The hyperbolical doubt if the First Meditation is often taken for the epitome of skepticism.(1) Thus Myles Burnyeat, in his 1982 paper, "Idealism and Greek Philosophy: What Descartes Saw and Berkeley Missed," argues that Descartes goes further than the ancient skeptics in doubting the existence of his own body--a given of everyday experience they never doubted. Nor was "the existence of the external world," which was imperiled by the agency of the evil demon and has been recurrently questioned ever since, a major subject for doubt in the skeptical tradition.(2) Moreover, Burnyeat explains, Descartes was able to carry skepticism to this extreme because his doubt was merely methodological: it left his provisional rules of conduct intact while he was searching theoretically for a truth that would itself be in the first instance theoretical. Of course we should not forget that eventually, Descartes believed, the truth he was on the way to discovering would have excellent consequences for practice also, namely, in medicine, mechanics, and morality.(3) Meantime, however, Burnyeat is certainly correct in maintaining that Cartesian doubt was indeed insulated against practice--as Hume's doubt would eventually be also, confined as it was to his closet.(4) So Descartes, and other modern skeptics after him, could be as skeptical as you like, as skeptical as any one can be. The ancient skeptics could not go that far, Burnyeat argues, because it was daily life they were concerned with, not some purely theoretical gambit. Like the philosophers of other Hellenistic schools--though differently, of course--they were seeking peace of mind, and they wanted to eliminate those unnecessary questions about hidden things--causes or "ultimate" realities--that served to obstruct the state of mind they called "tranquillity." Merely methodologically, doubt can become much more radical, and it is that radicalization that, with the help of his demon, Descartes accomplishes.
As an account of the difference between Descartes' doubt and the devices of ancient skepticism--or its early modern inheritors, like Montaigne or Charron--Burnyeat's exposition is certainly correct in the letter, and, as far as the skeptical tradition goes, certainly illuminating. Without touching on the differences between recent interpreters of Pyrrho or Sextus, we can take as read the general interpretation of the tradition they all to some extent share.(5) Moreover we can see that Descartes was, in a sense, proceeding to a more radical, yet (or because) less than practical skeptical position.(6)
Descartes himself insists on this aspect of his method of doubt, for example, in his reply to the Fifth Objections. Gassendi has accused him of frivolity in the First Meditation doubt; Descartes replies that of course he recognizes the distinction between the actions of life and the investigation of the truth: only in the latter can one pursue doubt as far as he has done.(7) He has made the same point elsewhere, he insists: the reference is to the synopsis, where he had admitted that "no sane person" had ever really doubted, in practical terms, that there was a world, that people have bodies and so on.(8) Indeed, even for the less hyperbolical doubt of the Discourse he had been careful to distinguish between his philosophical enterprise and the tentative morality he followed while pursuing it.(9)
I shall return to tiffs passage in the Replies in another context. Meantime, however, I should remark that the same passage casts doubt on another aspect of Burnyeat's argument: namely, that Descartes himself understood the difference between his own skepticism and that of the tradition as historical scholars now interpret it. After distinguishing between the actions of life and the quest for truth, he continues: "for when it is a question of organizing one's life, it would, of course, be foolish not to trust the senses, and the sceptics who so neglected human affairs to the point where friends had to stop them falling off precipices deserved to be laughed at. …