Is moral naturalism ruled out by the fact that morality is normative? I want to consider this question in a systematic way, explaining the central thesis of moral naturalism as I understand it, and then clarifying the idea of normativity. The chief point that I want to make is that the issue raised by this question is much more complex than it might seem to be, mainly because of complexity in what philosophers have in mind when they speak of morality as “normative.” There are several dimensions to the complexity, but the dimension I will stress is that philosophers disagree about what we might call the ‘stringency’ of moral normativity. I will distinguish three ‘grades of normativity.’ I will investigate, for each of these grades, the plausibility of the idea that morality has that grade of normativity, and the viability of naturalistic accounts of it. My conclusion will be tentative, but it will be optimistic for moral naturalism.

Moral naturalism holds that in thinking of things as morally right or wrong, good or bad, we ascribe moral properties to these things – properties such as moral rightness and wrongness, goodness and evil. It holds that there are such properties, and it adds that these properties are ordinary garden-variety natural properties – properties that have the same basic metaphysical and epistemological status as the properties a tree can have of being deciduous, and the property a piece of paper can have of being an Australian twenty-dollar bill.