Abstract

This chapter is a relatively self-standing essay that takes up how we should best understand the famous ‘brains in vats’ (BIV) thought experiment and relates it to the ideas of Chaps. 3 and 4. Hilary Putnam, another central neo-pragmatist philosopher, argued we cannot be brains in vats (at least, eternally so) and used this result as part of his argument against a view he called ‘metaphysical realism’ (MR): the idea that there an absolute reality consisting of mind-independent objects, properties, relations, structures etc. with a wholly determinate nature which set the ultimate standard for our cognitive practices. I have previously argued in Chaps. 1 and 2 that MR falls along with what Price calls Representationalism, and for similar reasons to Putnam’s so-called ‘model-theoretic’ arguments; hence I am also broadly sympathetic with Putnam’s BIV argument, at least understood as a reductio of MR. In this chapter I present Tim Button’s recent defence of Putnam’s arguments against MR, but also critique how he responds to them. I then consider and defend David Chalmers’ view that the BIV scenario (or Matrix scenario, or simulation hypothesis) is, contra Putnam and Button, epistemically possible, but does not threaten our everyday knowledge. I finally consider what I call, following Hubert Dreyfus, the ‘existential phenomenological take’ on the BIV thought experiment which I suggest involves an improvement on Chalmers’ view, and can be seen as cohering with the idea behind PE that we must draw a distinction between the experiential world for us and the world in itself.