DESCARTES’ NOTION OF MEUM CORPUS AND JEAN-LUC MARION’S CHALLENGE TO “THE MYTH OF CARTESIAN DUALISM”

Jean-Luc Marion, in his latest book, “Sur la pensée passive de Descartes,” recently published in an English translation, challenges something he refers to, in the English subtitle, as “the Myth of Cartesian Dualism” and counters it with his original interpretation of Descartes’ notion of meum corpus. This article explores the reasons he adduces for this purpose. The case is made that Marion fails to provide sufficiently solid argumentative and textual support for his construal in this respect and that traditional substance dualistic interpretative resources allow for a more straightforward and systematic reading. It is argued that Marion’s central dualism-deflecting claim, that in the Meditations, “my body” is not an extended thing but a mode of thought, is undermined by an analysis that carefully considers the context of those Descartes’ statements to which Marion appeals.

However, Marion's book draws much attention also for another reason. It seems to challenge, as the subtitle of the English translation reveals, something referred to as "the myth of Cartesian dualism." This makes the book not only interesting from the perspective of phenomenological tradition but also very intriguing from the perspective of analytic tradition because debates about such things as dualism, materialism, etc., are still rampant in it. (They are central to one of the main branches of contemporary analytic philosophy, namely, philosophy of mind.) Notably, the subtitle is absent in the French original [Marion 2013] and the word "myth" is not used anywhere in the body of the text; however, it is hardly plausible that the subtitle did appear in the English translation without the author's approval. Again, the appearance of this subtitle in the translation seems to be specially targeted at Englishspeaking readers and may be connected with the prevalence of the analytic philosophical tradition in English-speaking countries, especially Great Britain.
This article attempts to evaluate Marion's theses and arguments concerned with ("the myth of") Cartesian dualism from the analytic perspective, while also supplying the relevant background for "the trialist debate." Regrettably, I think that Marion's case against "the Myth of Cartesian Dualism" leaves much to be desired in the respects of clarity and cogency of arguments. To begin with, there is no explicit explanation as to what the target of Marion's critique is. Is Marion trying to undermine the traditional view that Descartes was a dualist, in a rather well-known sense, and to show that it was not really the case, just a later-devised myth? Or is his point in that there are some (supposedly influential and worth bothering about) views about Cartesian dualism that are mistaken, being just a myth? If so, what are these views? The reader is left to guess.
Whatever the case, it seems that Marion thinks that something is wrong with the dominant way of understanding Descartes' philosophy of mind and body along the dualistic lines and proposes his remedy to this. What is wrong about it has to do with the combination of dualism and Descartes' statements about the substantial union of mind and body. This combination is, in many Cartesian scholars' view, highly problematic, so Marion tries to tackle this problem. The gist of his proposal is the thesis that Descartes' term meum corpus (my body) designates not a body as res extensa, an extended material thing, but a passive mode of thought, that is, something that belongs to one's mind. Marion considers it a precursor of the contemporary phenomenological notion of flesh. I guess that what is meant can be explained by distinguishing my body as a physical object (characterized, as res extensa, by its spatial location, size, form, and potentially infinite divisibility into cells, molecules, atoms, subatomic particles, and so on) and my experiences of this body. Let us designate the whole complex of these experiences as a person's phenomenological body. (A useful illustration is that of a phantom limb: a person who has lost a leg often feels pain in that leg as if it were still there. So, although the leg is absent physically, it can be said to be present phenomenally.) In these terms, Marion's thesis seems to be that Descartes' term meum corpus refers not to my physical body but to my phenomenological body. If this is so, then there are two questions to consider: 1) Does this interpretation make a better systematic sense of the whole corpus of Descartes' works (and especially, the work that is usually considered as his most important one, Meditations) than other available interpretations (probably, along dualistic lines)?
