In my post on the mind-body problem, I forgot to add at the end that actually there is a whole chapter in the book Alvin Plantinga (see a previous post) devoted to one aspect of Plantinga’s view of the mind-body problem. This chapter is by Peter van Inwagen and it’s online here. Van Inwagen critiques in this chapter Plantinga’s Replacement Argument for Substance Dualism.
But in searching for this chapter online, I came across a fascinating recording of Plantinga speaking at the University of Minnesota on Against Materialism on Dec. 6, 2002. In the first part of his talk he goes over in great convincing detail the type of argument against mind-body materialism presented by Thomas Nagel (see my post The Mind-Body Problem). I found it fun to listen to him: An abstraction becomes a real person and it’s a delightful and (relatively) easy to follow speech.
But what about this replacement argument for substance dualism? Basically it’s saying that all parts of the body can be replaced without affecting the thoughts going on at the time, in other words without disturbing the “continuous consciousness”. Amazing! This is a “thought experiment” of course, and van Inwagen devotes his entire chapter to disproving the “continuous consciousness” claim. I couldn’t find online Plantinga’s original proposal; I thought it was in his “Against Materialism” talk, but he doesn’t mention it there. There’s a good discussion of a similar proposal by Eccles here.