In philosophy|lang=en terms the difference between idealism and cognitivism
is that
idealism is (philosophy) an approach to philosophical enquiry which asserts that direct and immediate knowledge can only be had of ideas or mental pictures while
cognitivism is (philosophy) the view that ethical sentences express propositions and are therefore capable of being true or false.
As nouns the difference between idealism and cognitivism
is that
idealism is the property of a person of having high ideals that are usually unrealizable or at odds with practical life while
cognitivism is (philosophy) the view that ethical sentences express propositions and are therefore capable of being true or false.