ABSTRACT
The explanation of a priori knowledge which is possibly still the most popular among analytic philosophers is that it is at bottom linguistic, in some sense knowledge of linguistic rules and nothing more. It would seem to follow directly that the ability to reason deductively and to spot any sort of logical or conceptual relationship is to be explained as a form of linguistic competence, and that rational 'intuition', in Locke's sense, can be nothing but a type of linguistic intuition. Yet there are notorious difficulties for such a view, starting with Descartes' response to Hobbes, that 'a Frenchman and a German are able to reason in exactly the same way about the same things'.137 There seems to be a clear distinction between understanding an argument as a bit of (say) English, and understanding or getting the point of the reasoning. Indeed a failure to reason correctly seems so far from being a sign that the sentences in question are not fully understood, that, unless they are fully understood, the case cannot be one of invalid reasoning. The linguistic competence required for an understanding of the sentences seems to be one thing, the reason or intelligence required to follow or assess the argument quite another. The ability to construct proofs is something else which is naturally included under a facility with ideas rather than with language.
