Regan is a well-known figure in the animal liberation movement. His The Case for Animal Rights (1983) is a systematic and scholarly defense of the controversial claim that animals have rights that humans are morally obligated to recognize and respect. Arguing against the views of earlier philosophers like René Descartes, who claimed that animals are machinelike and incapable of having mental states such as consciousness or feelings of pleasure or pain, Regan attempts to show that such a view is misguided, muddled, or incorrect.

Regan was born in Pittsburgh, Pennsylvania. He attended Thiel College and the University of Virginia, where he earned his doctorate in philosophy. Before publishing The Case for Animal Rights, Regan also edited Animal Rights and Human Obligations (1976) and Matters of Life and Death (1980).

Within the...