Brains in a VAT and memory: How (not) to respond to Putnam's argument

Abstract

Putnam's argument that we are not brains in a vat has recently seen a resurgence in interest. Although objections to it are legion, an emerging consensus seems to be that even if it successfully refutes one version of the brain in a vat scenario, lifelong envatment, it is powerless against a different one, recent envatment. Although initially appealing, I argue in this paper that this response-merely replacing lifelong envatment by recent envatment-is a bad response to Putnam's argument. Yet there is a different version of the brain in a vat scenario, recent memory-altering envatment, that Putnam's argument does not refute and is also sufficiently radical. The crucial issue turns out to be which epistemic sources sceptical scenarios may attack. I argue that there's no convincing reason for exempting memory from the sceptical attack: Sceptical scenarios must target memory to be sufficiently radical and they can do so without violating any constraint on sceptical scenarios. In the end Putnam's argument doesn't fail because of some 'deep' philosophical mistake, but because it overlooks how flexible and adjustable sceptical scenarios are.