Charles Darwin
Notes
Charles Darwin (1809–1882), English naturalist. On the Origin of Species (1859) set out the theory of evolution by natural selection, the single most important idea in biology and, in my view, in the whole of science, because it explained the appearance of design without a designer. He arrived at it without knowledge of genetics and acknowledged the gap; Gregor Mendel's work, which filled it, was lying unread in a journal throughout his later life. Described himself in late life as an agnostic.
Wikipedia: https://en.wikipedia.org/wiki/Charles_Darwin