Descartes's Dream Argument

Descartes’s Dream Argument

This would all be well and good, were I not a man who is accustomed to sleeping at night, and to experiencing in my dreams the very same things, or now and then even less plausible ones, as these insane people do when they are awake. How often does my evening slumber persuade me of such ordinary things as these: that I am here, clothed in my dressing gown, seated next to the fireplace – when in fact I am lying undressed in bed! But right now my eyes are certainly wide awake when I gaze upon this sheet of paper. This head which I am shaking is not heavy with sleep. I extend this hand consciously and deliberately, and I feel it. Such things would not be so distinct for someone who is asleep. As if I did not recall
having been deceived on other occasions even by similar thoughts in my dreams! As I consider these matters more carefully, I see so plainly that there are no definitive signs by which to distinguish being awake from being asleep. As a result, I am becoming quite dizzy, and this dizziness nearly convinces me that I am asleep. – Meditation I, p. 28a-b

-Does Descartes, in his dream argument, rely on “facts about dreaming” – like that we often dream, that our dream experiences are often very vivid, etc.?

-No: Barry Stroud (The Significance of Philosophical Scepticism):

When he first introduces the possibility that he might be dreaming Descartes seems to be relying on some knowledge about how things are or were in the world around him.
He says, “I remind myself that on many occasions I have in sleep been deceived by similar illusions,” so he seems to be relying on some knowledge to the effect that he has actually dreamt in the past and that he remembers having been “deceived” by those dreams. That is more than he actually needs for his reflections about knowledge to have the force he thinks they have. He does not need to support his judgement that he has actually dreamt in the past. The only thought he needs is that is now possible for him to be dreaming that he is sitting by the fire, and that if that possibility were realized he would not know that he is sitting by the fire. Of course it was no doubt true that Descartes had dreamt in the past and that his knowledge that he had done so was partly what he was going on in acknowledging the possibility of his dreaming on this particular occasion. But neither the fact of past dreams nor knowledge of their actual occurrence would seem to be strictly required in order to grant what Descartes relies on – the possibility of dreaming, and the absence of knowledge if that possibility were realized. (p. 17)

-Yes: E.M. Curley (Descartes Against the Skeptics): Step in Curley’s reconstruction of Descartes’ argument:

(2) Sometimes I have, in dreams, experiences which I take to be of ordinary-sized
objects in my immediate vicinity and which are so like my most vivid waking experiences that they are not, in themselves, certainly distinguishable from the waking experiences. (p. 56)

-Does Descartes get the “facts about dreaming” right?
-No: J.L. Austin (Sense and Sensibilia):

Another erroneous principle which the argument here seems to rely on is this: that it must be the case that “delusive and veridical experiences” are not (as such) “qualitatively” or “intrinsically” distinguishable – for if they were distinguishable, we should never be “deluded”. But of course, this is not so. From the fact that I am sometimes “deluded”, mistaken, taken in through failing to distinguish A from B, it does not follow that A and B must be indistinguishable. Perhaps I should have noticed the difference if I had been more careful or attentive…” (p. 51)

I may have the experience … of dreaming that I am being presented to the Pope. Could it be seriously suggested that having this dream is “qualitatively indistinguishable” from actually being presented to the Pope? Quite obviously not. After all, we have the phrase “a dream-like quality”; some waking experiences are said to have this dream-like quality, and some artists and writers occasionally try to impart it, usually with scant success, to their works. But of course, if the fact here alleged were a fact, the phrase would be perfectly meaningless, because applicable to everything. (p.
48)

We all know that dreams are throughout unlike waking experiences. (p. 42)

-Yes: Curley: Cites research (reported in W. Dement, “An Essay on Dreams,” in New Directions in Psychology, II):

The physiological data describe a central nervous system that is, in fact, behaving as if it were receiving a high level of sensory input from the environment … its neurophysiological properties resemble those of the active waking state

[REM mental activity is] not only more complex [than non-REM mental activity occurring in sleep], but presents an essentially complete perceptual field … just as in the waking state, all sensory modalities are ordinarily present in the dream … with many details in each mode. (quoted at pp. 63-64 of Curly)

Descartes, escaping from the Dream Argument?:

The hyperbolic doubts of the last few days ought to be rejected as ludicrous. This goes especially for the chief reason for doubting, which dealt with my failure to distinguish being asleep from being awake. For I now notice that there is a considerable difference between these two; dreams are never joined by the memory with all the other actions of life, as is the case with those actions that occur when one is awake. For surely, if, while I am awake, someone were suddenly to appear to me and then immediately disappear, as occurs in dreams, so that I see neither where he came from or where he went, it is not without reason that I would judge him to be a ghost or a phantom conjured up in my brain, rather than a true man. But when these things happen, and I notice distinctly where they come from, where they are now, and when they come to me, and when I connect my perception of them without interruption with the whole rest of my life, I am clearly certain that these perceptions have happened to me not while I was dreaming but while I was awake. Nor ought I have even the slightest doubt regarding the truth of these things, if, having mustered all the senses, in addition to my memory and my intellect, in order to examine them, nothing is passed on to me by one of these sources that conflicts with the others. For from the fact that God is no deceiver, it follows that I am in no way mistaken in these matters. .
– Meditation VI, pp. 54b-55b