2) If Descartes' term meum corpus refers to my phenomenological rather than my physical body, then how does it change our perception of the Cartesian dualism-or-whatever-it-is? I think that the answer to the second question is: not much, except for the problems having to do with the first question. If Descartes used the term meum corpus to refer to my phenomenological body, then, anyway, he argued for the substance-dualistic doctrine that basically, there are two kinds of things-substances in the God-created world: minds (or souls, or res cogitans) and physical bodies (res extensa), and one of these bodies is my physical body, which is characterized by its spatial location, size, form, and potentially infinite divisibility. That my mind has active and passive parts or aspects (intellect and my phenomenological body, meum corpus) does nothing to undermine Cartesian substance dualism. (Perhaps, it does something to undermine a myth thereof.) As for the first question, in the rest of this article, I argue for the negative answer: there is a more straightforward and systematic way to read Descartes' texts, along traditional dualistic lines, that is far less problematic than the one Marion proposes. The construal I argue for is hardly new in any particular detail. It is based on a pretty common conception of substance dualism as understood by the most prominent representatives of or sympathizers with this doctrine, especially its theistic part, in the contemporary philosophy of mind, such as Richard Swinburne, William Hasker, James P. Moreland, John Foster, and Howard Robinson. Descartes is traditionally considered to be the founder of this doctrine in its modern forms. The content of his doctrine of substance dualism, in a nutshell, is that on the most fundamental ontological level, the world consists of two kinds of things (substances), minds (souls) and bodies; that minds and bodies are really distinct (capable, in principle, of existing without one another); that they have entirely different natures determined by two different attributes, of thought and extension; however, in the actual world, human souls are united to and closely interact with particular bodies (brains included), so that there is the substantial union of a human soul and a human body.
There is vast textual evidence that Descartes held this doctrine. Although he did not use the word "dualism," the doctrine that (a) minds and bodies are distinct things, that (b) all there is in the world, on the most fundamental ontological level, are minds and bodies (or minds and physical reality), and that (c) a human being is a two-part "composite" of a non-physical mind and a physical body, is just what the classificatory term "substance dualism" means.

Preliminary notes on the possibly relevant debate about Descartes' trialism
Marion is not the first interpreter of Descartes who seems to question his dualism. Recently, a number of historians of philosophy -most influentially, John Cottingham and Paul Hoffman -argued that Descartes was a trialist. Trialist interpretations of Descartes raised lively discussions in the 1980s-90s, in which supporters of the more traditional, dualistic construal, seem to have successfully held their ground. As a result, the interest in Descartes' supposed trialism gradually subsided. Some of Marion's remarks make it plausible that his jabs at Cartesian dualism may be understood with reference to that discussion about trialism, so it seems appropriate to discuss shortly the most relevant points the trialists usually make.
The most crucial thing is that the claim that Descartes was a substance dualist (in the generally accepted sense I outlined in the previous section) is perfectly consistent with the possibility that Descartes was a trialist or some other n-ist in some respects. In fact, Cottingham, Hoffman, and, as far as I know, other trialist interpreters do not deny that Descartes held those views that go under the name of "substance dualism." The trialism they attribute to Descartes is not about the ontology of fundamental substances.
First, they appeal to Descartes' explicit statement that there are three "primitive notions," those of soul, body, and their union. So far so good. I think it should be admitted that Descartes was a trialist as regards these primitive notions; this does not conflict at all with Descartes being a substance dualist. 2 Second, more controversially, they argue that each of these primitive notions is associated with its own modes. This conflicts with the usual view that Descartes' dualism involves a "sharp dichotomy of properties into two kinds," that is, the claim "that all modes are either purely mental or purely physical" [Hoffman 1990: 310-311]. In particular, trialist interpreters argue that Descartes considers sensation to be a mode of the mind-body union rather than a mode that is appropriate for the mind alone [Cottingham 1985] or "the mind's side" of a mode that "straddles mind and body" [Hoffman 1990: 318, 330-331]. They also suggest that the same obtains for other "passions of the soul," such as appetites and emotions, "as well as the ideas of the imagination, and volitions terminating in the body" [ibid.: 330-331]. There is much to say -and there was much that opponents already said -against this construal, but this topic goes far beyond the scope of my article. Anyway, even if Cottingham and Hoffman are right in this respect, this would establish only that Descartes was a trialist as regards properties (modes) 3 but leave unaffected the claim that he was a substance dualist.
Third, trialist interpreters are sometimes understood to claim that the mind-body union or "human composites" are a third kind of substance, alongside minds and bodies. In particular, Marion writes about Cottingham that he "goes all the way to invoking a trialist position of substance, where the third primitive notion would hold the rank of substance, just like the first two" (p. 190). However, this is a strange misreading, for in fact, Cottingham explicitly admits that "Descartes recognizes a third category or notion alongside thought and extension without proceeding to reify it as a separate substance" [Cottingham 1985: 229]. Hoffman's view seems to be different: he argues that in Descartes' terms, a human being as a "composite" of soul and body should have counted as a special kind of substance [Hoffman 1986;1990: 318;. The main objection against this is that Descartes never described "human composites" as substances. However, I think that this objection is not sufficiently strong because, given Descartes' definitions and theories, there is no reason to deny that human composites are substances. It is clear that for Descartes, there exist composite substances that consist of other substances. Thus, Descartes describes human bodies as well as their parts (hands, legs, etc.) precisely as substances. Now, if there are composite substances that consist of parts that have the same type of nature (bodies), why a composite that consists of two parts having different natures (soul and body, standing in the special relationship of the substantial union) should be denied the title of "substance"? Descartes' definitions and explanations about substances do not prohibit such titling. However, even if in Descartes' system, human composites can be properly called "substances," these substances are not ontologically fundamental, exactly because they are composite substances that consist of two onenatured substances, soul and body. So, Descartes' substance dualism is not undermined.

