R. M. Hare
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Hare is best known for his development of prescriptivism as a meta-ethical theory, which he argues is supported by analysis of formal features of moral discourse, and for his defence of preference utilitarianism based on his prescriptivism.
Some of Hare's students, such as Brian McGuinness, John Lucas, and Bernard Williams went on to become well-known philosophers. Hare's son, John E. Hare, also became a philosopher. Peter Singer, known for his involvement with the animal liberation movement (who studied Hare's work as an honours student at the University of Melbourne and came to know Hare personally while he was an Oxford BPhil graduate student), has explicitly adopted some elements of Hare's thought, though not his doctrine of universal prescriptivism. Provided by Wikipedia