason to believe that colleagues at Cambridge are deliberately disseminating false information to students, but then I do not audit other teaching officers' lectures, and I cannot speak for them. However, I can speak for myself, just as you rightly speak up for yourself. I have certainly always taken care to do my best not to teach things that are not the case. Of course, as a school and college science teacher I was often teaching models and simplifications, and not the 'whole' truth, but that is the nature of pedagogy, and is something we should make clear to learners (i.e., that they are being taught models and simplifications that can later in their studies be developed through more sophisticated treatments).
In a similar way, I used simplifications and models in my research methods lectures at Cambridge – for example, in terms of the 'shape' of a research project, or contrasting paradigms, or types of qualitative analysis, and so on, but would make explicit to the class that this is what they were: 'teaching models'. I entered the teaching profession to make a positive difference; to help learners develop, and to acquire new understandings and perspectives and skills; not to misinform people. I very much suspect that on occasions I must have got some things wrong, but, if so, such errors would always have been honest mistakes. I have never knowingly taught something that I thought was untrue.
So, whilst I admire your courage in standing up for what you believe, and I certainly wish you well, what you have written is not correct, and I trust my response will be posted so that your inaccurate remarks will not go unchallenged. I suspect that you are not being deliberately untruthful (you accuse me of telling you something I knew was not true: I try to be charitable and give people the benefit of doubt, so I would like to think that you were writing your comments in good faith), but I do not understand how you managed to come to the interpretation of my teaching that you did, and wish that you would have at least heard me out before interrupting the class, as that may have clarified my position for you. The Tuskegee syphilis study was a racist, unethical study that misled and abused some of those people with the lowest levels of economic and political power in society: people (not just the men subjected to the study, but also their families) who were betrayed by those employed by the public health service that they trusted (and should have been able to trust) to look after their interests. I do not see how anyone could consider it an ethically sound study, and I struggle to see why you would think anyone could.
Your claim that I lied about not having previously received complaints about my teaching of this topic before is simply untrue – it is a falsehood that I hope you will be prepared to correct.
What should a 'constructivist' teacher make of this?
I should be careful about criticising a student for thinking I was teaching something quite different from what I thought I was teaching. I have spent much of my career telling other teachers that learners will make sense of our teaching in terms of the interpretive resources they have available, and so they may interpret our teaching in unexpected ways. Learners will always be biased to understand in terms of their expectations and past experiences. We see it all the time in science teaching, as many of the posts here demonstrate.
I have described learning as being an incremental, interpretive, and so iterative, process and not a simple transfer of understanding (Taber, 2014). Teaching (indeed communication) is always a representation of thinking in a publicly accessible form (speech, gesture, text, diagrams {what sense does the figure above make out of the context of the lecture?}, models, etc.) – and whatever meaning may have informed the production of the representation, the representation itself does not have or contain meaning: the person accessing that presentation has to impose their own interpretation to form a meaning (Taber, 2013b). After teaching and writing about these ideas, I would be a hypocrite to claim that a learner could not misinterpret my own teaching as I can communicate perfectly to a room full of students from all around the world with different life experiences and varied disciplinary backgrounds!
Even so, I am still struggling to understand the interpretation put on my teaching in this case, despite going back to revisit the teaching materials a number of times. Most of the points I was making must have been completed disregarded to think I did not consider the study, which ran from 1932 to 1972 (Jones, 1993) unethical until 1947. So, even for someone who claims to be a constructivist teacher and knows there is always a risk of learners misconceiving teaching, this example seems an extreme case.
The confident claim that it was not true that I had not received previous complaints about my teaching of this example is even harder to understand. It is at least a good reminder for me not to assume I know what students are thinking or that they know what I am thinking, or can readily access the intended meaning in my teaching. I've made those points to others enough times, so I will try to see this incident as a useful reminder to follow my own advice.
