Abstract
It is often said that Darwin’s study of nature drove him to atheism. Whereas this might be, in principle, possible, it does not seem to have actually been the case for him. Both in his autobiography, which was not intended to be published, and in his personal correspondence, Darwin consistently described himself as an agnostic. It is true that he underwent several fluctuations of belief during his life, but in the end, he never explicitly rejected the existence of God. What is even more important is that the main shift he underwent during his life was conceptual, not emotional or religious. That was his shift from natural theology and a view of adaptation as perfect to natural selection and a view of adaptation as relative to the environment, something historian Dov Ospovat pointed out 40 years ago. In this chapter, I present the evidence from Darwin’s writings about his agnosticism and about his conceptual shift from the perfect adaptation of natural theology to the relative adaptation of natural selection.