Marion's introductory engagement with Cartesian dualism
Marion's engagement with Cartesian dualism-or the myth thereof-begins in Introduction ( §1), as early as p. 2, where he writes: "… the distinction of two types of substances, such as predominates in almost all of the Meditations, results nonetheless in enforcing the union of soul and body on all of metaphysics from the second part of the Sixth Meditation onward. It does so with difficulty but definitively. And, in fact, this culminates in leading us to a third ʻprimitive notion,' namely that of ʻthe union' of ʻsoul and body together.' One cannot fail to be surprised that the supposedly unprecedented discovery of the distinction could (and must) lead to what at least apparently contradicts it, namely the union of soul and body. What kind of logic -possibly quite concealed -would allow us to continue to safeguard the coherence of the Cartesian advance? Or is this a matter of definitive incoherence?" Let us note two points concerning this fragment. First, it admits that "the distinction of two types of substances … predominates in almost all of the Meditations." If so, and if Descartes later did not renounce this most prominent point of the Meditations, how Cartesian dualism can be a myth? As far as we know, there is no textual evidence that would allow one to talk of such a renunciation while the evidence to the contrary is abundant.
Second, in the fragment, Marion takes for granted and obvious ("One cannot fail to be surprised") that "the distinction of two types of substances … at least apparently contradicts … the union of soul and body". However, this is not obvious at all.
Consider the set of claims involved: (1) There is a thing M, whose nature is T, and there is a thing B, whose nature is E.
(2) T and E are entirely different.
(3) M is capable, in principle, to exist without B, and B is capable, in principle, to exist without M.
(4) In fact, M and B are closely connected and interact with each other, so there is a union of M and B.
What apparent contradictions are supposed to be implied in these claims? I "cannot fail to be surprised," using Marion's own words, about what kind of logic could entitle one to claim that there is an apparent incoherence in (1)-(4)?
Probably, one can explain Marion's claim about incoherence by saying that there were many philosophers, from Descartes' to our contemporaries, who believed that substances that were entirely different in their natures could not possibly interact and, consequently, form a union that involved interaction. However, Descartes and many later philosophers amply explained that this belief was "a supposition that is false and cannot in any way be proved" (AT IX-I, 213:19-20 / CSM II, 275). 4 (For an illuminating discussion of this issue see [Richardson 1985].) Another possibility is that Marion fails to distinguish trialism about primitive notions from trialism about ontologically fundamental substances. The former is perfectly consistent with Cartesian dualism, in the usual sense of substance dualism, whereas the latter straightforwardly contradicts it. However, although there is good textual evidence that Descartes held the former, there is no textual evidence that Descartes held the latter. This second possibility is the more likely one, given that later, on pp. 189-190, Marion mistakenly ascribes to John Cottingham the view he in fact explicitly denies, that for Descartes, the third primitive notion, of the substantial union of soul and body, holds "the rank of substance, just like the first two" (p. 190). See the discussion about it in the preceding section.
A few pages later (p. 5), Marion suggests that to understand properly Descartes' treatment of the passivity of thought (especially, in The Passions of the Soul) "one must begin by not raising the problem of the supposed 'Cartesian dualism'; even if, as one criticizes it, it does not cease to be reborn in a derived form or in its ancient absurdity." Here, again, something is taken for granted and obvious, without explanation and arguments. In particular, we are left to guess as to what "the problem of the supposed 'Cartesian dualism'" and "its ancient absurdity" are supposed to be. Marion continues, in the next sentence: "Actually, this 'dualism' tries to resolve a question that Descartes takes to be already resolved in fact: experience proves to us that soul and body, at least my soul and body, are so closely united that certain thoughts modify certain movements, and do so reciprocally." I find the purport of this statement obscure. Cartesian substance dualism-the doctrine that soul and body are two distinct ontologically fundamental entities with entirely different natures-was not advanced in order to solve the problem of soul-body interaction. Descartes's rationale for this doctrine was diligently explained in the Meditations. Many philosophers used to believe that dualism gave rise to the problem of soul-body interaction and that this problem was very grave. Descartes denied this and indeed took the question of soulbody interaction "to be already resolved in fact." ([Richardson 1985] explains very well how Descartes could be right about this.) What does it have to do with Marion's allusion to the "ancient absurdity" of dualism? And what is this absurdity supposed to be?