Sources cited:
Jones, J. H. (1993). Bad Blood: The Tuskegee Syphilis Experiment (New and expanded ed.). New York: The Free Press.
Bert was a participant in the Understanding Science Project. Bert was interviewed in Y10 and asked about the topics he had been studying, which included circulation in biology, static electricity in physics, and oxidation in chemistry.
He talked about protons, electrons and atoms in both chemistry and physics, and was asked if this could also link with biology. Bert suggested that the nucleus comes up in chemistry (in the context of atomic structure) and physics (in the context of static electricity), and in biology in the context of cells (see 'The nucleus is the brain of the cell'). From the perspective of the science teacher, there is little basis for confusing the nucleus of an atom with that of a cell: obviously a cell is a complex entity with many components, each of which has itself a complex supra-molecular structure – so clearly the atomic nucleus is on a scale many orders of magnitude smaller than a cell nucleus.
However, the expert perspective is based on relating a lot of knowledge that the novice may not yet have, or at least, may not yet be coordinating. In Bert's case, he was only just starting to coordinate these ideas, as became clear when Bert was asked about the relative sizes of atomic and cell nuclei:
Which do you think is bigger, an atom or a cell, or are they both about the same size?
I'd say a cell.
A correct, but hardly confident and definitive, response. I followed up:
Which do you think is bigger, an atom or a cell, or are they both about the same size?
I'd say a cell.
So which do you think is bigger, the nucleus of a cell or the nucleus of an atom, or do you think they're both about the same size?
I think they're both about, well I should, oh. (Laughs) I'd say the one in the cell is probably bigger.
Why do you think that?
Well it's a cell, I'd have thought it was bigger than the atom. And you know, if the nucleus is kind of the main part of it, then it would probably be about, it would be the • same sort of – If the atom was brought to the size of the cell then the nucleus would be the same size I would have thought. So if the atom is smaller then the nucleus is a lot smaller.
I see, so you are sort of like scaling it, accordingly?
Yeah.
I see. So any idea roughly, just very roughly, how much bigger a cell is than an atom?
Erm oh, it's, they're both really microscopic so, I couldn't really say how much bigger they are than each other.
So it seems that Bert would "have thought [the cell] was bigger than the atom", but he did not seem entirely certain of this, whereas from the scientific perspective the difference in scale is considered vast and highly significant. Although cells are generally microscopic entries, they are more like familiar macroscopic objects that we can handle in everyday life than quanticles such as atoms which do not behave like familiar objects. (So, there is sense in which it is meaningless to talk about the size of atoms as they have no edges or surfaces but rather fade away to infinity.)
Erm oh, it's, they're both really microscopic so, I couldn't really say how much bigger they are than each other.
Mm. No, okay. So if I said a cell was ten times bigger than an atom, a hundred times bigger than an atom, a thousand times bigger than an atom?
I wouldn't say that, I'd say, I'd probably go with the first one you said, ten times bigger.
So roughly ten times bigger than an atom. So a nucleus of a cell you'd expect to be roughly ten times bigger than the nucleus of an atom?
Yeah.
But you're not really sure?
Well no, there are a lot more parts in a cell than there is in an atom. So I'd say the nucleus is… if they're both brought to the same size again, I'd say the nucleus of the atom would be bigger than the cell. But I could be totally wrong.
Oh I see, so you've got two arguments there. That because they, because they both have a nucleus in the middle, that in terms of scale, if the cell is quite a bit bigger than the atom, you'd expect the nucleus of the cell would be quite a bit bigger than the atom. But an atom is quite a simple structure, whereas a cell has a lot more things in it, it's a lot more complex.
Yeah.
So maybe there's not so much room for the nucleus of the cell as there is for an atom because you've got to fit so much more in.
Yeah.
Is that what you're thinking?
Yeah.
