In its original version, before Wittgenstein decided to extend the book’s scope, the Tractatus advanced a solipsism of a decidedly etiolated sort – so etiolated, indeed, that the self which according to this solipsism claims ownership of the world ends up stripped of any substantial content. By the time it was published, however, the solipsism passage had been revised so as to gesture towards a puzzling ‘metaphysical’ subject, whose importance seems to be primarily (though no doubt not exclusively) ethical. By the time he wrote the Blue Book Wittgenstein no longer held the unitary conception of language on which his Tractarian conception of solipsism depended, but he continued to deny coherence of a substantial self.