There is another interesting point about Marion's statement that Descartes held the view that "experience proves to us that soul and body, at least my soul and body, are so closely united that certain thoughts modify certain movements, and do so reciprocally". The point has to do with the word "modify," which is Marion's replacement for Descartes' causal words "impel," "move," "act on," and "cause." Marion's statement has its origin in Descartes' letter to Arnauld (29 July 1648), where he writes that "  [Descartes 1985], abbreviated as "CSM"; Volume III of The Philosophical Writings of Descartes, transl. by J. Cottingham, R. Stoothoff, D. Murdoch, and A. Kenny [Descartes 1991], abbreviated as "CSMK"; The Philosophical Works of Descartes, transl. by E. Haldane and G. R. T. Ross [Descartes 1931], abbreviated as "HR"; Philosophical Letters, transl. by A. Kenny [Descartes 1970], abbreviated as "K". The abbreviation is followed by a blank space, the volume (if any, in Roman numerals), a comma, and the page number. For AT, the abbreviation is followed by a colon and the numbers of rows. its sensations and passions" (AT III, 665:22-24 / CSMK, 218). He also points out that "people who never philosophize and use only their senses have no doubt that the soul moves {French: meuve} the body and that the body acts on {French: agisse sur} the soul" (AT III, 692:4-6 / CSMK, 227). However, there is a telling difference between Marion's and Descartes' formulations: Descartes does not use the verb "modify." Instead, in his formulations, we encounter "impel" (Latin: impellō), "move" (French: mouvoir), "act on" (French: agir sur), and "cause" (French: cause). The purpose of this replacement is not clear but it tends to downgrade the difference between body and soul (mind) from that of distinct substances to that of different modes of the same attribute (thought), in line with Marion's later claim that Descartes' "my body" means not a body qua res extensa but something that "exists as thought" (p. 43).

On what Marion takes to be the aporia of the Sixth Meditation and the failure of Descartes' argument for the existence of material things
In the next section (Chapter 1, §2), Marion claims that the Sixth Meditation contains an aporia; it "is defined as an apparently (and maybe really) incoherent project, for even the title announces an obvious duality: 'De rerum materialium existentia et reali mentis a corpore distinctione -The existence of material things and the real distinction between mind and body'" (pp. 12-13) That is a puzzling claim. Apparently, on the traditional interpretation of Descartes (which Marion so far did not refute), there is no incoherence in the project, and the "duality" involved in the title was, for Descartes, a matter of establishing two allied rather than contradictory claims. The existence of material things (bodies), as well as minds (souls), and the real distinction between them is exactly what substance dualism is about.
However, Marion insists that "there is an exclusive duality at stake", and that it is an "inexplicable juxtaposition" (p. 13). For this, no argument has been presented so far. Moreover, the "inexplicable juxtaposition" has an obvious explanation: given that in the preceding Meditations (I-V) Descartes (claimed to have) established beyond doubt the existence of his self (mind) as a thinking thing (substance) and the existence of God, what remains for him to do in the Sixth Meditation, in order to obtain his full dualistic ontology, is exactly to establish that (1) material things (bodies, one of which is my body) exist and (2) they are all really distinct from minds (in particular and especially, that my body and my mind are distinct substances). 5 No incoherence is involved in the project.
Marion questions: "Does the body in question, this body that is so specific that what is at stake is in fact and by right nothing less than my body, belong to the realm of 'material things' like a little territory in a much larger province, or does it constitute a domain that is irreducibly other and obeys different principles?" (p. 13) However, no argument has been proposed so far against the former and in favor of the latter supposition. Marion's reader is left to wait for such an argument at least until Chapter 2. 5 When writing of "the real distinction between mind and body," Descartes meant not just the general distinction between minds and bodies but especially the distinction between the mind and the body of a human being -or, in the first-personal presentation of the Meditations, the distinction between my mind and my body. This distinction is of special importance because we are naturally disposed to identify ourselves with our bodies and, therefore, tend to have confused ideas of ourselves in which the proper distinction is not drawn. My body is also epistemically accessible to me in ways no other bodies are and this is what makes it my body: "There is nothing that my own nature teaches me more vividly than that I have a body, and that when I feel pain there is something wrong with the body, and that when I am hungry or thirsty the body needs food and drink, and so on" (AT VII, 80:27-30 / CSM II, 56).
