Current secular thought strongly and almost wholly embraces Charles Darwin’s specific theory of evolution set out in his 1859 ‘The Origin of Species’. This is very often associated with an atheist position, since evolution is seen as trouncing religious creationism, or later theories of ‘intelligent design’. This link is both unnecessary and unfortunate. Atheism may well include evolution, but is a sufficiently strong hypothesis which does not crucially or uniquely rely on evolution. Making atheism rely on specific Darwinian evolution is a mistake which forces the current dominant secular paradigm to defend the Darwinian account in all its detail. This leads to partisan rather than intellectual positioning, and precludes the doubt and debate on Darwin which would otherwise be core to the Enlightenment project. Neo-Darwinism becomes a secular fundamentalism.
From 1859 onwards, there have been, and there remain, credible doubts about the Darwinian account of evolution. Admitting these does not imply a creationist view. Precluding them prohibits intellectual progress.
Darwin’s theory rests on 8 crucial assumptions
- Prolific reproduction of species (2 elephants will produce 15m elephants in 500 years)
- A resource constraint
- Random mutations
- Inheritance of characteristics through ‘blending’
- Natural selection by predation rather than climate or catastrophe
- Geographic isolation
- Cumulative change
- Time, where Darwin suggested a 300 million year process
Not all these assumptions hold. For example, human reproduction is consciously constrained by contraception and abortion. Darwin insisted that mutations are random, and selection logical. It is entirely possible that the reverse could hold, ie that mutations are adaptive, as more recent neo-Lamarckian research suggests, and selection a random process of predation, chance, catastrophe etc. Saltation may be a better explanator than mutation.
The species barrier remains one of the great questions in biology. It is the crossing of this barrier that Darwin addresses, and his continuous incremental theory does have a problem in explaining a discrete process of speciation. If the definition of a species is reproductive isolation, ie organisms that can reproduce to yield fertile offspring, then crossing such a discrete barrier by a slow incremental process is problematic. How does the first organism in a new species find a mate capable of fertile reproduction?
Gregor Mendel’s work on dominant genes in peas rescued Darwin’s theory from blending of new mutations back into the host population. W D Hamilton’s theory of the ‘selfish gene’ responded to altruism as a challenge to Darwin by claiming that only relatives in a species carrying the same gene display altruism. This claim is made more in complex mathematical models than it is in empirical study. Hamilton was himself a determined eugenicist. Nevertheless, his theory has been widely popularised by Richard Dawkins, thus establishing the current Darwin/Mendel/Hamilton synthesis.
As Darwin’s contemporary, Richard Owen, whom Darwin called ‘our greatest palaeontologist’ pointed out, Darwin’s theory is not capable of unambiguously telling the evolutionary story of one single species. There is room for doubt. There is a huge need for debate, and for further intellectual development, an evolution of Darwinian thought itself.