Internal and External: Meaningful and Meaningless

Abstract

Abstract Chapter 5 considers the challenge to scepticism that both the sceptical conclusion and the problem about our knowledge of the external world to which it is a response are equally meaningless. This line of criticism, which has been presented forcefully by Rudolf Carnap in his papers ‘Empiricism, Semantics and Ontology’ and ‘Pseudoproblems in Philosophy’, is inspired by verificationism in the philosophy of language: the view that a sentence that is not rendered at least more likely to be true by one possible course of sensory experience than another has no meaning, and thus cannot be considered either true or false. On the basis of the verifiability principle, Carnap argues that only ‘internal’ questions about knowledge – questions that pertain to some empirically verifiable matter of fact – can be meaningfully asked; by contrast, the question whether there are any material objects at all, taken as an ‘external’ question by the sceptic, is literally meaningless, and should instead be understood as a merely ‘practical’ question about which ‘linguistic framework’ to adopt. Stroud observes, first, that this strategy not only appreciates the force of philosophical scepticism but is in fact in complete agreement with it: it denies that there is any theoretical justification for adopting one linguistic framework, such as that of a world of material objects, rather than another, which is precisely the point the sceptic wants to make; and it accepts a version of the ‘conditional correctness of scepticism’. The view that, if the traditional philosopher did manage to raise a meaningful question about our knowledge of the world, then his sceptical answer to it would be correct. Second, Stroud argues that neither the ‘internal’–‘external’ distinction used in the argument against scepticism nor the status of the verifiability principle itself on which it rests are made sufficiently clear to render them efficient and acceptable; moreover, as long as the verifiability principle is not independently shown to be a condition of meaningfulness, philosophical scepticism will itself provide a powerful objection to it.