Last time I touched on the problems Thomistic philosophy has with evolutionary theory’s lack of any way of dealing adequately with the concept of form (formal causation, in Aquinas-speak). I mentioned that Darwin was only able to introduce his theory on “The Origin of the Species” by spending many pages seeking to demonstrate that the concept of a species, meaning a class of “natural substances” sharing a single essential nature, was meaningless anyway. To all subsequent evolutionary theory, this philosophical nominalism has been axiomatic. If evolution is a constant flux of changeable characteristics, then there can be no real genera or species embodying tiger-ness, or hors-itude, or even, come to that, basic human nature.
That poses no apparent problems when we’re concentrating on comparing macro-evolutionary changes: a point mutation here, a gene duplication there, or even a symbiotic event like the incorporation of mitochondria seems to explain nicely how you stopped being a sponge or lanceolet. But the issue of form and of universals raises its head a little more in practical terms as we see that the overall pattern of the fossil record demonstrates sudden changes followed by stasis in forms: what is it that keeps the morphology stable over those millions of years of stasis … or more fundamentally, what exactly is being kept stable?
Population genetics shows that our genetic material is in a constant state of flux: your ancestral history can even be traced by the mutations of your genes. That can show why you’re not a chimp, but if most of your alleles are different even from your neolithic or mediaeval ancestors, what makes you both “human”? And where is the boundary? What’s stable if all the genes have changed?
Conveniently we can usually choose to ignore that question because all our confusingly close hominin ancestors are extinct. Nowadays, the widest genetic differences between ethnic groups are known to be no wider than those within them. Our topical “genealogical hypothesis” for Adam confirms the biblical statement that we are all from “one blood”, and that blood is well mixed within recent memory too. Nearly all “white” Americans carry typically “African” genes acquired within recent history, and I always remember my “black” patient who appeared in a TV documentary with her “white” twin sister. Any significance to ethnic differences reflects sociology, not genetics – which makes the new insistence on clear racial self-identities a “progressive” throwback to eugenic ignorance.
And yet – admirable as it may be to bury racism under a common humanity, actually the only materialist justification for saying there is a universal called “humanity”, rather than just a lot of similar organisms, is that we interbreed. But people interbred with Neanderthals and Denisovans too. And what happens when they start hybridizing genomes with extra-specific, or even synthetic, DNA?
I’m looking forward to J Scott Turner’s forthcoming book Purpose and Desire which, in part, follows Denis Noble is focusing our attention on the inability of current evolutionary theories to explain homeostasis. There is a “normal” state for an individual, a “form” which we seek to maintain, or to restore when it is disturbed. But there is homeostasis in the species too, despite the universals called species being non-existent in a Darwinian universe. I spent a career interpreting the results of medical histories, examinations and investigations – and it was all about comparing them to what I had learned to be “normal”. Without a theory of formal causation, there is no “normal”, even though we run our lives by it.
But it’s not enough to shrug and take homestasis, species, and so on for granted in practice whilst denying their reality in theory: there is actually a direct conflict between our theory of evolution, which says that living things can change indiscriminately, and our everyday experience, which says that living things strive in a thousand ways to stay true to what they are as individuals, and as members of what Aquinas considered to be the far more clearcut embodiment of form – their species, whose origin Darwin ostensibly explained but actually explained away.
Lack of any explanation of form hits closer to home, too. In a nostalgic mood yesterday I was looking back on the achievements and follies of my youth. As a teenager I acquired a piece of paper allowing me to drive a car – a little later a bigger bit of paper qualified me to practise medicine. But why are those entitlements still valid (the medical one isn’t, but only because I erased myself from the medical register on retirement to save money)?
My physical appearance has changed to the extent that I have to tell people who I am at college reunions. All kinds of bits are wearing out, and my views, knowledge and opinions have changed radically over the years. A majority of my cells have been replaced, and nearly all the actual molecules. So in what sense am I the same individual who gained a qualification way back? Or suppose I had a guilty secret and had murdered someone in my youth, and it came to light. Would the authorities be impressed by my saying I’m no longer the same person? That doesn’t get Nazi war criminals very far.
Well, you might point to my genome as being the constant factor. But my identical twin daughters have the same genome, and yet can’t pool either their qualifications or their criminal liabilities. But in any case, our genome isn’t constant. Not only does our gene-expression change radically through life, and differently in each cell type, by epigenetic modification, but our genome itself changes extensively over time, and not least in our brain cells, where our accountability might be thought most to reside.
Now, in practical terms it’s a non-problem. I know my past is my past, and you know your past is yours, because I know that I am me and you know that you are you. Anxiety-dreams about practising medicine persist despite most of my molecules having been replaced since I last practised, and if I had guilty nightmares about a murder I once committed, neither I nor anyone else would treat the continuity of my personhood as an illusion.
Yet that is not true of the proverbial pair of boots inherited from ones great-grandfather, which had been resoled six times and had three new sets of uppers. Admiral Nelson’s HMS Victory, they say, is only 10% original: after another century of restorations it may still attract tourists, but will have no actual physical connection with the Battle of Trafalgar. There will be no real continuity of form – but there is in our case as humans, and there is in my dog’s or your cat’s case, too.
The trouble is that the concept of “me” that distinguishes us as real entities from a warship or a pair of shoes has no material explanation, on the very principle of nominalism on which biology now is based. If there are no universals in biology governing the forms of organisms (and if they are forbidden anyway because they are not efficient causes), then there are also no minds that transcend whatever material things you can name, like molecules, genes or cells.
The fact that naturalist biology, and the Theory of Evolution in particular, has absolutely no way to account for this fundamental truth of form (which, as I’ve shown, affects morphology, medicine and the whole of human experience) is a major epistemological failure, is it not? It actually contradicts reality, which ought to be a problem for accepting it as genuine knowledge.
The ironic thing is that correcting that failure is excluded in principle by a thing called methodological materialism. So I guess people will continue to shrug off the confusing philosophical stuff and get on with evolutionary biology as before, whilst fudging the biological universals (by continuing to classify organisms), fudging the biology (by assuming homeostasis without any way of explaining it) and fudging our own personhood (by still regarding our past research, degrees and Nobel Prizes as “ours”).
But the problem is this – if these non-material universals like form, normality and mind actually exist, then in all probability they have a bearing on the true nature of origins, too. To be blind to reality in one area is to be blind in all.