Aside from his remarkable studies in psychology and the social sciences, Donald Thomas Campbell (1916–1996) made significant contributions to philosophy, particularly philosophy of science,epistemology, and ethics. His name and his work are inseparably linked with the evolutionary approach to explaining human knowledge (evolutionary epistemology). He was an indefatigable supporter of the naturalistic turn in philosophy and has strongly influenced the discussion of moral issues (evolutionary ethics). The aim of this paper is to briefly characterize Campbells work and to discuss its (...) philosophical implications. In particular, I show its relevance to some current debates in the intersection of biology and philosophy. In fact, philosophy of biology would look poorer without Campbells influence. The present paper is not a hagiography but an attempt to evaluate and critically discuss the meaning of Campbells work for philosophy of biology and to encourage scholars working in this field to read and re-read this work which is both challenging and inspiring. (shrink)