The extreme thesis that only the self exists. It arises from the view that only the self can be known with any certainty. On this view of things, it can be acknowledged that other consciousnesses may exist, but since those consciousnesses cannot be known their existence must remain speculative. Because of its anti-foundationalism stance, postmodern philosophy is frequently accused of solipsism, as were many of the key post-structuralism figures like Derrida, Jacques and Foucault, Michel.