Sometimes today we sloppily bracket 'atheist' and 'agnostic' together, as if they meant the same thing. The newly minted word in Darwin's time had a more precise meaning, 'not knowing'. That this should not be confused with the word 'atheist', is made clear by Darwin himself in a letter to John Fordyce of 1879; he wrote this:
It seems to me absurd to doubt that a man may be an ardent theist and an evolutionist. You are right about [Charles] Kingsley. Asa Gray, the eminent [American] botanist, is another case in point.... In my most extreme fluctuations I have never been an atheist in the sense of denying the existence of a God.
So Darwin, on his own account was never an atheist, but fluctuated between theism and agnosticism.
~ John Marsh












