  What this criticism amounts to is the complaint that we need to be able to make sense of cases in which there are moral reasons on both sides, for and against. But we cannot do this effectively if all moral reasons are specified in absolute principles. Morality cannot, therefore, be just a system of absolute principles. The only way in which we could continue to think of morality as governed by absolute principles is to suppose that there is only one such principle, so that there is no possibility of conflict between principles, or to arrange things in some other way so that the principles are incapable of conflict. (Even then, of course, there would be the worry that conflict is real, and that to arrange things so that conflict is merely apparent is to erase something important.) We know of one position that offers only one principle: classical utilitarianism. The argument against this ‘monistic’ position is rather different. The argument is the direct claim that monism is false; there is more than one sort of relevant property, or more than one way in which features can get to be morally relevant. So a position with only one absolute principle is false, and one with more than one such principle cannot make proper sense of conflict.