Moral Skepticism
Those who deny that an objective foundation, or basis, of morality exists are commonly referred to as moral skeptics. Moral skepticism can take various forms.
Moral nihilists, for example, claim that there simply are no moral facts. Moral nihilists point to irresolvable moral disagreements as evidence of the correctness of their view.
Take, for example, the ethics of war. If there is a fact of the matter about the morality of war – be it that war is immoral or that war is in some cases justified – the moral nihilists claims that we should be able to settle disagreements about the morality of war by pointing to that fact. Thus, we should be able to determine who is right and who is wrong in a disagreement between a pacifist and a warmonger.
It seems, however, that there is no fact of the matter to which we can point. As the disagreement is irresolvable (in any case, the dispute is centuries old – and ongoing, that is, it hasn’t yet been resolved), the nihilist asserts that there is no fact of the matter about the morality of war. More generally, the moral nihilist claims that there is no fact of the matter about morality; there are no moral facts.
Moral relativists, on the other hand, hold that there are moral facts, but that they are either relative to (a) the individual (this is known as personal moral relativism) or they are relative to (b) the moral norms, or conventions, of the culture from which they came (this is known as cultural moral relativism).