In the meantime, Marion argues that Descartes' proof of the existence of material things is deficient. For the largest part, he rehearses the criticisms and strictures of this proof that Leibniz, Malebranche, Hume, Kant, and others advanced before him. Besides, Marion questions "whether the proof for the existence of material things really has true value as proof in Descartes' eyes, in the sense in which the Second and Third Meditations (reinforced by the Fifth) had demonstrably established the ego's and God's existence" (p. 15). The reason to doubt this is Descartes' own statements in the Synopsis to the Meditations: he writes that in the Sixth Meditation he made "a presentation of all the arguments which enable the existence of material things to be inferred", that "[t]he great benefit of these arguments is not … that they prove … that there really is a world, and that human beings have bodies and so onsince no sane person has ever seriously doubted these things" but "that in considering these arguments we come to realize that they are not as solid or as transparent as the arguments which lead us to knowledge of our own minds and of God, so that the latter are the most certain and evident of all possible objects of knowledge for the human intellect" (AT VII, 15:26-16:7 / CSM II, 11). However, here Descartes' point seems to be not to depreciate his final argument for the existence of material things-he would hardly make this argument if he did not think that it is sound -but rather to extol his arguments about our own minds and God as "the most certain and evident of all possible objects of knowledge for the human intellect". As for the existence of material things, first, no sane person (supposedly, Descartes included) has ever seriously doubted it and, second, it is supported by the argument of the Sixth Meditation, even if Descartes was not so sure of this argument as of his arguments about our own minds and God.

Is my body a body?
In Chapter 2, Marion advances and argues for the construal, according to which for Descartes, my body does "constitute a domain that is irreducibly other and obeys different principles" rather than "belong to the realm of 'material things'" (p. 13).
To begin with, Marion objects against the traditional understanding according to which in the Meditations, (answering) the question of the existence of material things precedes (and conditions answering) the question about the real distinction between mind and body. However, the reasons Marion provides for this objection are flawed.
First, in the Fourth Set of Replies (to the objections made against the Meditations) Descartes says: "[E]verything I wrote on the subject of God and truth in the Third, Fourth and Fifth Meditations contributes to the conclusion that there is a real distinction between the mind and the body, which I finally established in the Sixth Meditation" (AT VII, 226:23-26 / CSM II, 159). Marion suggests that in this, "Descartes turns this distinction into the result and the sole conclusion of the preceding meditations, flatly passing over the question of the existence of material things in silence … as if the existence of material things could simply be either skipped over, so to say, or passed over in silence as a consequence" (p. 41).
I think that such a take of Descartes' quoted statement suffers from the amazing neglect of context: in the Fourth Replies Descartes was not rehearsing the whole chain of the argument in Meditations; he mentioned only what was relevant for his immediate purpose, as part of his reply to a particular objection. The objection was "that although I can obtain some knowledge of myself without knowledge of the body, it does not follow that this knowledge is complete and adequate, so as to enable me to be certain that I am not mistaken in excluding body from my essence" (AT VII, 223:25-28 / CSM II, 157). Descartes' purpose was to "explain how the mere fact that I can clearly and distinctly understand one substance apart from another is enough to make me certain that one excludes the other" (AT VII, 225:26-226:2 / CSM II, 159). The objection at issue did not question (Descartes' proof of) the existence of material things and, in particular, of those material things which are human bodies, but took it for granted. This perfectly explains why Descartes had no need to mention his proof of that existence in his reply.
Really, Descartes' statement in the Fourth Set of Replies has hardly anything to do with turning the distinction between the mind and the body "into the result and the sole conclusion of the preceding meditations". Firstly, it does not turn it into the sole conclusion (and the result), for other results and conclusions are not mentioned merely because they were not asked about. Secondly, as far as this one conclusion goes, Descartes' statement tells explicitly that the preceding meditations do not establish that conclusion definitively -they only contribute to it.
Second, Marion claims that "the first paragraph of the Sixth Meditation, which sets forth the problem as a whole, very explicitly announces that the existence of at least one body precedes the demonstration of the existence of (other) corporeal things: one existence, that of material things …, certainly turns out to be rather problematic, but a different existence is in the end discovered to be already assumed beyond discussion, that of my own body" (p. 41). However, this claim is not really supported by Descartes' texts to which Marion appeals.
The first one, from the first paragraph of the Sixth Meditation, is that "when I give more attentive consideration to what imagination is, it seems to be nothing else but an application of the cognitive faculty to a body which is intimately present to it, and which therefore exists" (AT VII, 71:23-72:3 / CSM II, 50). However, pace Marion, this statement is far from announcing "that the existence of at least one body precedes the demonstration of the existence of (other) corporeal things" and from assuming beyond discussion the existence of my own body. For that matter, the crucial phrase in Descartes' statement is "seems to be" and that is (especially in the context of Meditations, in which almost everything that seems to be the case is methodically questioned) a far cry from "is, beyond discussion".
