Transmission and Closure

Abstract

Crispin Wright's paper pursues and illuminates important questions both about the nature of warranted belief in general and about what may be wrong with two widely discussed philosophical arguments-an argument given by Michael McKinsey which seems to bring out an inconsistency between externalism about content and first-person privileged access and Hilary Putnam's famous 'proof' that we are not brains in a vat. Central to Wright's discussion is a principle of transmission of warrant, which says, roughly, that a warrant to believe a proposition p can be transferred to a further proposition q if q is deducible from p. Wright contrasts transmission with another principle-closure-which he characterises as follows: Closure, unrestricted, says that whenever there is warrant for the premisses of a valid argument, there is warrant for the conclusion too. The principle of transmission gains plausibility from the evident fact that in very many cases, a warrant for one proposition may indeed be transmitted by valid inference to another. But while transmission holds in very many cases, it does not-Wright argues hold unrestrictedly. His principal theses are two: first, that the McKinsey argument is vitiated by a certain quite subtle kind of failure of transmission and, second, that contrary to what we may be tempted to