Jean-Luc Marion. On Descartes’ Passive Thought: The Myth of Cartesian Dualism. Trans. Christina M. Gschwandtner. Chicago: University of Chicago Press, 2018. 304 pp.
Review by Raoul Moati
The main project of Jean-Luc Marion’s last book is to refute the claim according to which René Descartes’s conception of the mind-body relation is based on the substantial union of two different prior substances: the mind, on the one hand, and the body, on the other.
Marion’s central hypothesis is that the history of the reception of Descartes’s philosophy is based on the occultation of what Marion calls “Descartes’ profound speculative intention” (p. 21), which primarily consists in the elaboration of a nondualistic picture of mind-body union. For Marion, such a “profound speculative intention” has eluded the grasp of the succession of readers and interpreters of Descartes. However, this misinterpretation is the responsibility not only of Descartes’s interlocutors but of Descartes himself. According to Marion, Descartes himself “compromises his own theoretical advance” (p. 4). There is in fact an argumentative tension internal to the Meditationes that obscures Descartes’s actual position regarding the mind-body problem. On the one hand, Descartes would have to over-exaggerate his hyperbolic doubt by artificially including his own body in it, in order to reinforce the certitude of the ego sum. On the other hand, Descartes would have to defend the idea of the fundamental certainty of his own body, which resists hyperbolic doubt, to accord with the ego sum. According to Marion, the exaggerated inclusion of his own body (meum corpus) in his hyperbolic doubt results in the misunderstanding of Descartes’s actual position regarding the very status of the subjective body. In order, then, “to allow the real question to surface,” Marion argues, one has to start by restraining these common interpretative impulses. Of these, and above all, one must resist the temptation of “raising the problem of the supposed ‘Cartesian dualism’” (p. 5). From there, Descartes’s fundamental theoretical intention can be made clear.
As Marion says: “it is possible that nothing stigmatizes the semantic inadequacy of substantia more than the innovation of the meum corpus and of the union” (p. 161). What does this mean? Nothing less than the attempt to prove that my body, meum corpus, is nothing like a second substance that joins my soul in forming a third substance that would coincide with the union as such. Marion speaks of Descartes’s “silent refusal” “to erect the union itself as a third substantia” (p. 161) and shows how the controversies with Regius lead Descartes to use a vocabulary of the substance that cannot correspond to what he means by meum corpus. As Marion says: “any solution to the aporia in which Regius is stuck cannot come from a simple correction or formulations drawn from substantia and from its compositions; one must retrace one’s step (or jump ahead without turning around) by breaking with the language of substance” (p. 172). This is why Descartes will have to “jump ahead” to the vocabulary of substantia in order to avoid all the conceptual distortions that vocabulary implies.
For Descartes, my body is a subjective body, a Leib, not a Körper (an objective body). What is a subjectified body? A body which is the material field of the deployment of passive thoughts understood as the last mode of the thinking substance: the sense (the sensus). For that reason, “because the meum corpus ensures to the mens one of its modes of thought, its sensus, and because this mode, althought necessitating a peripheral addition, belongs by right to the essential definition of the cogitatio, thus the thinking substance, the meum corpus, in this way added (united to the mens) belongs to it substantially, just as much as the other modes of the res cogitans” (p. 194). The body is not a substance but belongs substantially to the sole substance of the union which gives it its own substantiality: the mens. For that reason, my body must not be understood as an additional substance forming a third one with the soul but as the very material extension of a mode of my own thinking as deployed passively under the mode of the sensus.
Marion concludes that Descartes anticipated Heidegger’s discovery of (1) the human being as a being-in-the-world understood as a nonsubstantial being and of (2) the nonsubstantiality of the surrounding world that itself takes the form of commodo and incommoda—which means, in Heideggerian terms, in the mode of being of the Zuhandenheit.
I don’t think on this particular point that I can follow Marion’s reading of Descartes through to its end. If I am not in my body like “a sailor is present in his ship” (to use Descartes’s famous expression) it is precisely because I am concerned in everything that happens to my body (its affections). Every time my body is touched by another body, this impact implies the formation in my soul of a sentiment, or in other words, a vivid but confused idea that—as in the case of the heat—informs me about a potential danger for my survival as a whole human living on earth. In that sense, I would not be inclined to fully agree with Marion’s very seductive comparison with Heidegger’s Zuhandenheit. The understanding of an entity as a Zuhandenes opens access to the being of an entity as understood by the Dasein, while for Descartes the adventitious ideas are nothing like the unveiling of the being of the thing perceived. Confused ideas, for Descartes, never refers to the thing itself but rather to the sort of danger it may represent for one’s own safety in the world. Heat and pain, for example, are not properties of my surrounding universe for Descartes, but properties of my own relation to the objects that surround me. In that sense, adventitious ideas are nothing other than what Descartes calls the “teachings of nature,” in other words, a way by which nature teaches me which object I should pursue and from which I should flee. I would be more in favor of distinguishing between subjective confused ideas—which are nothing else than what nature teaches me about the potential danger for my safety from things which surround me—and objective clear and distinct ideas—which consider the external things in terms of extension, number, figure, measure, and so on. If one wants to use Heidegger’s terminology here, I would say that in Descartes I do understand the being of an entity when I understand that entity as a Vorhanden, namely as a substance having geometrical properties. The being of an external entity is always given to the Cartesian cogito under the form of a Vorhandenes: a substantial thing.
 René Descartes, “Meditations on First Philosophy”: With Selections from the Objections and Replies, trans. and ed. John Cottingham (New York, 1996), p. 56.