John Rawls (1921-2002) on the Moral Status of Animals

Last of all, we should recall here the limits of a theory of justice. Not only are many aspects of morality left aside, but no account is given of right conduct in regard to animals and the rest of nature. A conception of justice is but one part of a moral view. While I have not maintained that the capacity for a sense of justice is necessary in order to be owed the duties of justice, it does seem that we are not required to give strict justice anyway to creatures lacking this capacity. But it does not follow that there are no requirements at all in regard to them, nor in our relations with the natural order. Certainly it is wrong to be cruel to animals and the destruction of a whole species can be a great evil. The capacity for feelings of pleasure and pain and for the forms of life of which animals are capable clearly imposes duties of compassion and humanity in their case. I shall not attempt to explain these considered beliefs. They are outside the scope of the theory of justice, and it does not seem possible to extend the contract doctrine so as to include them in a natural way. A correct conception of our relations to animals and to nature would seem to depend upon a theory of the natural order and our place in it. One of the tasks of metaphysics is to work out a view of the world which is suited for this purpose; it should identify and systematize the truths decisive for these questions. How far justice as fairness will have to be revised to fit into this larger theory it is impossible to say. But it seems reasonable to hope that if it is sound as an account of justice among persons, it cannot be too far wrong when these broader relationships are taken into consideration.

(John Rawls, A Theory of Justice [Cambridge: Harvard University Press, Belknap Press, 1971], 512)