Denis Walsh is (primarily) a philosopher of biology at the Department of Philosophy and the Institute for the History and Philosophy of Science at the University of Toronto. His biology PhD dissertation research (McGill) was in systematics and evolution. His philosophy PhD dissertation (London) was in metaphysics and modal logic. From 2005 until 2015 he held the Canada Research Chair in Philosophy of Biology. In recent years his research has concentrated on the concept of natural agency. His 2015 book Organisms, Agency, and Evolution explored the implications of natural agency for evolution. His current research concentrates on the methodological challenges of studying agency scientifically.