Brain in a Vat

Time has been hard to come by recently, and this post will have to be brief. But my wonderful cousin Tracy, who is one of the very few people to ever visit this blog brought up Descartes' Brain in a Vat thought experiment a few weeks ago, and I want to say something about it.

I am certain that what I will say has nothing to do with what led her to bring it up, or the insight she had into the thought experiment. So I am really just expressing my own (half-baked) thoughts on the subject.

Distinguish between Tim and Tim*: one and the same person whom we imagine in two altogether different situations. Tim's situation is normal, like yours or mine. Tim*, however, is a brain in a vat. Suppose a mad scientist abducted and "envatted" Tim* by removing his brain from his skull and putting it in a vat in which his brain is kept alive. Next, the mad scientist connects the nerve endings of Tim*'s brain with wires to a machine that, controlled by a powerful computer, starts stimulating Tim*'s brain in such a way that Tim* does not notice what actually happened to him. He is going to have perfectly ordinary experiences, just like Tim. Indeed, let's assume that the mental states of Tim and the mental states of Tim* are alike. But, since Tim* is a brain in a vat, he is, unlike Tim, radically deceived about his actual situation. For example, when Tim believes he has hands, he is right. When Tim* believes he has hands, he is mistaken. (His hands were discarded, along with the rest of his limbs and torso.) When Tim believes he is drinking coffee, he is right. When Tim* believes he is drinking coffee, he is mistaken. (Brains don't drink coffee.) Now suppose Tim* asks himself whether he is justified in believing that he has hands. Since Tim* is just like Tim, Tim* will say that his belief is justified, just as Tim would if he were to ask himself whether he is justified in believing that he has hands. Evidentialism implies that Tim*'s answer is correct. For even though he is deceived about his external situation, he is not deceived about his evidence: the way things appear to him in his experiences. This illustrates the internality of evidentialist justification. Reliabilism, on the other hand, suggests that Tim*'s answer is incorrect. Tim*'s belief that he has hands originates in cognitive processes — "seeing" and "feeling" his (nonexisting) hands — that now yield virtually no true beliefs. To the extent that this implies their unreliability, the resulting beliefs are unjustified. Consequently, he is deceived not only about his external situation (his not having hands), but also about the justificational status of his belief that he has hands. This illustrates the externality of reliabilist justification.

-From the Stanford Encyclopedia of Philosophy's article on Epistemology 

So you can see, the experiment is meant to clarify between different types of knowledge, and how different methods of inquiry can yield different answers to the same question. Actually, the answers are the same, but since they mean different things, they appear to be different. But this isn't what I find interesting about the experiment. Well it is interesting. I just want to discuss something else. The thought experiment, in order to work, depends on mind/brain identity theory. That is, it depends on the idea that if we were deprived of everything but our brain, we could still be the same person. Our identity would not have substantially changed.

Now, epistemology was never my area of focus, so I could be wrong about everything that I am saying, even on an elementary level. But since part of the reason I write this blog is to build intellectual confidence, I am not going to sweat the likelihood that I am embarrassing myself. My hunch is, that if we were in fact deprived of all our bodies but the brain, despite an extremely advanced apparatus to simulate all sense data via nerve simulation, it is possible that we would lack consciousness. I am not saying that I do think this is what would happen, just that it is possible. Much of our brain isn't actually just our brain. Involuntary reflexes, for example, carry out partially independent of the brain, otherwise we could in fact render ourselves completely paralyzed by pinching the area at the top of our spine (just like in the beginning of Young Frankenstein). Also there is the conditioning that allows us to perform certain athletic activities, even play music on an instrument. I don't have to think about each and every muscle or movement when I play a fast piece of music. I depend on a carefully timed interaction between hand and mind that is achieved through practice, and talent. And the talent is at least partially based on physical proportions like the length of my fingers (or height, in the case of basketball players or swimmers). It is not easy to imagine the brain of Van Cliburn being able to play the piano just as well in someone else's body, despite all his knowledge and memory.

Now I am really getting out of my depth. But, the theories of Roger Penrose may in fact also confirm my hunch. According to Penrose, consciousness results from activity in chains of protein in our brains called microtubules, it depends on quantum mechanics (or we describe how it functions with quantum mechanics, I am unclear about this), and it is not computable. Thus, it cannot be simulated. If Penrose is right, then we may be able to tell for sure that we are not in The Matrix.

So, if our consciousness depends on more than just a brain, we can in fact have some basis for knowing whether or not we can rely on our experiences. But you can't really use theoretical constructs as evidence (I'm looking at you, Hegel), so I can't say for sure that I have evidence that proves I am not a brain in a vat. I can just say that if my consciousness is in part dependent on more than a brain, then if I am conscious, then I am more than just a brain in a vat. That's a lot of ifs.