The day may come when the rest of animal creation may acquire those rights which never could have been withheld from them but by the hand of tyranny. The French have already discovered that the blackness of the skin is no reason why a human being should be abandoned without redress to the caprice of a tormentor. … What else is it that should trace the insuperable line? Is it the faculty of reason, or perhaps the faculty of discourse? … The question is not, Can they reason? nor Can they talk? but, Can they suffer?” wrote Jeremy Bentham in The Principles of Morals and Legislation. This week we look at the implications of the philosophy of naturalism.