There are two versions of Cartesian Dualism (that is, two forms of dualism that have been proposed by Descartes). The first is found in his work Discourse on the Method and relies on his ideas regarding doubt. The second – which is far more sophisticated – is found in his Meditations and is based around his ideas regarding clear and distinct perceptions, as outlined in the previous post. I’ll look at both here, discussing the first briefly and spending more time examining the second.
So, as said, the first relies on doubt. Decartes’ argument runs like this; he can doubt his body quite easily (that is, he can imagine that it doesn’t actually exist), whereas the same is not true of his mind, due to the Cogito. It would be absurd for him to claim that his mind doesn’t exist, as this would mean he doesn’t exist – and if he didn’t exist he wouldn’t be capable of claiming anything. He concludes from this that his mind and body are two distinct entities. But there’s a fatal flaw to this argument. The problem is that it’s possible to doubt that something is true even though it is. For instance, I might doubt that it’s snowing outside, then look out of a window and find that it is. Likewise, the fact that I can doubt that my body exists, does not mean that it really doesn’t.
Descartes responded to this objection in his meditations by formulating a new kind of dualism. Here, he relies on his “truth criterion”; that we must perceive something clearly and distinctly in order for it to be true. Related to this is his conviction that what we clearly and distinctly perceive to be the essence of something must be the true essence of that thing, thanks to the benevolence of God, who would not wish us to be deceived about such things. His argument in this case, then, runs thusly; he can perceive his mind very clearly and distinctly, the same not being true of his body. He also perceives the essence of his mind to be that of thought, whereas the essence of the body – like all physical objects – is extension. Therefore, he concludes, he can see his mind as something distinct from his body and capable of existing independently of it.
Descartes also made some attempt to show the nature of the mind as opposed to the body, whilst also speaking about the relationship between the two. Primarily, Descartes asserts that the mind is something indivisible, whereas this is not true of the body. We can chop off pieces of the body quite readily – it has been done many times in the past. Indeed, pieces of the body fall off rather frequently. The mind, however, is not a physical thing. It is an immaterial singularity, and we can’t really speak about people having “half a mind”. Also, when we remove parts of the body, the mind remains intact. This, again, implies that the two are separate and independent of each other. What, then, is the relationship between the two? Clearly it’s not the same as the relationship between a person and their home. If I were to see that my house was damaged somehow, I’d be concerned but I wouldn’t experience any mental discomfort (besides worrying about the cost of repairing it). But when my body’s damaged I feel pain. Clearly, then, the relationship between mind and body is very intimate.
There are a number of objections that can be raised against Decartes’ arguments here. For instance, as far as the essences of mind and body being different is concerned, how can we be sure that we’re correct in thinking we know the essence of these two properly? Example: a person might not be aware of the fact that white light is a combination of all the wavelengths of visible light (green, blue, and red light). Being unaware of this fact, the person in question would not think that it has anything to do with the essence of white light, even though it obviously is. White light is, in essence, a combination of red, blue and green light (any sciency person reading this may feel free to correct me – I wouldn’t call this my “area of expertise”). The same may be true of the mind, or even the body. Furthermore, is the mind really indivisible? These days it’s actually quite common to view the mind as consisting of several things; emotion, logic, creativity, and so on and so forth. When looked at in this manner, it’s not so unreasonable to think of dividing it. Also, what of the brain? It could be argued that when we take away pieces of the brain (which is a part of the body), the mind is affected. And what of the relationship between the two? We already know it’s very intimate, a fact Descartes agrees with, but this seems to conflict with the idea that they are separate and distinct. Besides this, how would it be possible for an immaterial, thinking thing to interact with and control a physical body? The two seem incompatible, and yet this is precisely what the mind does.
This, then, is Cartesian dualism in a nutshell. Note that, besides the objections I just raised, Decartes’ entire second argument fails completely if we do not believe in God’s existence.
- Descartes’ Concept of Self (poignantboy.wordpress.com)
- Decartes’ Meditations on First Philosophy – Cartesian Skepticism (poignantboy.wordpress.com)