Derek Parfit

Derek Parfit (1942–2017) was a British moral philosopher and fellow of All Souls College, Oxford, widely regarded as one of the most influential philosophers of the late 20th century. His major works include *Reasons and Persons* (1984), which fundamentally reshaped debates in ethics, metaphysics, and population ethics through his analysis of personal identity and the non-identity problem. Parfit argued that personal identity is not what matters; what matters is psychological continuity and connectedness, a view that challenged traditional assumptions about the self and had profound implications for ethics and rationality.

In *On What Matters* (2011), his final major work, Parfit attempted to reconcile consequentialism, contractualism, and Kantian ethics, arguing that these seemingly opposed frameworks converge on similar conclusions about how we ought to live. His work on population ethics—particularly the "repugnant conclusion" problem—became foundational to discussions of climate change, existential risk, and long-term future ethics. Parfit's influence extends beyond academic philosophy into effective altruism and future studies, where his arguments about the moral significance of future generations inform contemporary thinking on existential risk and humanity's long-term trajectory.

Derek Parfit was a British moral philosopher at Oxford University whose work on personal identity and ethics fundamentally shaped contemporary philosophy. His *Reasons and Persons* became a canonical text in ethics, population ethics, and metaphysics. Parfit's arguments about the moral significance of future generations and the non-identity problem have become central to effective altruism and existential risk discourse.