Canadian-born Oxford political philosopher; Chichele Professor of Social and Political Theory from 1985 to 2008, fellow of All Souls, and the founding figure of Analytical Marxism (the "September Group," or "non-bullshit Marxism" in his own label). Cohen was born in Montreal in 1941 to working-class Jewish communist parents; the inheritance was lifelong. He trained at McGill, then at Oxford under Isaiah Berlin and Gilbert Ryle, and spent his career applying analytic philosophical tools to the two traditions he cared about most: Marx, and the egalitarian liberalism of Rawls and Nozick.
His first major book, Karl Marx's Theory of History: A Defence (1978), was the rigorous reconstruction of Marx's historical materialism that the analytic tradition had been presumed incapable of producing. It established Cohen as the most serious Marxist philosopher writing in English and set the agenda for Analytical Marxism: Marx's claims treated as propositions to be tested, not doctrines to be defended. History, Labour, and Freedom (1988) extended the project; by the 1990s Cohen had drifted away from Marx's labor theory of value and toward direct engagement with the liberal-egalitarian tradition.
The move produced his most distinctive late work. Self-Ownership, Freedom, and Equality (1995) showed that the libertarian premise of self-ownership — Nozick's foundation — is harder to reconcile with egalitarian commitments than socialists had assumed. Cohen concluded that socialists should give up self-ownership rather than equality. Rescuing Justice and Equality (2008) was the book-length quarrel with Rawls. The difference principle, Cohen argued, is too generous to the talented, who exploit their superior bargaining position to extract incentive payments that a truly just society would not tolerate. Justice, for Cohen, applies not only to the basic structure of society but to the choices of individuals within it — an argument that pushed egalitarianism into territory Rawls had left uncontested. Why Not Socialism? (2009), a short late essay built around an imagined camping trip, distills the view into a few dozen pages.