Since my schooldays I have had reservations about the theory of evolution. Not that it is wrong, rather that it is silent about what we now most need to know. This can scarcely be a criticism of Darwin who was writing before the findings of Mendel were published and long before the discovery of the structure of DNA.
Darwin, sometime after the publication of The Origin of the Species, wrote ‘ I cannot avoid the conviction that no innate tendency to progressive development exists.’
My sense is that he was mistaken in this belief, but I shall not attempt to argue it here. I will however quote two remarks by Vladimir Nabokov and Ludwig Wittgenstein which show that they were unconvinced that the theory as recently understood could explain the enormous multiplicity of life forms.
‘Butterfly mimicry has a subtle exuberance and luxury far in excess of a predator’s power of appreciation’ – Nabokov
‘ I have always thought that Darwin was wrong: his theory does not account for all the variety of species. It hasn’t the necessary multiplicity’ – Wittgenstein (a remark recorded by M. O’Drury)
Of course these considerations need not require us to suppose there is some deus ex machina directing evolution. However there is a dogma which crystallised the success of Darwinism over Lamarckism which is worth mentioning. In 1892 August Weismann proposed a barrier between the ‘immortal’ germ cell lineages producing the gametes (haploid spermatozoa and ova) and the ‘disposable’ somatic cells. More precisely hereditary information can move only from the germ cell line to the somatic line, absolutely not in the other direction. This anticipates a central dogma of molecular biology that hereditary information travels from DNA to RNA to proteins and not the other way.
What seems to me to be lacking in our understanding of evolution is a convincing account of how living forms have become progressively more complicated over time (with fallings off and extinctions too). I feel it likely this is because of our limited understanding of the behaviour of macromolecules, proteins and the nucleic acids in particular.
Let me conclude with three literary quotations:-
Osip Mandelstam wrote a wonderful poem ‘Lamarck in 1932, wich is really concerned with the horrors of Stalin’s regime. It pictures Lamarck escorting Mandelstam down through the phyla, like Vergil guiding Dante, without possibility of return. I quote part of Brown and Merwin’s outstanding translation.
If all that's alive is no more than a blot on the brief escheated day, give me the last rung on Lamarck's moving ladder.p I'll hiss myself down throughthe lizards and sea snakes to the annelid worms and sea-slugs... He said 'Nature's a shambles. There's no vision. You're seeing for the last time.' 'Nature has gone away from us as though she didn't need us. She's slid the oblong brain into a dark sheath, like a sword. She's forgotten the drawbridge. She lowered it late for those with a green grave, red breath, sinuous laughter...'
Three lines from my poem The Past, written in 2017, doubting the absoluteness of Waismann’s barrier. The ground for doubt would be the interconnectedness of the parts in living organisms.
Mistaken to picture our seed running through lived lives, a twist of exempted gold.
Finally: ‘Facts point in all directions like the thousand twigs of a tree. It is only the life of the tree that gives unity and goes up’ G.K.Chesterton