- Section I
- The zygote1 is an exception to the usual procedure whereby a new cell comes into existence from the division of an old cell, since it is formed from sperm & ovum.
- Textbooks claim that this is the beginning of a new human individual, thereby forgetting about identical twins2.
- These arise from the cleavage of the zygote3 into two cell-clusters before thirteen days’ gestation. There are still < 104 cells at this stage whereas the human adult has of the order of 1014 cells.
- If you are an identical twin, then if you were once a zygote4, then you and your twin were once jointly that zygote5.
- The zygote6 is alive, a human thing, a new beginning of human life and not a part of a human being.
- There is an objection to saying that the zygote7 is a human being “a whole new human entity”. This is because what we mean by this is a man (Mensch, homo, ἄνθρωπος) – a human (as English lacks the term). Anscombe’s "Twinning8" argument – we are to imagine twins9 B & C resulting from zygote10 A, with neither B nor C being identical to A11 – runs as follows, We have to choose one of:-
- A, not yet divided, was already two, so was already a pair of humans, B & C.
- A was just one human, but became two by another growing out of it.
- A was just one human, but became two by division as an amoeba does.
- A was neither a human, nor a pair of humans, but (only) a “whole human substantial entity”.
- Anscombe now considers these options:-
- Already two:
- There is no evidence for the first option in humans. She cites Prof. Jerome Lejeune12. It seems that in some species of armadillo the egg always splits into four – so twinning13 is genetically-imprinted and we could tell – from the moment of conception – that twinning14 is about to occur; but, there is no evidence of this in human beings.
- However, as this is an open questions, Anscombe notes that certain philosophical worries concerning the “odd logical status of the zygote15 – this human entity which is an individual substance, not part of one, and not a human16” would disappear were it to be proved true.
- Anscombe is “disposed to dismiss this (option) out of hand”, but admits it requires discussion.
- In the case of the amoeba, there’s no disputing that we start with one amoeba and end up with two.
- But, in the case of human twinning18, it’s precisely the point at issue whether we start off with a human.
- What account could we give of it becoming two humans?
- Neither of the two resulting zygotes19 can be identified as the (supposed) original human as they can’t both be so, as they are not identical to one another.
- We might say – she claims – that each had been20 the same human as the zygote21, and therefore the same human as the other – though they are not the same human now.
- But what happened to this original zygote22 – did it cease to be, like a parent amoeba?
- Anscombe repeats the assertion that the present non-identity of B and C does not prove that they were not once identical to A23 and hence to one another.
- Nor – she seems to say – does it prove that they may have been identical to A.
- Indeed, before A split – whether A be a zygote24 or an amoeba – neither B nor C existed25.
- Should we say that any cell – such as an amoeba – that divides does not cease to exist, but continues on as two rather than one – and continues to exist in (or as) its multitude of simultaneous descendants?
- She makes an analogy between Adam and the amoeba – we are sometimes said all to be Adam26; yet, Adam died, but the amoeba did not die.
- Anscombe sees a dis-analogy27 between – or at least rejects the analogy between – the case of the amoeba and the human zygote28:-
- Basically, the key difference is that by the time the zygote29 is multi-celled, there’s a distinction to be drawn between the cells and what they constitute30; but, this is not the case with the amoeba for which a single cell just is the amoeba.
- So, while neither the zygote31 nor the amoeba die32 (strictly-speaking) when division occurs – they both just cease to be – what continues on has a different connection to what went before in the two cases.
→ What follows amoeba division is more amoebas – a continuation of amoeba life.
→ What follows zygote33 division is two new humans (eventually, at least).
- So, while it’s true that the cells of the twins34 are descended from just one cell, the two new humans (thought of as such) are not.
- One cluster of cells persists as two clusters of cells – which are its descendants – but even if the zygote35 pre-division had been a human, it would not persist as two new humans.
- This seems to be Anscombe’s preferred option, but she has no more to say on it.
- Section II
- Can we say that I was once the sperm and egg that came to form the zygote36 from which I developed?
- The objection to this idea is that the sperm and egg were separate substances until they came to form one cell.
- Cells are not usually substances – only parts thereof. The reason Anscombe gives as proof is that of cell differentiation once division proceeds (a sufficient way). The purpose of this process is the production of a structured living organism organised to use the differentiated cells. The kind to which the organism belongs determines the differentiation, assuming it proceeds normally.
