Before Descartes could even begin to structure his argument around his view of the mind he had to literally wipe the slate clean of everything he believed beforehand. He wanted to ensure that he would only be dealing in certain absolutely true facts. To do this he followed a couple of Greek examples, firstly Euclid’s book on geometry the Thirteen Elements, here Euclid uses absolute definitions to explain certain facts, Euclid (1956), p.155) “if equals be added to equals, the wholes are equal”, and Archimedes, Descartes (Haldane and Ross 1931, cited in Wilkinson, 2002), p.160) “in order that he might draw the celestial globe out of its place, and transport it elsewhere, demanded only that one point should be fixed an immovable.” By categorically stating the method for his arguments Descartes was attempting to ensure that no stone would be left unturned when constructing his mind body argument.
For Descartes to un-assume that he existed (for this was his starting point) he had to start by stating that he didn’t exist, to do this he came up with the theory that he had an evil genius that tricked him into assuming that he and the heavens and earth only existed in his imagination. But then he came to the realisation that for him to think that an evil genius existed, then he must also exist, because he thought, and to Descartes to think is to exist - cogito ergo sum.
Even though Descartes wanted to ensure that the facts were stated absolutely, he did have a tendency to miss out certain premises, creating enthymematic arguments, this was due to his reliance on his reader’s axiomatic belief, for example Descartes cogito, here Descartes says I think, then I exist, but this according to Thomas Hobbes causes a dilemma, because what Hobbes says in his objections, Hobbes, (Haldane and Ross 1931, cited in Wilkinson, 2002), p.29) “…it is not by another thought that I infer what I think… we cannot think that we are thinking… For this would entail the repetition of the question an infinite number of times…” Because of these fallacies in Descartes initial premises already we can see that his conclusions are on unsteady ground.
What Descartes is leading up to is that the mind and the body are two different types of substance, Wilkinson, (2002), p.37) “ The mind is mental substance, a continuously existing subject of experiences which exist in time but not in space, and whose essence is thought. The material universe, the universe of bodies, is composed of material substance whose essence is extension.” But just because the mind and body are two different kinds of substance doesn’t mean that they can’t coexist. The next step in Descartes argument is to explain how these two different substances coexist.
To argue how the two substances are different Descartes uses the argument that the mind is not divisible, but the body is divisible. To explain this argument Descartes explains that when a body loses a limb, it has actually lost a limb, there is still no loss taking place with the mind. This brings us around once again to extension. Descartes is arguing that the mind is not extended, but the body is extended, hence it is divisible. The mind according to Descartes is the substance that makes him aware that he exists; this is his conclusion from his cogito. He then goes on to add a premise that nothing else pertains to his essence except thinking, and it is here that he once again states his argument as an enthymeme. Here an objection is raised by one of Descartes contemporaries Antoine Arnauld, where he argues, Arnauld (Haldane and Ross 1931, cited in Wilkinson, 2002), p.44) “The problem is: how it follows, from the fact that one is unaware that anything else belongs to one’s essence, that nothing else really belongs to one’s essence.” What we are starting to see here is the way in which Descartes is manipulating his argument to fit his purpose. Because what Arnauld is saying and what many other philosophers have said is, how can we know that nothing else pertains to our essence except thinking, for all we know there may be lots of other things which pertain to our essence. This naturally causes most of the conclusions to break down. To depend on invalid premises in an argument, shows that the developing argument will be unsound.
Descartes whole argument really gains ground once he has stated that “I am a thing which thinks” – sum res cogitans. It seems like once he has jumped this hurdle all his other premises will fit smoothly into place, but we are finding that they won’t. Immanuel Kant in his first edition of his Critique of Pure Reason (1781) objects to Descartes argument because he argues that Descartes is assuming and not proving that there is only one I. Kant is arguing that there could be more than one I, and each I with its own illusory memories. He argues that Descartes hasn’t proved categorically that only one I exists, and that all he has proved is that something sometimes thinks.
So Descartes has concluded so far that he is sum res cogitants, or to be more precise his mind is sum res cogitants. He still hasn’t explained how this mind interacts (if it does at all) with the body. This is the next step of his argument.
