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Descartes 1

The third skeptical hypothesis: The evil demon

At one point in his career, Descartes thought that mathematics represented the foundation, in other words that which could not be called into question. Clearly there is a good deal to recommend this view. It is pretty difficult to doubt that 2 + 3 = 5, or that squares have four sides. But he came upon a way to call even this into question.

In 1635, about the time he was writing the Meditations, Descartes was in Paris. In Paris, the scandalous case of the devils of Loudon was being tried. A handsome monk named Father Grenadier had been accused by the nuns in the little town of Loudon, of having introduced devils into the nunnery who were having sexual relations with the nuns. This is probably a good illustration of the evils of celibacy. But the point for our purposes is that for his own reasons, Cardinal Richelieu, had the case brought to Paris and prosecuted there. The nuns were put on the witness stand and sworn to tell the truth. But how could they? They were, after all, supposed to be possessed by devils! Devils, notoriously, lie, so how could the nuns be believed? This fascinating legal problem was making its way through the Paris salons. Descartes may well have encountered the problem and generalized it. What if there was an evil demon attempting to deceive me about everything? This is Richard Popkin's suggestion about the origin of the famous evil demon hypothesis. Apart from the dramatic interest of the story of the devils of Loudon, the story also tells us that Descartes in proposing a malin genie or evil demon was operating entirely within the bounds of his culture. To us this may seem like a very off the wall hypothesis, but it was not that strange in 17th century France.

For those of us who find the Evil Demon hypothesis rather peculiar, it is worth remembering that there are modern descendants of it that fit our cultural context better and that we may then find more plausible. There is, for example, the evil neurophysiologist who has your Brain-in-a-Vat in a laboratory in Virginia! Your brain is kept alive by various nutrients in the vat, and stimulated from a giant super computer which monitors all its functions and stimulates it appropriately. You think you have been leading a normal life, you know who your parents are, where you live, what your name is, what your phone number is and so on. But all of this is false information. You are a brain in a vat! In fact you have been put in this Philosophy class in order to finally find out the truth about yourself. Yes, you really are a brain in a vat! I can tell you don't believe me. The measurements of cortical activity which the computer is making indicate that you don't believe me! The evil neurophysiologist is now rolling on the floor of his Virginia lab, doubled up in laughter, because now, even when you are told the truth about yourself, you don't believe it! It couldn't be better! Ha! Ha! Still, in certain ways, the old malin genie hypothesis is more elegant than its modern descendents. On the evil demon hypothesis, for example, it is possible to doubt the existence of the external material world altogether. This is not possible with the evil neurophysiologist hypothesis. Anyway, back to Descartes. Descartes, remarkably, finds a way to defeat the evil demon. Given how powerful the evil demon hypothesis is, this is a remarkable achievement.

Just as the dream hypothesis is introduced by another hypothesis which is related to it which Descartes does not accept, the evil demon hypothesis is introduced (at the end of Meditation I, by the consideration that while it is difficult to see how I could be deceived in thinking that 2 + 3 = 5, such a deception would surely be possible for an omnipotent God. But God is supposed to be good. Well, then, I will suppose, not that a good God is deceiving me, but rather "that there is an evil demon, supremely powerful and cunning, who works as hard as he can to deceive me!." (Pg. 4) Such a being can make it that sky, air, earth, color, shapes and sounds, hands, flesh, blood and senses do not really exist, and are all dreamed illusions the demon uses to deceive me! In this way, all of those truths which withstood the power of the dream hypothesis can be called into question. This brings us to the end of Meditation I and the beginning of Meditation II where Descartes picks up this skeptical hypothesis once again.

 

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