Journal of the History of Ideas

In making his case for skepticism, Peter Unger offers the following exotic case as one which “conforms to a familiar, if not often explicitly artic-ulated pattern or form” of skeptical reasoning: ¹ imagine that there is an evil scientist who deceives subjects into falsely believing that there are rocks. Living in a world bereft of rocks, he induces belief in their existence using electrodes implanted into the appropriate parts of the subjects’ brai ns, protoplasm, or systems through which he sends patterns of electrical impulses in accord with his deceptive designs. Unger then offers the following argument, which is supposed to instantiate the pattern or form of this kind of skeptical reasoning:

If you know that there are rocks, then you can know that there is no such scientist doing this to you. But no one can ever know that there is no evil scientist who is, by means of electrodes, deceiving him into falsely believing there to be rocks. So ... you never know that there are rocks. But of course we have chosen our person, and the matter of there being rocks, quite arbitrarily, and this argument ... may be generalized to cover any external matter at all. From this, we may conclude ... that nobody knows anything about the external world. ²

After presenting this case and articulating its form, Unger claims that “this argument is the same in form as the ‘evil demon’ argument in Descartes’s [End Page 109] Meditations; it is but a more modern, scientific counter-part, with its domain of application confined to matters concerning the external world.” He then proceeds to describe Descartes’s argument as “the most compelling sceptical argument the phil osophical literature has to offer,” calling it in fact “the classical argument for scepticism.” ³

These claims may seem a little bit surprising; for it is not obvious, even from the most careful attention to the text, that what is written about the evil demon in the First Meditation constitutes a skeptical argument at all, and the scholarly literature is generally, and perhaps surprisingly, quite confusing about just what is going on at the end of the First Meditation. Further, rather than being exceedingly compelling as Unger thinks, arguments of this form are not only assiduously avoided by Descarte s during his descent into skepticism but are in fact, as I shall argue with some help from Descartes, weak and considerably less compelling than the kind of skeptical challenges Descartes actually offers.

My purpose in this paper, then, is to make two related points, one historical and the other philosophical. First, I will try to demonstrate, on the basis of both textual and critical evidence, that Descartes was not offering a (further and final) skeptica l argument when he invented his demon. I will try to exhibit some of the confusions in the scholarly literature about the text of the last three paragraphs of the First Meditation and, by so doing, support Gouhier’s position that the idea of the demon “ha s no metaphysical significance; it is purely a methodological artifice which permits doubt to continue....” ⁴ Second, I will show that embodied in Descartes’s rejection of this kind of skeptical reasoning is the very reason for its weakness, a weakness that should prevent it from being considered, as Unger considers it, the classical form of skeptical argument. The inventions of the First Meditation still exercise considerable hold on our philosophical imaginations. I hope to show that, at least as far as the demon is concerned, Descartes would have been surprised at some of the most conventional and entrenched scholarly interpretations given his use of it and not at all sympathetic to its employment in a skeptical argument. Lest the demon seem an old and tired subject of philosophical scrutiny, let me beg the reader’s indulgence by promising both a deeper than usual look into the text of the end of the First Meditation and some significant conclusions about Cartesian skepticism that are hardly commonplace and thus neither old nor tired. [End Page 110]