 It should be noted that the ‘non-transitivity of accessibility’ response is distinct from an even more radical response, which rejects the principle of the transitivity of identity—a principle definitive of the classical notion of identity. For example, Priest (2010) denies the transitivity of identity in the context of his dialetheism about truth and a paraconsistent logic in which the material conditional does not obey the principle of modus ponens. Discussion of this extreme position is, however, beyond the scope of this article. (On dialetheism and paraconsistent logic, see the separate entry on Dialetheism. On the logic of identity, see the entry on Identity.)