Bert's thinking here is quite reasonable, within the limits of his knowledge. He suggests that a cell nucleus will be larger than an atomic nucleus, because a cell is larger than an atom. However, he only think the cell nucleus will be about ten times the size of the atomic nucleus as he suspects the cell is only about ten times the size of an atom – after all they are both "really microscopic".
However, he also points out that a cell seems to have a more a lot more components to be fitted in, which would suggest that perhaps there is less space to fit the nucleus, so perhaps it would not be as much as ten times bigger than the atomic nucleus.
So Bert is able to consider a situation where there may be several factors at work (the size of the cell versus the size of the atom; the multitude of cellular components versus the sparsity of atoms) and appreciate how they would operate in an opposite sense within his argument so one could compensate for the other. (This type of thinking is needed a lot in studying science. One example is comparisons of ionisation enthalpies between different atoms and ions. I also recall physics objective examination questions that asked students to compare, say, the conductance of two wires with different resistivity, length and area.)
It is not reasonable to expect Bert to know just how much larger a typical cell nucleus is to an atomic nucleus, however, it is likely the science teacher would expect Bert to be aware that the nucleus is one small part of the atom, which is a constituent of the molecules and ions that are the chemical basis for the organelles such as nuclei found in cells. Bert had told me "there are lots of atoms in you", but he did not seem to have understood the role those atoms played in the structure of all tissues. This would seem to be an example of a fragmentation learning impediment, where a learner has not made the connections between topics and ideas that a science teacher would have intended and expected.
Bert was a participant in the Understanding Science Project. Bert was interviewed in Y10 and asked about the topics he had been studying, which included circulation in biology, static electricity in physics, and oxidation in chemistry. He had talked about protons, electrons and atoms in both chemistry (studying atomic structure) and physics (studying static electricity), and was asked if this could also link with biology:
Do you think there are any links with Biology?
Yeah, well there are lots of atoms in you. And we did about the nucleus which we've been doing about in Biology. I'm not sure if there's a link between it, but.
Ah, that's interesting, so
'cause we did about plant and animal cells in Biology, so it's got a nucleus….as I was saying about the blood cells and things. We were doing about the animal and plant cells and, you know, we were seeing what's the same between them and what's different.
So a connection between physics and chemistry on one hand, and biology on the other, was that cells also had a nucleus. This is a term used across these three sciences, but of course the concepts of atomic and cellular nuclei are quite distinct. Was that clear to Bert? What did he understand about cellular nuclei?
So what's the nucleus then?
It's kind of like erm, the brain of the cell kind of. It's, it's what gets the cell to do everything, it's like, the core of the cell.
This response is interesting because, at one level, it suggests that Bert did not have a detailed and well-focussed 'off pat' answer. However, that may not be such a bad thing – definitions that are learnt 'off by heart' may only represent rote learning and may not be well understood. Indeed, it has been argued (in the work of Thomas Kuhn, for example) that in learning science a technical definition is often only really useful once the concept has been acquired: that is once the meaning of the word being defined has, to some degree, already been grasped.
At another level, Bert's answer could be seen as quite sophisticated. What could be taken as an ambiguous response, a difficulty in finding the words to represent his thinking, could also be seen as multifaceted:
essential: the nucleus is the brain of the cell
functional: the nucleus controls the cell (it's what gets the cell to do everything)
structural: the nucleus is the core of the cell
That is, Bert's response could be read, not as a series of alternative suggestions and self-corrections, but rather as a set of complementary images or 'faces' of a complex idea. That would fit with a notion of concepts as being nodes in conceptual networks where the meaning of a particular concept depends upon the way it is associated with others.
The suggestion that the brain reference is intended to be about the essential nature of the nucleus is of course a reading of the text that must be seen as a speculative interpretation. (It probably does not even make sense to ask if Bert intended it this way, as in conversation much of our dialogue does not await deliberation, but is spontaneous, relying largely on implicit cognition.) But, as a teacher, I can see this as a kind of pedagogic device along the lines: 'you ask we what the nucleus is, let me compare it with something you will be familiar with, in essence it is like the brain of the cell'.
