 Ross does, of course, acknowledge errors exist in our moral thinking. Indeed, it is, he says, ‘a mistake to assume that all . . . [our] convictions are true, or even that they are all consistent; still more, to assume they are all clear’ (FE 1). Like some sense perceptions in science, he says, some of our moral convictions may have to be discarded as illusory (RG 41). They are not discarded at the behest of a theory. Instead, they are to be rejected, Ross says, ‘only when they are in conflict with other convictions which stand better the test of reflection’ (RG 41). The aim of moral philosophy is to compare our moral convictions with each other, ‘and to study them in themselves, with a view to seeing which best survive such examination, and which must be rejected either because in themselves they are ill-grounded, or because they contradict other convictions that are better grounded; and to clear up, so far as we can, ambiguities that lurk in them’ (FE 1; also FE 2–3, 190). 