Showtime at the Cartesian Theater? Vehicle externalism and dynamical explanations

Vehicle externalists hold that the physical substrate of mental states can sometimes extend beyond the brain into the body and environment. In a particular variation on vehicle externalism, Susan Hurley (1998) and Alva Noë (2004) have argued that perceptual states, states with phenomenal qualities, are among the mental states that can sometimes spread beyond the brain. Their vehicle externalism about perceptual states will be the main topic of this article. In particular, I will address three strong objections to their vehicle externalism, objections by Ned Block (2005), Jesse Prinz (2006), and Fred Adams & Ken Aizawa (2008). Though in some ways these objections appear disparate, I will argue that all of them depend on a crucial presupposition, one which Hurley, Noë, and their sympathizers should reject. This presupposition is that perceptual character is fixed by an instantaneous snapshot of neural states, a view that Hurley dubbed ‘temporal atomism.’ To put the presupposition in more familiar terms, all three objections are implicitly committed to something like Dennett’s Cartesian Theater (1991). In the first part of the article, I will discuss Hurley and Noë’s views, and include reasons why their views entail the rejection of the Cartesian Theater. In the next part of the article I will introduce the three objections and show how they presuppose something like a Cartesian Theater. I will also show that, if the Cartesian Theater is rejected, the objections all vanish. In the final part of the article I address the charge that Noë and Hurley confuse causation with constitution. This charge reveals a lack of appreciation for the way in which dynamical explanation motivates Hurley’s externalism.