Sven Bernecker

Sections 1 and 2 examine Hilary Putnam's brain-in-a-vat argument and an analogous argument by Fred Dretske and show that anti-skeptical arguments from semantic externalism presuppose that we can know non-empirically that we possess beliefs and thus aren't zombies. In section 3 I argue that, given semantic externalism, we cannot non-empirically know whether we have beliefs or are zombies. Section 4 spells out the consequences of this position for Putnam's and Dretske's anti-skeptical arguments.