Marion points out that a "sufficiently clear argument backs up this reasoning" (p. 41). Indeed, Descartes advances such a supporting argument, whether sufficiently clear or not. However, having that admitted, we are to pay attention to how Descartes himself estimates the force of the argument. And he is perfectly explicit about this. Consider the fragment: "And I can easily understand that, if there does exist some body to which the mind is so joined that it can apply itself to contemplate it, as it were, whenever it pleases, then it may possibly be this very body that enables me to imagine corporeal things… I can, as I say, easily understand that this is how imagination comes about, if the body exists; and since there is no other equally suitable way of explaining imagination that comes to mind, I can make a probable conjecture that the body exists. But this is only a probability; and despite a careful and comprehensive investigation, I do not yet see how the distinct idea of corporeal nature which I find in my imagination can provide any basis for a necessary inference that some body exists." (AT VII,(20)(21)(22)(23)(24)(25)(26)(27)(28)51) The body about which Descartes writes in the first sentence is, supposedly, my body. At least, Marion assumes it. If it is not, then his argument collapses straightaway. The body about which Descartes writes in the second sentence is the same body, which is clear from the fact that Descartes considers it, as in the first sentence, as a hypothetical precondition of imagination. He straightforwardly says that the existence of this body is merely "a probable conjecture", "only a probability", but a merely probable premise cannot serve as the foundation for the necessary conclusion Descartes is after. So, Descartes concludes, "I do not yet see how the distinct idea of corporeal nature which I find in my imagination can provide any basis for a necessary inference that some body exists." Far from supporting Marion's construal, Descartes' formulation of this argument directly contradicts it.
It is exactly because the argument at issue, if it had the required certainty, would establish the existence of bodies, or at least of one body (that is, mine), that Descartes presents and moots it. Since the argument is found wanting in certainty, Descartes moves on to another argument for the existence of material things -the one based on the thesis that God is not a deceiver. So one can only wonder how Marion could conclude from this that " [t]here is thus at least one body whose existence is not in question: mine, more exactly the one that turns out to be required by the exercise of one of the modes of thought, the imagination" (p. 42). Descartes' statements, far from confirming, directly refute this.
There is yet another consideration against Marion's construal of this argument. Consider once again the first sentence in the quoted fragment. Together with Marion, we assume that Descartes writes here about my body. However, he does not use the phrase meum corpushe uses the phrase corpus aliquod, that is, some body. Some body is a body among bodies. If bodies generally are material things, res extensa, then some body has the same nature. Otherwise, if, as Marion claims, my body (meum corpus) is so special that it is not really a body qua a material, extended thing (res extensa), but a part of the mind (mens, res cogitans), then he would not have called it some body.
Marion also appeals to the following Descartes' statement: "There is nothing that my own nature teaches me more vividly than that I have a body, and that when I feel pain there is something wrong with the body, and that when I am hungry or thirsty the body needs food and drink, and so on. So I should not doubt that there is some truth in this." (AT VII,56) Marion interprets this in the sense that "while the existence of bodies must still be proven, that of my body or flesh is already and straightforwardly imposed as a certainty" (p. 45). However, this construal again neglects the context. The statement at issue follows shortly after Descartes presents his main proof of the existence of material things, which is as follows: "But since God is not a deceiver, it is quite clear that he does not transmit the ideas to me either directly from himself, or indirectly, via some creature which contains the objective reality of the ideas not formally but only eminently. For God has given me no faculty at all for recognizing any such source for these ideas; on the contrary, he has given me a great propensity to believe that they are produced by corporeal things. So I do not see how God could be understood to be anything but a deceiver if the ideas were transmitted from a source other than corporeal things. It follows that corporeal things exist." (AT VII, 80:16-25 / CSM II, 55) Descartes' proof of the existence of his own body, and of a real distinction between his mind and his body is a direct continuation of the preceding argument for the existence of material (or corporeal) things generally. In both, Descartes finds the certainty of the existence of corporeal things and his own body in that God is not a deceiver: "… the very fact that God is not a deceiver, and the consequent impossibility of there being any falsity in my opinions which cannot be corrected by some other faculty supplied by God, offers me a sure hope that I can attain the truth even in these matters. Indeed, there is no doubt that everything that I am taught by nature contains some truth. For if nature is considered in its general aspect, then I understand by the term nothing other than God himself, or the ordered system of created things established by God. And by my own nature in particular I understand nothing other than the totality of things bestowed on me by God." (AT VII, 79:22-80:4 / CSM II, 55-56) Admittedly, with respect to his own body, Descartes appeals to another mode of givenness than in the case of other bodies. Here, he mentions not just the perceptual givenness of external extended bodies but also such sensations as pain, hunger, thirst, etc. However, this does not in any way preclude Descartes from considering his body as a purely material, extended thing. Again, Descartes is perfectly unequivocal about this: "… on the one hand I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far as this is simply an extended, non-thinking thing. And accordingly, it is certain that I am really distinct from my body, and can exist without it." (AT VII, 78:15-20 / CSM II, 54) (Italics mine.) Yet another purported textual evidence to which Marion repeatedly appeals (pp. 44,45,68,99,173) is Descartes' phrase "meum corpus sive potius me totu[s] -my body, or rather my whole self." Marion interprets it as the statement of identity that my body is my whole self, that "my body … not only belongs to me but is myself" (p. 46), "this body of mine that is me myself" (p. 48); from this, he concludes that my body cannot be a material thing but should rather be a mode of thought, "my thinking flesh" (p. 39). 6 However, this is again an unjustified interpretation. Let us pay attention to the context. Descartes' statement is as follows: "my body, or rather my whole self, in so far as I am a combination of body and mind, can be affected by the various beneficial or harmful bodies that surround it" (AT VII, 81:24-27; AT IX-1, 65 / CSM II, 56).
