I want to write about dualism and where the mind-body problem comes from. There are many different ways to think about dualism, but Descartes’ way was two-way interactionist dualism. He didn’t even agree that there was a mind-body problem, let alone find it or make it up. He wrote in one of the Replies to Objections, “The whole problem in such questions comes from a false assumption that can’t be proven, namely, that if the soul and the body are made of different things, they can’t affect each other.” [My emphasis]. Descartes’ real job was to describe the mind and the body so well in terms of their “principal attributes” that his smarter readers, like Princess Elisabeth of Bohemia and Gassendi, were forced to think about the mind-body problem. They should get credit for figuring out how the mind and body work together. But Descartes should get a part of their Nobel Prize (or maybe the Tang Prize, since gunpowder was invented during the Tang Dynasty, while Nobel’s invention, dynamite, is a high explosive), since he laid the groundwork with his precise descriptions of the important parts: linear extension and consciousness. But Elisabeth could then write, “You completely leave extension out of your idea of soul.” The problem was that something that doesn’t live in the world of linear extension can’t interact with it, because interaction involves effects (“propulsion”) or the transfer of energy, which in turn requires contact, which requires a spatial location and therefore extension. There is also the question of how something that doesn’t have linear extension can leave its mark on something that does. It’s important to note that gravity has a place and a length; there’s a lot of it between the Earth and the Sun, and it gets weaker as you move away from big bodies. So, by Descartes’s rule, gravity is a physical force.
I’ve always liked dualism, but it doesn’t work for many of the same reasons that Elisabeth and Gassendi gave. Today’s dualisms, like E.J. Lowe’s, just hide the problem. But there it is, waiting for the unwary, even those “who have grown up with computers,” as David Duffy pointed out in his Comment yesterday. People who think this way might be tempted by the fact that computers exist to think that the mind-body problem can be solved by comparing the mind to the software and the brain to the hardware. The problem is that, even though the program is computational, it is purely physical in Descartes’s sense, despite what the early functionalists and the artificial intelligence community of today say. Even Stockfish, which has a rating of 3378 (Magnus Carlsen’s is 2802), can’t yet think, even about chess, in any interesting way other than “compute.”
I think one of the reasons I like dualism is that it keeps the difference between the mental and the physical. There is a big difference between saying that something is red and saying that it reflects light with a dominant wavelength of 6.5 x 10-5 cms. There really is a big difference. And these kinds of differences seem to stay the same, no matter how people look. It doesn’t have to be dominant frequency, which is a psychological concept anyway. It could be about how they act. But all of these descriptions fit with the idea that there is no red. You could have something that made them happy, but there wouldn’t be any red in it. So far, so good, but this is just a claim about phenomenal properties, like colors, sounds, heat, and so on. Some philosophers, call the phenomenal properties “qualia,” but others reserve the term for the properties of experience itself. For example, it is false that apples are red, but it is true that experiences are. We have here something that doesn’t help much with the mind-body challenge, except that our answer to the mind-body problem must respect the difference between the physical and the phenomenal.
On the other hand, it’s hard to believe in the different kinds of dualism. Interactionist dualism doesn’t give a good explanation of interaction, of all things! This is where the philosophers who came after Descartes realized that, even though he did a lot of good work, he got some things wrong. So, this group of philosophers, who still believed in dualism, tried non-interactionist ideas like occasionalism and pre-established harmony. I think there is a type of dualism that doesn’t get enough attention. I’m not sure what to call it, but “correlationism” comes to mind. If, for example, certain neurons in the visual cortex fire, you might feel red. When one set of events happens, the other set happens next. I guess this is a form of interactionism, but the idea of cause and effect is really pared down to its Humean basics. It would be easy to write it with INUS conditions, and the story would still make sense. I think it’s hard to figure out why this kind of thing (the firing of neurons) should lead to this kind of experience (the sensation of red). The connection between mind and body is still hard to explain, and this is the problem of dualism rearing its head again in a darker way.