Poor Descartes, as I have remarked before, usually comes in for a ritual denunciation in books about consciousness, blamed for having espoused or even invented dualism, the doctrine of the separation of body and spirit. I think it would be more accurate to see him as presenting a new secular and rational perspective on the conception of the soul which was then prevalent (and to a considerable extent, still is); one which actually narrowed down its sphere of influence to the pineal gland. It seems perverse to me to suggest that later European thinkers got their dualism from Descartes rather than from the common Christian heritage, though that seems to be the way most people see it
But Descartes is relevant to the current debate about consciousness in other ways, too. In particular, I think his most famous argument, the ‘cogito’, challenges some currently-popular perspectives in a way which is well worth considering.
The cogito (‘cogito ergo sum’ – I think, therefore I am) is surely the most well-known argument in philosophy – it occupies the kind of place in its field which the Mona Lisa, Hamlet’s soliloquy, or Beethoven’s Fifth Symphony, occupy in theirs. This kind of mass popularity can, paradoxically become a barrier to proper appreciation. In order to draw out its importance for consciousness, I should like to focus on two points about it: first, it isn’t original; second, it isn’t logical.
Not original, because the same argument can actually be found in St Augustine. I don’t think anyone knows for sure whether Descartes found it there or came up with it independently, but the obvious question is – if St Augustine came up with it first, why aren’t we all talking about St Augustine’s cogito?
The reason, I think, is that the argument was of no great importance to St Augustine. He was in pursuit of faith, not doubt, and was more interested in God’s existence than his own. He puts no particular stress on the cogito argument, and readers who aren’t particularly looking out for it could easily read it without noticing its signficance. For Descartes, by contrast, everything depended on it. He needed a point of certainty from which to begin the construction of his metaphysics: St Augustine already had a source of certainty in God. Descartes also turned to God as a guarantor of knowledge, of course, but in his case, unprecedentedly, God did not come first. In this respect, modern philosophers are mostly in the same boat as Descartes, and if they want certainty, they have to undertake a similar exploration.
Not logical? I don’t, of course, mean that the cogito is illogical, or contains flawed reasoning. But the cogito is often interpreted as a piece of pure logic, an a priori argument whose truth does not depend on observation, like the truths of mathematics. This is a mistake.
Suppose the characters ‘2 + 2 = 4′ were to appear by chance in the pattern of clouds in the sky: the statement they represent would still be true. But if the clouds somehow lined up to form the words ‘cogito ergo sum’, it would be false – the clouds are not doing any thinking. Descartes is not offering a logical proof, but making a claim that certain kinds of perception, or thought, are immune from error. In particular, when I perceive my own existence, I cannot be wrong, because if I didn’t exist no perceiving would be going on. Even doubting my own existence actually proves it, because only entities which exist can doubt their own reality.
There may be just a few other perceptions which have a similar immunity from error. Arguably, you can’t be wrong about being in pain, for example, though you might be wrong about the existence of the dentist. But I digress…
The point here is that if you’re looking for philosophical certainty, and you can’t get it from God, it can only be found in the first-person view, and in the self. But the first-person view, and the reality of the self, are just what many modern thinkers about consciousness would want to do without. These days, we look to empirical science for the truth, and distrust our own inner phenomenal experience, although all our knowledge of the world, and of science, actually derives in the final analysis from interpretation of our own subjective phenomenal experiences (doesn’t it?).
It wasn’t always quite like this. In Brentano’s day it was natural to think that the business of psychology included the classification and study of one’s own inner, subjective sensations: but the disastrous over-development and subsequent collapse of introspectionist psychology functioned like a nuclear explosion, not merely destroying the existing structures, but rendering the whole territory of phenomenal experience uninhabitable and even unvisitable for a generation. During the era of Behaviourism, subjective experience and even consciousness itself was actually denied as a result. Those days have passed, but many still feel that if something can’t be investigated from the third-person point of view, it can’t be brought within respectable science at all.
I suppose this epitomises the dilemma of consciousness as it exists today: direct, first-person investigation of phenomenal experience seems to lead nowhere, but certain key aspects of consciousness – qualia, meaning, selfhood, and so on – seem to have no place in the objective third-person account.
Some, of course, are bold enough to offer eliminative accounts of these intractable phenomena: for them, the Cartesian suggestion that all knowledge ultimately springs from phenomenal experience must surely be profoundly unpalatable. Could this be one of the reasons why Descartes keeps getting such a drubbing?