The previous chapter was more about Darwinism than philosophy; this one is more about philosophy than Darwinism. It uses controversy about the truth of Darwin's theory to introduce wider questions about epistemology and philosophy of science, and to disentangle different kinds of scepticism.
Scientists now claim that the essentials of the Darwinian theory have been established beyond any doubt, and this chapter addresses the question of whether they are entitled to any such claim. It does not deal (except in outline) with the scientific arguments for certainty, but addresses the wider question of whether we are ever justified in claiming certainty for anything. This raises two levels of question. The first, which comes into philosophy of science, is about the claim that whatever scientists discover may always be overthrown by later evidence. The second is about radical philosophical scepticism, and introduces briefly the subjects of metaphysics and epistemology.
Philosophical scepticism is often treated as a subject of purely academic interest, but it becomes of practical relevance when it is inadvertently entangled with questions about the strength of scientific evidence. The last section of this chapter distinguishes specific doubts about Darwinian theory from all-encompassing doubts of different kinds, and in doing so draws distinctions between levels of argument that will be crucial in later chapters. It also makes use of these issues to introduce the problems of practical decision-making against a background of ignorance and uncertainty, which will reappear in the discussion of politics in Chapter 9.
It is all very well to say that Darwinian ideas present threats to deeply rooted ideas about ourselves, but whether any or all of these threats are fulfilled depends in the first instance on whether the theory is true. If it is not, we have no need to worry about its potentially alarming implications. And, as is well known, many people still resist the Darwinian account of our origins altogether.
The most energetic and conspicuous of these are the spiritual heirs of the Victorian fundamentalists: the so-called creationists, who still flourish in America, and whose starting point is a conviction of the literal truth of the Genesis account of creation. Nearly all systematic resistance to Darwinism as a whole comes from religion (which is not, of course, to say that all religions resist all aspects of Darwinism). Still, it is also worth mentioning doubts of a more diffuse kind. According to the Darwinian biologist John Maynard Smith:
Something very odd has happened during the past five years or so. The public has been persuaded that Darwinism, as an explanation of evolution, has been exploded.