  Quine’s argument for this position relies on holism. This is the claim that most of our sentences do not have implications for experience when they are taken one-by-one, each in isolation from the others. What has experiential implication is, in most cases, not an individual sentence but a larger chunk of theory. Holism is not a very controversial doctrine. (Carnap accepts it; see Carnap, 1934, 318.) Quine claims that holism shows that most of our sentences are not justified by the relation of the individual sentence, considered in isolation, to experience. Almost always, what matters is the relation to experience of some larger chunk of theory (in principle, although perhaps never in practice, of the theory as a whole). This means that in principle the correctness of a given claim is almost never settled simply by looking at the empirical evidence for that claim alone. Other factors will play a role, in particular the way in which accepting the given claim would contribute to the efficacy and simplicity of the theory as a whole. But these are precisely the ‘pragmatic factors’ which Carnap thought played a role in the choice of language. In arguing that such factors play a role throughout our knowledge, Quine accepts ‘a more thorough pragmatism’ (1951, 46) which puts Carnap’s external changes on the same epistemological footing as his internal changes. (Quine’s early account of these matters is extremely sketchy. For elaboration, see Quine 1991 and 1996; for criticism of the sketchy account, see Sober 2000.)