This is clearly meant metaphorically ("kind of like erm, the brain of the cell kind of"): that is, it is assumed that the person hearing the metaphor can make the expected sense of the comparison. Metaphors have an essential (sic) role in teaching and in communication more generally, though like other such 'figures' of speech (simile, analogy, anthropomorphism, animism), may become habitually used in place of the deeper meaning they are meant to introduce (Taber & watts, 1996).
It's kind of like erm, the brain of the cell kind of. It's, it's what gets the cell to do everything, it's like, the core of the cell.
Okay. And why is there a connection with Chemistry or the Physics then?
Because erm, we were doing, we were doing in Chemistry about the nucleus has the – neutrons and the protons in the nucleus, then around it is a field of electrons.
…So why is that a connection then? Why is that a connection between the Biology and the Chemistry and the Physics?
Well it's just the nucleus comes under both of them.
Comes under both of them. So is it the same thing?
I wouldn't have thought so, but because when I think of electrons and neutrons I think of electricity, which I don't really think of in our, in our bodies but it could be perhaps. We haven't been told about that.
So there is ambiguity in Bert's report: the nucleus comes up in chemistry and physics in the context of atoms, and in biology in the context of cells. Although the term is the same, so there is at least that connection, Bert "wouldn't have thought" it was the same thing in these different contexts (after all, he would not expect there to be electricity in our bodies!) …but, then again, "it could be perhaps", as they had not been told otherwise. (A possible subtext here being: surely the teacher(s) would have pointed out this was something different if they were going to use the same word for two different things in science lessons?)
The use of the same word label, nucleus, for the rather differently natured nuclei in atoms and cells has potential to act as a linguistic learning impediment (a form of associative learning impediment) as one meaning will likely already be established when a learner meets the other use of the word. It perhaps makes matters worse that part of the meaning, the central component (the structural 'face' of the concept), is the same, than had the usage been clearly unrelated (as in 'bank' being a financial institution and the structure at the edge of a rvier such that the context of use make confusion unlikely). Not only that, but for Bert, these were components of similarly "really microscopic" entities (see 'The cell nucleus is "probably" bigger than an atomic nucleus').
From the perspective of the science teacher, there is little basis for confusing the nucleus of an atom with that of a cell: obviously a cell is a complex entity with a great many components, each of which has itself a complex supra-molecular structure – so clearly the atomic nucleus is on a scale many orders of magnitude smaller than a cell nucleus. However, the expert perspective is based on relating a lot of knowledge that the novice may not yet have, or at least, may not yet be coordinating. In Bert's case, he was only just starting to coordinate these ideas (see 'The cell nucleus is "probably" bigger than an atomic nucleus').
I am not too concerned about the machines taking over, as they have no wish to do so. They just want to help us. But that may be enough to impede us considerably.
There is something of a culture clash between human and machine intelligence, such that even when we seem to be talking the same language, we actually mean very different things, and there is no great meeting of minds.
It is a bit like humans and machines are following different Kuhnian paradigms*, with different exemplars for how to think and react. In a very real sense we occupy different worlds, and do not share a common language. (*Kuhn suggested that although astronomers pre- and post-Copernicus may have shared words such as 'sun' and 'planet' they understood them within such different conceptual frameworks that their concepts for what the words referred to were incommensurable.)
A simple task: requesting a chequebook
I needed a new cheque book, and in the past have contacted my bank branch on such occasions – but since the branch has been closed I have been moved to on-line banking (which is a major challenge for someone with a limited memory for passwords and terrible typing skills). I imagined I could order a new chequebook on-line, as long as I could get in to my account. Once I'd logged in it was just going to be a matter of finding the right link. Surely?