Up to now Descartes is still imagining that his mind is in space, it exists because it thinks. He now construes a way of bringing about his body to also exist. He does this by explaining his imagination. With imagination he means things which he sees in his minds eye, and what Descartes discovered whilst looking through his minds eye, was that things were different to how they actually were: i.e. things he imagined were some times not as they actually were when visualized. For example the picture in your minds eye of an Alison Kirk Chrysanthemum, is quite different from the actual Alison Kirk Chrysanthemum, this is because in your minds eye there is know way of visualising all the many petals which the chrysanthemum possesses. What this made Descartes believe was that there must actually be a real object, because otherwise he would have imagined the real object exactly as it is in his minds eye.
So now Descartes mind has a body, but how do the two interact? We are still remembering that these two substances are different. Descartes explains it by saying the mind is like a pilot in the body’s vessel (this is a little like Stephen Dawkins ‘Survival Machines’ (Dawkins, (1976), pp.14ff), where genes use Gigantic Lumbering Robots (ibid., p.21) as vassals). This is because the mind does feel what the body feels; when the body stubs its toe the mind feels this also. So even though these two substances are different they intercommunicate with each other, how does Descartes explain this? He argues that in the brain there is a gland (we now know to be the pineal gland) which receives data from the animal spirits from the body which then (through this gland) passes the data to the mind. Here we find Descartes on very weak ground. This theory of intercommunication between the mind and the body was never really explained by Descartes and even when asked later in his life by Burman about the affect of the soul on the body and vice versa, Descartes replied, (Cottingham, cited in Wilkinson, 2002), p.50) “This is very difficult to explain; but here our experience is sufficient, since it is clear on this point that it is just cannot be gainsaid. This is evident in the case of feelings and so on.” I totally agree with Leibniz here when he states, Leibniz, (Leibniz, New System etc, cited in Wilkinson, 2002), p.50) “Descartes had given up the game on that point, so far as we can know from his writings.”
There are of course objections to the pineal gland theory but before I go to them I would like to sum up Descartes view of the mind by Cartesian Dualism. We are made up of mental substance and material substance, a substance doesn’t need anything else to exist, a substance is made-up of qualities, qualities have to be qualities of something, they don’t exist on their own. A mental substances essence is thought, whereas a material substance is extension. Mental substance exists in time only and not space, whereas material substance exists in both time and space.
We now have a clear view of Descartes view of the mind and how it communicates with the body, but of course there are objections, firstly regarding the pineal gland. Pierre Gassendi in his objections V, (Haldane and Ross 1931, cited in Wilkinson, 2002), p.49) “…we cannot grasp how you impress a motion upon [the animal spirits] …unless you really are a body …How can there be contact apart from the body, when (as is so clear by the natural light) ‘Apart from body, naught touches or is touched’.” This is clearly correct as Descartes states himself that the two parts (substances) are spatial and non spatial, which means they simply can’t, or shouldn’t be able to interact.
So we have three strong objections to Descartes view of the mind, these are: the mind body interaction, which we have discussed above and covers the causation of the mind to the body and vice versa; the negative characterization of mental substance, this is according to Descartes that mental substance does not exist in space; the unity of mind and body, where I explained through the pineal gland example.
These objections pick-up on Descartes ability brush over important aspects of his argument, because of this the argument not only misses premises, but because of this it therefore creates unsound conclusions.
Therefore to answer the initial question: ‘is Descartes’ view of the mind correct?’ I am inclined with the evidence I have assembled with clearly stated objections made by Hobbes, Kant, Gissendi, Arnauld &c, to the premises and conclusions within his argument, and due to the lack of neuroscience available to Descartes in the 17th century, that Descartes’ view of the mind is not correct. But, and this is important, I am not stating that his contemporaries are correct, because to this day we are still unaware of how, exactly, the mind does work.
Euclid, (1956), 2nd edition, The Thirteen Books of the Elements, Dover Publications.
Haldane, E.S. & Ross G.R.T. (1931) The Philosophical Works of Descartes, 2 vols, Cambridge University Press. Corrected edition.
Wilkinson, R. (2002) Minds and Bodies, The open University, Alden Press.
Dawkins, R, (1976) The Selfish Gene, Oxford University Press.