Do we need to prove the existence of the ‘external’ world?

Abstract

In this paper, I defend Wittgenstein’s insight that Cartesian-style skeptical arguments against the existence of the external world are not false, but linguistic confusions that violate the constitutive rules of our epistemic practices. To do this, I advance a resolutely grammatical interpretation of his later notebooks, posthumously published as On Certainty, where so-called ‘hinge-propositions’ function as rules of grammar and logically exclude the possibility of ‘global’ doubt. I then defend this reading from two notable objections by Crispin Wright, namely that (1) if ‘hinges’ are not semantically truth-apt propositions, they cannot function as premises in logical inferences, and (2) the groundless nature of grammatical propositions renders the foundation of our language-game arbitrary, leaving us unable to distinguish a rational world-picture from mere dogma.