  Charles Darwin was not, as we use the term today, a philosopher, though he was often so described during his  lifetime.[2]  Nevertheless, for an encyclopedia of philosophy what is needed is a discussion of the impact of philosophy on Darwin’s Darwinism, and the impact of Darwin’s Darwinism on topics that both he, and we, would consider philosophical. We focus here on the impact of philosophical discussions about the nature of science during Darwin’s lifetime on Darwin’s scientific research, thinking and writing; and on the impact of that research, thinking and writing on philosophy.  Taking the time to do such philosophical archaeology  stems from a conviction that if the concept of Darwinism has legitimate application today, it is due to a set of principles, both scientific and philosophical, that were articulated by Darwin and that are still widely shared by those who call themselves ‘Darwinians’ or ‘neo-Darwinians’. 