  The most distinctive features of ethical intuitionism are its epistemology and ontology. All classical intuitionists maintain that  basic moral propositions are  self-evident,[1]  and that moral properties are non-natural properties. So the discussion of intuitionism will focus on just these two features. Some philosophers claim that ethical pluralism (the view that there is an irreducible plurality of basic moral principles, and that there is no strict priority of any one principle over another) is an essential feature of intuitionist thought, but not all intuitionists are pluralists, e.g., Sidgwick and Moore, so this feature will not be discussed here.