 Now (1) seems correct: if I am a brain-in-a-vat then, given externalism, my symbol ‘tree’ cannot refer to trees since there aren’t any trees in the vat-world—a BIV’s ‘tree’ symbol refers to \(v\)-trees, not trees. But what reason do we have to believe (2)? If we are BIVs won’t our ‘tree’ symbols refer to v-trees rather than trees? Crispin Wright [1992b] argues that all language-users, whether humans or brains-in-a-vat, can be certain of (2) since they can know they use language meaningfully and thus can know that their language disquotes. Graeme Forbes [1995] questions Wright’s argument. 