Dreams in a Vat

Sa？etak Putnam’s semantic argument against the BIV hypothesis and Sosa’s argument against dream skepticism based on the imagination model of dreaming share some important structural features. In both cases the skeptical option is supposed to be excluded because preconditions of its intelligibility are not fulfilled (affirmation and belief in the dream scenario, thought and reference in the BIV scenario). Putnam’s reasoning is usually interpreted differently, as a classic case of deception, but this feature is not essential. I propose to interpret BIV’s utterances as cases of reference failure best captured by truth-value gaps. Both anti-skeptical strategies are then vulnerable to the same type of objections (how do we know what state we are in or how do we know what kind of language do we speak)