Firstly, Descartes considers his senses. He says: “Everything that I accepted as being most true up to now I acquired from the senses or through the senses.”. Descartes goes on to doubt that we can trust the senses: “I have occasionally found that they deceive us, and it is prudent never to trust those who have deceived us, even if only once.” While most people can relate to the experience of being deceived by the senses, for example when a straight pencil seems to be bent when half emerged in water, however, I think the argumentation is invalid. The argument Descartes is making can be reconstructed in the following way: Because the senses sometimes deceive us, they may always deceive us. In itself the word ‘sometimes’ rules out that it always happens. In order for the senses to occasionally deceive us, there have to be occasions when they don’t deceive us. Therefore they cannot possibly always deceive us. Descartes’ method however, does not require belief-defeating doubt; only that we acknowledge that our beliefs are not sufficiently justified. All Descartes is saying is that we cannot know when we are deceived and when we are not. So for the sake of his project we have to assume that all beliefs we have acquired through the senses are untrue.
It is unlikely that I will doubt that at this moment I am sitting in a chair writing this essay, but I could be dreaming that I am sitting in a chair writing this essay. We think it is easy to distinguish whether we are dreaming or awake because we can perceive everything much more clearly and distinctly when awake. However, there have been times when I was dreaming but convinced that the dream was the reality and only after waking did I realize that it was in fact a dream. In a similar way I could right now be deceived into believing that I am awake while in truth I would be dreaming. Descartes says he can “never distinguish, by reliable signs, being awake from being asleep” and therefore never be certain whether he is awake or, in fact, dreaming. Norman Malcolm has argued against this argument that questioning the state of consciousness is only possible when a person is awake. In a dream state one would never doubt that it was a dream. Although it is very hard to prove or disprove this, many psychologists agree that when having a lucid dream people are known to have questioned their consciousness. Descartes however, is only concerned with the insufficient justification of the fact that we are not dreaming. By the same logic, as before with the senses, he concludes that we must assume that we are dreaming and everything we perceive is not true.
Now that it has been established that the senses are unreliable and must, at this point, be mistrusted, Descartes faces the fact that the rules of mathematics and geometry still hold true. Whether he is dreaming or awake, 2 + 3 is always equal to 5. At this point he argues that he could be deceived by a malicious, omniscient, omnipotent demon: “I will suppose that, not god who is the source of truth but some evil mind, who is all powerful and cunning has devoted all their energies into deceiving me”. This demon could be deceiving him into thinking that 2 + 3 equals 5 where in reality 2 + 3 is actually equal to 6.
At this point, in my opinion, Descartes’ method of sorting out rotten apples hits a dead end. The omnipotent demon could deceive us into thinking that we must mistrust our senses and believe that we are dreaming in order to find the foundation upon which we can base our beliefs. In other words the demon could have deceived us into thinking that emptying the basket will lead to us finding the fundamental truth. However, everything we obtain by doing what the demon has deceived us into doing cannot be accepted as the fundamental truth. This includes the “cogito ergo sum” which was found to be the only truth left after having doubted everything else. In the second mediation Descartes establishes that he exists, i.e. is a thing. He does this by using “I think, I exist” where the ‘I’ exists if it thinks and Descartes justifies that he thinks with the fact that he doubts. He says: “But what then am I? A thinking thing. And what is that? A thing which doubts, understands, affirms, denies, wills, does not will and which also imagines and senses.”. But if the doubting, understanding, affirming, denying, willing, imagining and sensing was a deception or the effect of a deception created by the demon then he is not thinking. If he is not thinking, he is not a thinking thing and thus does not exist.
The conclusion of such a line of reasoning would be that, what we think of as the ‘I’, that Descartes tries to prove exists, is in fact just a game the demon is playing. It is possible that we would have come to the right conclusion if we had not done what the evil demon deceived us into believing is the right path to finding truth. As long as there is such a demon however, we can never find the fundamental truth because it is impossible to get around his deception. Consequently, there could be some kind of fundamental truth which is just out of our sight and thus for us unobtainable or there could be no fundamental truth at all. Either way we cannot prove our own existence by the method of doubting everything because nothing remains. Therefore, by introducing the demon Descartes has defeated the purpose of his project. We see later that Descartes has realized that the evil demon is a flaw in his argumentation when he argues for the existence of a benevolent god in the third meditation. Thus he is contradicting what has played a crucial part to his argument up to that point.
Descartes has taken up a too radical approach to scepticism. While the sensory doubt and the dreaming hypothesis can be attacked they are and function well in serving the purpose of the project. However, when introducing the concept of the demon hypothesis, the search for a fundamental truth becomes unfeasible, as no belief can escape the possibility that it might be a deception created by the evil demon. This is where Descartes’ method of doubt meets its limitation. I think no method of doubt is without limitations so whenever a method of doubt is undertaken all limitations must be stated. Of course, any limitations in the meditations would render the project useless.
Bibliography
Adam, Charles & Tannery, Paul, Ouvres de Descartes, 1893
Descartes, René, Meditations and Other Metaphysical Writings, Penguin Classics, translated by Desmond Clarke, 2003
Warburton, Nigel, Philosophy: The Classics, Routledge, 2006
Adam & Tannery, Ouvres de Descartes, 7:481
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Warburton, Philosophy: The Classics, Routledge (48)
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