- Anscombe makes a couple of comments the relevance of which I’m uncertain, though presumably they are in support of the above “proof”:-
- Textbooks of genetics everywhere assume “the norms of health and reproduction of undefective specimens of a kind” guide research.
- In such books “syndromes” don’t apply to “normally or successfully operating physiques or powers”.
- So, if a zygote37 is not already a human, its development cannot be because of its membership of the species. It is that of the individuals from whence the gametes came, and also of the individual(s) into which it will develop if it does so normally.
- Anscombe draws a distinction between “a human substance” and “a human”.
- A zygote38 is the start of a new human substance.
- I was that zygote39.
- That zygote40 was the beginning of the human being that I am.
- If the human substance that I am did indeed begin with the zygote41, then it was possible for me to exist then without being a human. I was simply “something human”.
- She claims that one can become two42, but that two cannot become one43.
- Anscombe continues her “fusion” analogy by considering two lumps of clay44:-
- Two lumps of clay45 can become one; the one lump had been two, but became one by the two being pressed together leading to the removal of a boundary.
- But this isn’t the case when the sperm and egg become a zygote46. The zygote47 wasn’t previously two cells, by analogy with the once lump having previously been two lumps.
- The reason is that there is no substantial change in the case of the clay.
- But in the case of the zygote48, a new organism – with a new genetic makeup – comes into existence, ready become a new member or members of the species of its parents.
- The lives of the sperm and egg are over, replaced by the new life of a new individual – the zygote49.
- Anscombe claims that50 “life=existence”.
- In starting to live, the zygote51 has started to exist.
- Materially, it was the two former cells, but not so in form and existence.
- In form it is a new kind from its predecessors, which weren’t organisms just needing nutrition to grow into a certain pattern.
- In existence, its life (or its being alive52) is not their life.
- But, the division of the zygote53 into twins54 is – Anscombe claims – like the division of a lump of clay55 into two lumps:-
- The life is split in two only insofar as a living thing is split in two.
- But after the split we can’t say we have two animals.
- We can only say we have two materially distinct carriers of life (both of) which56 started with the formation of the zygote57.
Originally a lecture given to the RIP in 1982.
Footnote 11: Is this taken as obvious, a premise, or the conclusion?
Footnote 12: Footnote 16: This is option 4.
- Anscombe doesn’t spell this out.
- However, it’s easy to see why the problem disappears.
- If “budding” occurs, then the twin is logically distinct from its “parent”, from which it arises essentially by asexual reproduction.
- The “parent” zygote persists, but loses part of its matter which forms a new, numerically distinct, individual.
- It is thus a case of asymmetric fission.
Footnote 23: Footnote 25: This seems to ignore the possibility of perdurantism.
- How is this supposed to work?
- Maybe see the next footnote.
- What purpose does this doubtful analogy serve?
- Does she – or those who use this figure of speech – think there was a real Adam?
- Does this matter for her argument?
- I think I understand her argument, but have completely re-stated it.
- But, re-reading it, it may not be right.
- I’ll try to fix this after reviewing the entire paper.
- Anscombe has this as a conditional, but I think she accepts this statement as a major premise.
- If this is a correct interpretation, then her answer to the Essay’s title “Were you a zygote?” is “yes”.
- But she denies that I was then an individual human being (“a human”).
- This is fission, in this case twinning.
- But the point of contention is whether either fission-product can be identical to the pre-fission entity.
- Looking at the parallel with fusion, it looks as though she does believe this to be possible.
- So, she denies that fusion is possible.
- This seems a bit blunt, not to say a conceptual confusion, so this bald statement needs unpacking.
- As a Catholic, Anscombe can’t hold that “life” is a biological concept, since God (or Christ) is said to have life most abundantly.
- So, maybe she’s just saying that the aspect of life she has in mind is (the beginning of) existence.
- Again this is rather succinct.
- Does she mean that the three lives are numerically or qualitatively distinct?
- Both statements are likely true.
- Presumably it’s the “carrying of life” – rather than the life itself – that started with the zygote.
- Since, there was one life formed when the zygote was formed, and
- This one life was terminated when the two new lives of the twins took its place.
Text Colour Conventions (see disclaimer)
- Blue: Text by me; © Theo Todman, 2019
- Mauve: Text by correspondent(s) or other author(s); © the author(s)