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Descartes 1

The Dream Hypothesis

How could one doubt that one is sitting in a room, looking at a piece of paper? Descartes, sitting by the fire, begins by thinking about madmen. He says:

And on what grounds might I deny that my hands and the other parts of my body exist? -- unless perhaps I liken myself to madmen whose brains are so rattled by persistent vapors of melancholy that they are sure they are kings when in fact they are paupers, or that they wear purple robes when in fact they are naked, or that their heads are clay, or that they are gourds, or made of glass.

This reference to madness forcefully makes the point that it is difficult to doubt things which we perceive near us. Must we imagine ourselves mad in order to do so? In fact, Descartes dismisses the possibility that he is mad. He dismisses this, one might imagine, because he has no trouble distinguishing between the sane and the insane, and he thinks it would be mad to apply what he says about the insane to himself. Still, there is an element of the life of the sane which in some ways resembles the delusions of the insane -- the experience we have of dreams when we are asleep. Descartes is perfectly willing to contemplate this possibility. He says:

...if I weren't a man accustomed to sleeping at night whose experiences while asleep where at least as far-fetched as those that madmen have while awake. How often, at night, I've been convinced that I was here, sitting before the fire, wearing my dressing gown, when in fact I was undressed and between the covers of my bed.

On the hypothesis it appears that one could doubt things close at hand, even that I am now sitting by the fire, wearing my dressing gown! Here is the basis for a skeptical argument. It goes like this:

  1. I am sitting here in my study by the fire, in my dressing gown. (Knowledge claim)
    Presumably this claim is supported by strong evidence -- I see the fire, my dressing gown, I can feel the heat of the fire, etc.
  2. I am in bed with no clothes on. (Skeptical counter-claim to 1.)
    This too is supported by evidence -- I might be dreaming that I am in the study. This has happened to me many times before.
  3. 1 and 2 cannot both be true. (By the principle that reality is determinate.)
  4. One cannot determine which claim is true.
    If there is a genuine possibility that 1. might be false, Descartes must set aside his knowledge claim as dubious. This is a weaker requirement than that which the typical skeptic demands, i.e. that the evidence be equally balanced.)


5. So, we should suspend judgment as to whether 1. or 2. is true.

One might object to 5. by saying that surely one knows that one is awake, and so that 1. is true and 2. is false.

A realistic representation
of a woman
But, at least at this point, Descartes rejects this claim. He says: "When I think very carefully about this I see so plainly that there are no reliable signs by which I can distinguish sleeping from waking that I am stupefied - and my stupor itself suggests that I am asleep!" (Pg. 2)

Descartes then goes on to suggest that we might think of dreams as representations like paintings. Now there are realistic paintings which aim to represent the waking world faithfully. Here, by the way, is where we get the transition from the senses to the imagination. There is an important overlap. The image in the realistic painting might be something you would 'see' either while you are awake or in a dream, such as the fire in the fireplace or the woman represented here. It is because of this overlap that Descartes can use images from the imagination to raise doubts about the senses. Then there are Picaso or Salvador Dali paintings where the world is transformed by the imagination. Still, if you think about realistic paintings or even Dali paintings, it is likely that these images must have been patterned after real things. A dripping clock is an imaginary object, but it is still patterned after a clock.
Detail of a painting
by Salvador Dali
Or if you imagine the distortion of the painting becoming very severe, to the level of a cubist Picasso or Mondrian who paints rectangles, at least some simpler and more universal things are real. Descartes found that he could doubt that he was sitting by the fire in his dressing gown and so on. What he noted was that he could not doubt that these images were composed of real colors and shapes, the natures of numbers and figures and space and time.
Composition with Red,
Yellow and Blue,
Piet Mondrian 1921
This painting by Mondrian, which employs simple geometrical shapes and primary colors is probably more abstract than anything found in dreams. But it gives us a visual image of the direction in which Descartes is moving.

There is, in what Descartes is doing here, really two methods at work simultaneously. One is the method of doubt. This is proposing various skeptical hypotheses to separate what can from what cannot be doubted. As the skeptical hypotheses become more powerful, what could not be doubted on the previous hypothesis is called into question by a new and more powerful skeptical hypothesis. The second method is the method of analysis.


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