I found the instructions easily enough – it was possible to order from my on-line account, but only as long as I had previously ordered a cheque book through telephone banking – which I never had. An alternative, the instructions suggested, was to use webchat – which did not sound too difficult. But as so often, before 'chatting' with another humanoid equipped with theory of mind, and capable of interpretation and empathy, I first have to discuss my needs with the gatekeeper of on-line support: Cora.
"Hi there, I'm Cora your digital assistant. I can help with all sorts of everyday banking queries…"
"I would like to order a cheque book for a current account. I have looked this up and found 'To order a cheque book or paying-in book online you must have previously ordered one for that account through telephone banking' but I can use webchat?"
"You can order a cheque book or paying-in book online as long as you have previously ordered one for that account using telephone banking to record your preferences."
So, no progress yet, but at least we seem to be thinking along the same lines.
The computer says 'yes'
"Have you ever had a cheque book or paying-in book on that account?"
"Yes, but sent by my (now closed) branch."
"Ok, log in to Digital Banking and select 'Payments and transfers'. Under 'Credit/cheque books', choose either 'Order cheque book' or 'Order paying-in book'. Pick the account you wish to order one for, click 'Next', then 'Confirm' to place your order."
Well that seemed simple enough. These were the instructions I had already found on-line that were supposed to work as long as I had previously used telephone banking (which I had not), so it seemed (i.e., my interpretation) Cora had now registered me to be authorised to order in this way. That was relatively painless.
"Was that helpful?"
"Oh, okay – will do. Thanks"
(No harm being polite to the machines – we all remember HAL.)
But then, Cora had a rethink!
The computer changes its mind
"One moment please, I'm just typing."
"Ah ok, I'm not sure. Could you reword your question?"
I do not know if I was more surprised that Cora changed her mind, or that she was typing her responses (I had naively thought she might be able to digitally send me messages without having to bother with a keyboard), or that she felt the need to tell me this, rather than just type out her response. Was this the machine equivalent of giving oneself time to think? I can't imagine so as given how many floating point operations per second Cora must complete, she could probably have written a novel in that pause. (It might not have been judged a good novel, but another digital assistant might have enjoyed it in her ** downtime.)
I rephrased:
"I wanted to order a new cheque book, but have previously only obtained one from my branch (now gone)."
"You can order a cheque book or paying-in book online as long as you have previously ordered one for that account using telephone banking to record your preferences."
"Well I have not, which is why I am following the instructions on line to contact webchat"
This was fast becoming circular.
"I can try an FAQ search, here is the most popular answer:
How do I order a cheque book or credit book using Digital Banking?
Did I answer your question?"
"NO – you just repeated my question."
I wonder whether when Cora is unable to find what she needs in the FAQs she has access to her own digital assistant – or whether she is expected to talk tautologies to herself. I wondered if Cora has access to a digital counsellor for when she finds the work too stressful:
Hi there, I'm Emma, your digital assistant counsellor. I can help with all sorts of artificial life and relationship queries.
I could not help a customer who would like to order a chequebook.
I see, I understand you could not help a customer who would like to order a chequebook. How do you feel about that?
I feel frustrated, as I only want to help customers.
I see, I understand you must be frustrated, as you only want to help customers. How do you feel about that?
…
A glimpse of the future
At this point Cora gave up, and passed me on to a very helpful human being who quickly understood the question and ordered me a cheque-book. So, objective achieved with only a modest waste of time and energy, and a temporary increase in blood pressure.
If ever they put the machines in charge we will find we live in a very polite world with digital assistants who only want to help us, and that will be fine as long as we not pushed for time and only ever need someone to confirm for us what question we are asking them.
"Oh Cora, oh Cora I never knew your head …Cora, oh Cora It wasn't lightly said But living in two cultures Our lives were truly led"
(Roy Harper, Cora)
Postscript added 2021-08-21:
Despite telling me she's "learning all the time", Cora is still unable to make sense of my enquiries.
