The deepest challenge in moral epistemology, as in general epistemology, is raised by a skeptical regress argument: Someone is justified in believing something only if the believer has a reason that is expressible in an inference with premises that the believer is already justified in believing. This requires a chain of inferences that must continue infinitely, close into a circle, or stop arbitrarily. Academic skeptics reject all three options and conclude that there is no way for anyone to be justified in believing anything. The same regress arises for moral beliefs . . . The simplest way to stop this regress is simply to stop. If a believer can work back to a premise that the believer is justified in believing without being able to infer that premise from anything else, then there is no new premise to justify, so the regress goes no further. That is how foundationalists stop the regress in general epistemology. Moral intuitionists apply foundationalism to moral beliefs as a way to stop the skeptical regress regarding moral beliefs.