The meaning of the statement is not the identification of my body with my whole self; it just says that what is "affected by the various beneficial or harmful bodies that surround it" is not just my body but rather "my whole self, in so far as I am a combination of body and mind." The statement is unequivocally dualistic: mind and body are taken to be two things of which I am a combination; there is no identification of my body with my whole self; rather, "my whole self" is here used to signify "a combination of body and mind," of which my body is one part and my mind is another.
One can note that this may not fit well with the rather widespread perception that Cartesian dualism strongly contrasts the thinking self, the res cogitans, and the physical body, the res extensa. It may seem that such a dualism commits one to the identification of one's self with the mind, the res cogitans; this, in turn, requires that my body should be either outside of my self or inside of my mind (as its mode). Perhaps it is this consideration that guides Marion's interpretation. However, the dilemma outlined is a spurious one because the belief that Cartesian dualism opposes the mind to the body so radically that they cannot make "a combination" which could be identified with my (whole) self is really a myth or rather a caricature on the Cartesian dualism. Surely, Descartes holds that my mind and my body are in a substantial union, forming a unity of a rather strong kind but this is the unity (union) of two distinct things with entirely different natures, one of which is a thinking thing, mind, and the other is a material (extended) thing, body. Given this special intimate relationship of my body with myself considered as res cogitans, nothing prevents Descartes from using the phrase "my whole self" to designate the composite rather than its mental component alone. Admittedly, this involves some ambiguity in the use of the phrase "my self" or the pronoun "I" which is sometimes (when the distinctness is at issue, especially often in the Meditations) used to mean only a mental subject (my mind, or soul, the res cogitans) and sometimes (especially, when the unity is at issue) to mean the composite of a mental subject and his or her body. But that ambiguity is perfectly innocuous and natural for a dualist: qua a dualist, I hold that I am primarily a mental subject, this is my "core self." Nevertheless, given the intimacy of my relationship with my body, I can hardly avoid identifying my body with myself in a lot of contexts (at least, such avoidance would be very inconvenient for me) and, as a consequence, having an extended notion of myself, "my whole self," which includes both my "core self" (myself as a mental subject) and my body. Instead, Marion's interpretation involves imputing Descartes with a really malign equivocation that incorrectly conflates the word "body" and the phrase "my body." Marion admits that, according to his interpretation, in Descartes' system, "the term body benefits (or suffers) from a fundamental ambiguity", even "radical ambiguity" (p. 43). He finds it surprising "that imaginative thought involves something that Descartes still calls a body" (p. 42). Still, he insists that "[a]lthough this other thing is called a body, it hence exists as thought" (p. 43). Moreover, Marion's construal suggests ambiguity not only in the case of the term "body," insofar as "my body" is not a material thing but a mode of thought, whereas other bodies are mind-independent material things, but in the case of the phrase "my body" as well. Marion admits that at least in two occurrences in the Meditations (AT VII, 85:29, 86:4) "my body seems rather explained as an extended body" (p. 44). 7 Let us think of how queer Descartes' philosophy should be if this construal were true. From one work to another, throughout his mature philosophy, Descartes explicitly states his views and argues that there are fundamentally two kinds of things (substances), material extended bodies and immaterial minds (souls), and that my mind is really distinct from my body. Now, we are invited to believe that despite this, he in fact holds that my body is-or uses the phrase "my body" to signify-not a material extended thing but something intrinsic to mind, and never informs his reader about this. When his numerous critics challenged his claim that immaterial minds interacted with material extended bodies, and when his more sympathetic readers asked him how such interaction was possible, Descartes never said that he did not mean such interaction and that my body was not a material extended thing at all. Notoriously, Descartes localized the place of mind-body interaction in the pineal gland. Should we believe that by "pineal gland" he meant a thinking immaterial flesh rather than an extended body? Did not Descartes believe that his body, as well as any other body, was located in space in a certain way (relative to other bodies), had a shape, size, etc., and was divisible into parts, which were themselves extended bodies? Or should we think that Descartes believed that he had two bodies, one material and extended, and the other intramental (phenomenal)? If so, how do these bodies relate to each other? Do they causally interact? How about Descartes' second argument for the real distinction, which is that "the body is by its very nature always divisible, while the mind is utterly indivisible" (AT VII, 85:29-86:1 / CSM II, 59), where he talks primarily about the human body, the one to which the mind is united, the one that has feet and arms (AT VII, 86:4-7 / CSM II, 59), as well as any other body, when he writes that "there is no corporeal or extended thing that I can think of which in my thought I cannot easily divide into parts" (AT VII, 86:10-12 / CSM II, 59))? Such questions can be multiplied, and the general result seems to be that Descartes' metaphysical system is reduced to a mess.
