Subject of a life

A term first defined by moral philosopher and animal rights activist Tom Regan in The case for animal rights.

Regan says that any living being with beliefs, desires, perception, memory, a sense of the future, an emotional life, preferences, the ability to act to achieve goals, a continuous identity, and so on is a subject of a life, and that every subject of a life has moral rights (in the first edition, 1983).

In the 1983 first edition, Regan used the criterion of “mentally normal mammals aged one year or older.” In the preface to the 2004 revised edition, he broadened his position to include birds (while withholding judgment on fish).

Why do we need the concept of a subject of a life?

Regan defends animal rights on the basis of Kant’s deontology. But Kant’s formula of humanity does not recognize animal rights. Kant says that only persons, a subset of humans, have moral rights and duties, and argues that animals, which cannot fulfill moral duties, have no rights either.

Regan sees the problem as arising because Kant’s concept of a human is too broad, while his concept of a person is too narrow, and proposes the new concept of a subject of a life as an alternative.

According to Regan, any living being with beliefs, desires, perception, memory, a sense of the future, an emotional life, preferences, the ability to act to achieve goals, a continuous identity, and so on is a subject of a life. All subjects of a life have equal inherent value and have moral rights.

See also

• A somewhat different concept from sentience as discussed in consequentialism.