Naturalism in ethics

Ethical naturalism is the project of fitting an account of ethics into a naturalistic worldview. It includes nihilistic theories, which see no place for real values and no successful role for ethical thought in a purely natural world. The term ‘naturalism’ is often used more narrowly, however, to refer to cognitivist naturalism, which holds that ethical facts are simply natural facts and that ethical thought succeeds in discovering them.

G.E. Moore (1903), attacked cognitivist naturalism as mistaken in principle, for committing what he called the ‘naturalistic fallacy’. He thought a simple test showed that ethical facts could not be natural facts (the ‘fallacy’ lay in believing they could be), and he took it to follow that ethical knowledge would have to rest on nonsensory intuition. Later writers have added other arguments for the same conclusions. Moore himself was in no sense a naturalist, since he thought that ethics could be given a ‘non-natural’ basis. Many who elaborated his criticisms of cognitivist naturalism, however, have done so on behalf of generic ethical naturalism, and so have defended either ethical nihilism or else some more modest constructive position, usually a version of noncognitivism. Noncognitivists concede to nihilists that nature contains no real values, but deny that it was ever the function of ethical thought to discover such things. They thus leave ethical thought room for success at some other task, such as providing the agent with direction for action.

Defenders of cognitivist naturalism deny that there is a ‘naturalistic fallacy’ or that ethical knowledge need rest on intuition; and they have accused Moore and his successors of relying on dubious assumptions in metaphysics, epistemology, the philosophy of language and the philosophy of mind. Thus many difficult philosophical issues have been implicated in the debate.