Peter Singer, known for his involvement with the animal liberation movement, was also a student of Hare's, and has explicitly adopted some elements of Hare's thought, though not his doctrine of universal prescriptivism.
Peter Singer, keda tuntakse osalemise tõttu loomade vabastusliikumises, oli samuti Hare'i õpilane ning on otsesõnu laenanud mõned Hare'i teooriate elemendid, ehkki mitte tema universaalse preskriptivismi doktriini.