Derek Parfit
British · 1942–2017
Derek Parfit was a British moral philosopher at All Souls College, Oxford, whose work on personal identity, rationality, and ethics is among the most influential in twentieth-century analytic philosophy. His book Reasons and Persons (1984) argued that our ordinary concept of personal identity is not what matters in survival, with implications that ripple through ethics, population theory, and the philosophy of time. Known for an almost monastic dedication to his work — reading and writing constantly, famously eating simple food so he could keep one hand free for a book — he published relatively little but transformed every field he touched.