  Prior’s point is that the features of negation that are relevant to Russell’s paradox or the Liar paradox are exhausted by its status as a Curry connective. This makes clear why these paradoxes do not depend on features of negation, such as excluded middle or double negation elimination, that fail to hold in nonclassical theories where negation remains a Curry connective (e.g.,  in intuitionistic theories, where ECQ and Red both  hold).[27] 