The Evil Demon Argument

I’m reading Janet Broughton’s Descartes’ Method of Doubt, and I was struck by how different Descartes seemed to me than he seems to mainstream Descartes interpreters. I’m assuming here that what Broughton takes for granted is generally accepted throughout contemporary Descartes scholarship, which seems like a decent principle.

The big difference is how much weight to give to the discussion of past failures at the start of Meditation One. Here is the Cottingham translation of the relevant passage.

Whatever I have up till now accepted as most true I have accepted either from the senses or through the senses. But from time to time I have found that the senses deceive, and it is prudent never to trust completely those who have deceived us even once.

I think Descartes is making, or at least proposing, the following argument.

  1. We cannot gain knowledge from any method that has deceived us once in the past.
  2. All our methods for forming beliefs have deceived us (at least) once in the past.
  1. So we have no knowledge.

I don’t think this argument is entirely contained in that paragraph. Perhaps some of the discussion of dreams is supposed to back up premise 1. But I do think the argument is entirely finished by the time the evil demon comes into the picture. As of course it must be, since we haven’t (as far as we know) been deceived by evil demons in the past, and this argument turns on errors we know we’ve made.

I have three opinions about the role of this argument in the Meditations, which I’ll state in increasing order of absurdity (or at least heterodoxy).

  1. The argument here is independent of the evil demon argument, so the evil demon argument is not the only sceptical argument Descartes makes.
  2. This argument, the argument from past failure, is the sceptical argument with which Descartes is primarily concerned.
  1. Descartes does not make what is commonly construed as The Evil Demon Argument. The evil demon enters the story not so Descartes can state a sceptical argument, but so we (and he) can appreciate the consequences of the sceptical argument that he has already made, namely the argument from prior error.

Perhaps the first of these points is widely held; I should finish the Broughton (and perhaps read other things) before commenting more. But I’m pretty sure 2 and 3 are not commonplace views. Still, I think they can make sense of several puzzling features of the text.

One of these puzzles, which Broughton mentions, is that Descartes never clearly expresses what is wrong with the Evil Demon argument. This would be odd if it was his key argument. But note that he does say what is wrong with the argument from past failure. Indeed, a centrepiece of the book is the argument that premise 2 of that argument fails, because the method Believe what you clearly and distinctly perceive has never led to failure.

I’ll say more about this when I finish Broughton’s book, but I thought I’d start by posting my quirky views, leaving the real arguments for them for later.

6 Replies to “The Evil Demon Argument”

  1. When I teach the First Meditation, I reconstruct the past failures argument like this:

    1. The senses have deceived us in the past.
    2. We should never trust those who have deceived us even once.
    3. We should never trust the senses.

    And I go on to say that, immediately after presenting this argument, Descartes himself points out that premise 2 is false. So I guess I agree with your 1 (besides the past failures and the evil demon argument, we also have, in the First Meditation, the argument from origins (I was either created by God or by lesser causes, and in either case I am liable to be radically deceived), the argument from madness (which Descartes also immediately discards, although for no clearly good reason) and, of course, the dreaming argument. I also agree with your 3, actually, except that, in my interpretation, the evil demon is a reminder of what the argument from origins (and not the argument from previous mistakes) taught us, and so I disagree with your 2.

  2. Juan,

    Why do you think Descartes takes himself to be pointing out that 2 is false? I should go back and check the original texts, but the Cottingham translation doesn’t suggest that reading. Here the relevant sentence.

    Yet although the senses deceive us with respect to objects which are very small or in the distance, there are many other beliefs about which doubt is quite impossible, though they are derived from the senses.

    I take that to be Descartes lamenting the fact that we can’t, as we should, doubt the fallible senses. To read it as a denial of your premise 2 you have to read the ‘impossible’ there as some kind of normative judgment. (As in, impossible to properly do.) But I don’t see why we should read it that way. One of the themes of Meditation One is that we aren’t very good doubters.

  3. Some of my reasons have to do with the flow of the First Meditation as a whole. Right after the passage you cite, Descartes goes on to briefly consider and reject the argument from madness, and then the dreaming argument, and I take it that the argument from sense-deception is left aside at that point. Some of my reasons, however, are extra textual and a mere application of the principle of charity. Premise 2 of the argument really is strikingly false, and its falsity even seems to be presupposed in claiming that we have evidence for 1.

  4. Also, this seems to be the interpretation of Cottingham in Descartes. I offer the following quotes not as an argument from authority, but just as indications of where I might have gotten my interpretation from.

    Referring to the argument from sense deception, Cottingham says:

    And a page later he says that “Indeed, [Descartes] explicitly asserts that, despite my experience that the senses sometimes deceive, there are many sense-based beliefs about which doubt seems quite unreasonable.”

  5. Brian,

    Of your three would-be heterodoxies, I believe that 1 and 3 are widely held. As I recall Broughton, she’d agree with them anyway. (As an aside, I doubt your strategy of presuming that Broughton’s reading is the orthodoxy.)

    2 seems false to me, because I do not think that there is a unique “the sceptical argument with which Descartes is primarily concerned.” The argument from madness/dreams and the argument from chance/poor design are distinct.

    None of that answers your claim that the argument from past failure is a further distinct argument— perhaps it is.

  6. For the not-very-much that it’s worth, I think Descartes in Med 1 is using (a) dreams and (b) the evil demon as heuristics for error-possibilities and hence dubitability. That is: If it could be a dream, it might be false; if it could be the product of a demon’s deception, it might be false; hence I will not trust it.

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