Descartes' Dualism: Correcting Some Misconceptions

[T]hose who do not bother to grasp the proper order of my arguments and the connection between them, but merely try to quarrel with individual passages, will not get much benefit from the book. (Descartes [AT VII 379])

For the greater part of this century, philosophy has relegated Descartes to the rôle of anti-hero, with philosophers defining their positions against "what are seen as deeply flawed Cartesian paradigms." ¹ This stance is succinctly captured in a recent paper by Bernard Williams:

[Descartes'] works (or a few of them) are read (or partly read) as the most challenging and informative misleading example of what is to be rejected [. . .] He is typically presented [. . .] as one who simply had a weakness for scepticism, or perhaps for mathematical certainty [. . .] or whatever misconception particularly impresses the teacher as providing the source of scepticism: a student will reasonably conclude, not only that Descartes is a fool, [. . .] but more damagingly, that a subject which [. . .] thinks it important that one should now read [his] works [. . .] cannot be a very serious subject.²

If having a weakness for scepticism has been seen as one flaw in Descartes, having a weakness for dualism has undoubtedly been seen as another; my concern here is solely with the latter. My primary focus is on the claim (which I call the standard claim), ³ that Descartes based his dualism on a fallacious argument found in the Discourse Part IV (AT VI 32-33 ⁴) which involves a move from what he can or cannot doubt to a metaphysical conclusion. This argument is standardly referred to as the argument from doubt.

This is not the first investigation into the Discourse argument, but the major problem with previous examinations of the argument is their approach: the examinations and reformulations are not of Descartes' argument but of Arnauld's version of it, which has been seen as involving a fallacious application of Leibniz's principle. Inevitably the results tend to fall in line with the general consensus: even if the argument from doubt (however reformulated) is not Descartes' only argument for dualism, it is one of them, and it is fallacious. ⁵ The approach I adopt here is different since my main concern is not with yet another reformulation of Arnauld's version of the argument, but with a critical examination of the standard claim itself. I contend that the standard claim derives its force mainly from a number of misconceptions of Descartes' arguments; it derives its persistence largely from a general acceptance of an anti-dualist paradigm—the adoption of the "dogmatic rule that dualism is to be avoided at all cost"' ⁶ and the assumption that physicalism is true: "Many philosophers do not give any arguments for physicalism, but take some such position for granted in all their reasonings." ⁷ Paul Churchland, for instance, claims that our conception of mental phenomena "constitutes a radically false theory, a theory so fundamentally defective that both the principles and the ontology of that theory will eventually be displaced." ⁸ One asks (with David Ross), if reason has made such an egregious error about itself, what is it that reassures Churchland that reason can be trusted in its power to know anything at all? ⁹

My central task is two-fold: (a) to argue that correcting the misconceptions shows that the Discourse argument is not only immune to the standard claim, but is in fact not an argument from doubt at all—indeed, there is no argument in Descartes, much less the argument for dualism, which is established on the basis of doubt, or of ignorance—and (b) to show that the Discourse argument is not an argument for dualism. As a result of examining the standard claim, further objections come into focus, but given the scope of this paper I deal with only some of them; ¹⁰ in particular I do not discuss the most controversial one, the incorporeality objection, since...