Ethical naturalism holds that ethical facts about such matters as good and bad, right and wrong, are part of a purely natural world — the world studied by the sciences. It is supported by the apparent reasonableness of many moral explanations. It has been thought to face an epistemological challenge because of the existence of an “is-ought gap”; it also faces metaphysical objections from philosophers who hold that ethical facts would have to be supernatural or “nonnatural,” sometimes on the grounds (...) that ethical thought has a practical role that no thought about purely natural facts could have. Its defenders have argued resourcefully against these challenges. (shrink)

This book defends a form of ethical intuitionism, according to which (i) there are objective moral truths; (ii) we know some of these truths through a kind of immediate, intellectual awareness, or "intuition"; and (iii) our knowledge of moral truths gives us reasons for action independent of our desires. The author rebuts all the major objections to this theory and shows that the alternative theories about the nature of ethics all face grave difficulties.