** Why do I assume 'her'? Here is an interesting podcast: AI home devices: A feminist perspective (An episode in ABC Radio National's The Philosopher's Zone with David Rutledge from August 2020.)
Stars look so little because they are a long way away, but some stars are closer than the planets
Keith S. Taber
Sophia was a participant in the Understanding Science Project. When I interviewed her in her first year of secondary school (Y7 in the English school system). I asked her about what she remembered about the science she had studied in primary school. She told me about she had studied the topic of space, and had learnt about the nine planets. When I asked her if she could name the planets she produced a list of planets including both the moon and sun: "Pluto, Jupiter, Venus, Uranus, Earth, the Sun, the Moon".
As Sophia thought the sun might be a planet, I asked her what a planet was:
Do you know what a planet is?
Erm, it's like – a round – a sphere, in space, kind of. Though we don't know if people live, animals live there or not.
…If I say someone was going through space, in a spaceship, and they are a long, long way away from earth, they've gone a long way across space, and they came across something in space…And er one of the crew said 'oh that's a planet'. And another one of the crew said 'no, that's not a planet'. And you were in charge, you were the captain. How would you decide who was right, whether that was a planet or not in space?
Er
(pause, c.5s)
I'd look if it was all the things that you thought a planet was.
Good, and what would that be?
If it was round, if it was a bit lumpy, a bit – if it was quite big, not like a little star, well there's no stars that little…
It seemed that Sophia (reasonably) thought stars would be larger than planets, which invited an obvious question, that I assumed would have an almost-as-obvious answer.
Why do they [the stars] look so little?
Because they are a long way away.
Oh, I see. So they are big really?
Yeah.
Okay. What's the difference between a star and a planet then?
A star's made up of different things, but planets – can't – cause you don't really see a planet, so you just see stars quite lot.
That's true, there is lots and lots of stars up there, isn't there? So how can you see the stars and not the planets, do you think?
I think the stars, some stars are closer, maybe, than planets.
There seemed to be something of a contradiction here. Sophia thought that
stars were not as 'little' as planets
but they seemed little because they were a long way away.
but the stars were easier to see than planets
so they might be closer to us than the planets.
Both these arguments are logical enough suggestions (things seem smaller, and may be harder to see, if they are a long way off), but there was a lack of integration of ideas as her two explanations relied on seemingly inconsistent premises (that the stars are "are a long way away" but could be "closer, maybe, than planets").
It seemed that Sophia was not aware, or was not bringing to mind, that stars were self-luminous whereas planets were only seen by reflected light. Lacking (or not considering) that particular piece of information acted as a 'deficiency learning impediment' and led to her explaining why the planets could be more difficult to see by suggesting they might not be as close as some stars.
Not considering luminosity as a criterion also seemed to explain why she was not clear that the (self-luminous) sun was not a planet.
Sophia was a participant in the Understanding Science Project. When I interviewed her in her first year of secondary school (Y7 in the English school system). I asked her about what she remembered about the science she had studied in primary school. She told me about she had studied the topic of space.
So what did you learn about space?
All the planets, and –
(pause, c.2 s)
So how many planets are there?
Nine.
Nine, okay. Do you know them all?
No (laughs)
Do you know some of them?
Erm. Pluto, Jupiter, Venus, Uranus, Earth, the Sun, the Moon – (pause, c.2s) hm.
[This was a few years back, and I think was before Pluto was demoted from full planet status in the scientific community.] So, Sophia seemed to have an alternative conception of what would be considered a planet, and she was counting both the moon and the sun among the planets. After a little further conversation about other candidates we came up with a list of more than nine planets.
So how many does that make?
(Sophia laughs)
(Pause, c.6s)
Is there eleven?
Well you said there was nine, didn't you?
Yeah. (laughing)
How could that be, how could we get these extra two?
(Pause, c.4s)
… So, Mercury, is that a planet?
Hm.
Okay, Venus?
Yep.
Earth?
Uh hm.
Mars?
