What are moral principles? The assumption underlying much of the generalism–particularism debate in ethics is that they are (or would be) moral laws: generalizations or some special class thereof, such as explanatory or counterfactual-supporting generalizations. I
argue that this law conception of moral principles is mistaken. For moral principles do at least three things that moral laws cannot do, at least not in their own right: explain certain phenomena, provide particular kinds of support for counterfactuals, and ground moral necessities, “necessary connections” between obligating reasons and obligations. Moreover, neither a best-systems theory of moral principles nor any of the competing theories of moral principles proposed by Sean McKeever and Michael Ridge, Pekka Väyrynen, and Mark Lance and Margaret Little could vindicate the law conception of moral principles. I conclude with some brief remarks about what moral principles might be if they are not moral laws.