In The Biological Foundations of Bioethics (2015) Tim Lewens states that which phenotypes are regarded as pathological should not be “hostage to evolutionary enquiry”. In this talk, Griffiths will disagree, and discuss some ways in which recent advances in biology ought to change ideas about health and disease. Amongst other things, he suggest that the health of an organism and the quality of its environment are entwined conceptually, as well as causally.