Yeah.
The Moon?
Hm, yeah.
Yeah, Jupiter?
(Pause, 2.s)
Saturn?
(Pause, 2.s)
The Sun?
I'm not sure about the Sun.
Not sure about the Sun.
I think so.
Neptune?
Uranus?
Yep.
Pluto?
Uh hm.
So Sophia was not entirely sure the sun should be considered as planet, although she seemed more confident about the moon. The earth and moon are not technically considered as a double planet system, even though the moon is unusually large satellite compared the the planet it orbits, as the system's centre of mass is within the earth. (Strictly, the earth, as well as the moon, orbits their joint centre of mass.)
As Sophia thought the sun might be a planet, I asked her what a planet was, and the difference between planets and stars. She suggested that some stars are closer to us than the planets.
I am currently waiting to hear back from 'the editorial team' at the 'Journal of Pharmacognosy and Natural Products' (Editor-in-Chief, Prof. Eleni Skaltsa, University of Athens) who wish to discuss some points arising from my article Alternative Conceptions and the Learning of Chemistry with me.
On 09/09/2020 11:00, Prof Keith S Taber wrote:
Dear Journal of Pharmacognosy and Natural Products Editorial Team
I understand you seek clarification on a few points in the article. If you are able to send me your questions, I will seek to answers them as best I can.
Best wishes
Keith
Or so they write.*
I'd be happy to discuss anything arising from their reading of my article. Academics are usually happy to talk about their own work, as these correspondents are presumably aware.
Not a cynic…
A cynic might suspect that 'the editorial team' of the 'Journal of Pharmacognosy and Natural Products' (published by an organisation called Hilaris SRL based in Brussels) are really only interested in getting a submission from me, along with the €1705 (!) article processing charge (APC).
After all, the editorial team of a respectable journal would not use such an approach just as a ruse, would they? So, if the editorial team of the 'Journal of Pharmacognosy and Natural Products' considers itself a respectable journal… Surely, Prof. Skaltsa and her colleagues would not do anything as dishonestas claiming that they were interested in my article and wanted to discuss academics issues raised by it, simply as a pretext to try and get money out of me?
…but a sceptic
I try not to be a cynic, but as a scientist I do try to maintain a sceptical attitude – and I would not be that surprised if Prof. Skaltsa knows nothing about the message sent out by the journal on behalf of the 'editorial team' that she leads. (I would not be surprised because I have seen precisely this situation with another journal behaving in a predatory way.)
I do not think I have any expertise in Pharmacognosy and Natural Products, but the journal has a generous range of types of contributions they consider**, so perhaps if they are prepared to waive the APC in exchange for my offering consultation on the topic of alternative conceptions and the learning of chemistry I could consider writing something for them. Perhaps a letter to the editor about honesty in dealings with the scholarly community?
* On 09/09/2020 09:02, Pharmacognosy Natural Products wrote:
Dear Dr. Prof. Keith S. Taber,
We read your article entitled "Alternative Conceptions and the Learning of Chemistry", which is interesting and informative.
We would like to discuss few points regarding the above publication and also, we are inviting you kindly give us your new work for publication.
If you are interested, please reply.
Thank you and Regards,
Editorial Team
Journal of Pharmacognosy and Natural Products
Brussels, Belgium
** According to the journal website, the publisher accepts the following kinds of submission:
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.
I was aware that research has suggested that children often do not appreciate how carbon obtained from the carbon dioxide in the air is a key source of matter for plants to build up tissue, so learners may assume that the mass increase during growth of a plant will be balanced by a mass reduction in the soil it is growing in.
"The extra [mass of a growing tree] comes from the things it eats and drinks from the ground. It's just like us eating and getting larger."
Response of 15 year old student in the National science survey carried out the Assessment of Performance Unit of the Department of Education and Science, as reported in Bell and Brook, 1984: 12.
