in 1974 from the University of Oxford – where his supervisor was R. M. Hare – for a thesis on "Rules and Consequences as Grounds for Moral Judgment".
[1] Frey authored Interests and Rights: The Case Against Animals (1980), Euthanasia and Physician-Assisted Suicide (1998, with Gerald Dworkin and Sissela Bok), and The Oxford Handbook of Animal Ethics (2011, with Tom Beauchamp, eds.).
Frey was a critic of animal rights but as noted by David DeGrazia was one of five authors – along with Peter Singer, Tom Regan, Mary Midgley, and Steve Sapontzis who had made significant philosophical contributions to the work of placing animals within ethical theory.
[2] The importance of Frey's Interests and Rights, according to DeGrazia, lay in its rigorous treatment of the problem of animal minds and moral status.
They are barren of preferences, wants, and desires; they lack memory and expectation; and they are unable to reason, plan, or intend.