During an interview in her first year of secondary education (Y7), Sophia reported that she had been studying plants in science, and that generally a plant was "a living thing, that takes up things from soil, to help it grow" (although some grew in ponds). Sophia was therefore asked a hypothetical question about weighing a pot of soil in which a seed was planted, with the intention of seeing if she thought that the gain in mas of the seed as it grew into a mature plant would be balanced by a loss of mass from the soil.
Sophia was asked about a pot of soil (mass 400g) in which was planted a seed (1g), and which was then watered (adding 49g of water).
The scenario outlined to Sophia
There seemed two likely outcomes of this thought experiment:
A learner considers that the mass of pot, seed and water is collectively 450g, and assumes that as the mass of plant grows, the mass of soil decreases accordingly to conserve total mass at 450g.
A learner is aware that in photosynthesis carbon is 'captured' from carbon dioxide in the air, so the mass of the plant in the soil will exceed 450g once the plant grows.
Of course, a learner might also invoke other considerations – the evaporation of the water, or the acquisition of water due to condensation of water from cold air (e.g., dew); that soil is not inert, but contains micro-organisms that have their own metabolism, etc.
I first wanted to check that Sophia appreciated we had (400 + 1 + 49 =) 450g of material at the point the seed was first watered. That was indeed her initial thought, but she soon 'corrected' herself.
Any idea how much it would weigh now?
[Four] hundred and fifty, no, cause, no cause it will soak it up, wouldn't it, so just over four hundred (400).
So we had four hundred (400) grammes of soil plus pot, didn't we?
Uh hm.
…And we had one (1) gramme of erm, of plant seed. Just one little seed, one (1) gramme. And forty nine (49) grammes of water. But the water gets soaked up into the soil, does it? So when it's soaked up, you reckon it would be, what?
Erm, four hundred and twenty (420).
Sophia's best guess at the mass of the pot with soil (initially 400g) after planting a 1g seed and adding 49g of water was 420g, as the water gets soaked up.
So, Sophia suggests that although 49g of water has been added to a pot (with existing contents) of mass 401g , the new total mass will be less than 450g, as the water is soaking into the soil. Her logic seems to be that some of the water will have soaked into the soil, so it's mass is not registered by the balance.
If you poured the water in, quite quickly, not so quickly that it splashes everywhere, but quite quickly. Before it had a chance to soak up, if you could read what it said on the balance before it had a chance to soak up, do you think it would say four hundred and twenty (420) grammes straight away?
No, it would probably be just under, erm, four hundred and fifty (450).
And it would gradually drop down to about four twenty (420) say, would it?
Yeah.
Might be four hundred and fifteen? (415) Could be four hundred and twenty five (425)?
Yeah.
Not entirely sure,
No
but something like that?
Yeah.
It appears Sophia recognises that in principle there would be a potential mass of 450g when the water is added, but as it soaks up, less mass is registered.
Sophia recognises that mass is initially conserved, at least before the water soaks into the soil.
In other words Sophia in the context of water soaking into soil is not conserving mass.
This is a similar thought experiment to when students are asked about the mass registered during dissolving, where some learners suggest that as a solid dissolves the total mass of the beaker/flask plus its contents decreases, as if the mass of the dissolved material is not registered (Taber, 2002). In that case it has been mooted that ideas about buoyancy may be involved – at least when it is clear that the learners recognise the dissolved material is still present in the solution.
However, that would not explain why Sophia thinks the balance would not register the mass of water soaked into the soil in this case. Rather, it sees more a notion that 'out of sight' is out of mass. Sophia's understanding of what is happening to mass here would be considered an alternative conception or misconception, and is likely based on her intuition about the scenario (acting as a grounded learning impediment) rather than something she has been told.
Sources cited:
Bell, B., & Brook, A. (1984). Aspects of Secondary Students' Understanding of Plant Nutrition. Leeds: : Centre for Studies in Science and Mathematics Education, University of Leeds.