On pp. 48-52 Marion discusses the famous fragment in which Descartes denies that I am "merely present in my body as a sailor is present in a ship" and states that "I am very closely joined and, as it were, intermingled with it, so that I and the body form a unit" (AT VII, 81:1-5 / CSM II, 56). He draws attention to the fact that in his earlier book, the Discourse on Method, Descartes made a similar claim but wrote not "a sailor" but "a pilot" (AT VI, 59:8-16 / CSM I 141), and that with the Meditations, "de Luynes' translation judiciously (so it seems) chooses to render it twice by 'pilot' instead of the 'sailor' one would expect" (p. 51). Marion points out that there can be a considerable difference between a sailor's and a pilot's relationship to the ship, and that this difference was emphasized by Plotinus. The pilot's relationship to the ship can be much closer than that of a mere sailor, for "the pilot, the skipper, knows the boat, possibly owns it, guides it, feels it vibrating and working, even senses it living, as one says, as if it were extension of his own body into the limbs and the masts of the vessel;" he "belongs to the ship and is -almost -one with it" (p. 51). Given this and Descartes' statement that the mind "is more closely united to the body than even the pilot (and not just the simple sailor) to his ship," Marion concludes that "the Cartesian conception of the union … asks … a union going all the way to a perfectly homogenous mixture" (pp. 51-52). Marion even describes this as an "unambiguous decision." However, this conclusion is non-sequitur. Even if Descartes held that the soul was united to the body more intimately than the pilot to his ship-which is likely to be the case-this falls short of "a perfectly homogenous mixture." In fact, Descartes himself, in the fragment discussed, used the phrase "as it were, intermingled" (Latin: quasi permistio), the phrasing very far from "unambiguous." It is easy to see that in some important respects, we are indeed more closely united to our bodies than even a pilot is to his ship. The feel of my body and my control of the movements of its limbs is obviously much more direct, which encourages the phenomenology of "as it were, intermingling." But this description is perfectly consistent (Descartes clearly held that it is so) with my mind and my body being really distinct, and with my body being an extended thing.

It should not be a discovery that for a dualist, sensations belong to the soul
At the beginning of Chapter 3, Marion discusses Descartes' incomplete and unpublished dialogue Search for Truth, in which three protagonists make an argument very similar to that in the First Meditation -doubting the existence of all bodies, including one's own body, and affirming the indubitability of one's own existence as a thinking thing, from which the following conclusion is made: "… what I am, in so far as I am doubting, is certainly not [quite] what I call my body. Indeed, I do not even know whether I have a body… I might add that I also cannot deny absolutely that I have a body…" (AT Х, 518) 8 It seems clear that in this context, "I cannot deny absolutely that I have a body" means that although "I do not even know whether I have a body," perhaps I do have it after all.
Marion manages to interpret it in an entirely different sense: "I cannot deny it because far from only having it, I am it" (p. 83).
Then Marion highlights, as if it were a backing for his construal, that Descartes repeatedly stated that sensations belong to the soul or mind and that they are as indubitable as any other modes of thought. Marion takes this to support his thesis that for Descartes, "my body" is "flesh" (the concept Descartes did not use), which is a passive mode of thought. In fact, this is partially mistaken and partially trivial, and it perfectly fits Cartesian (substance interactionist) dualism correctly understood.
It should not be a discovery that in Descartes' view, as well as in the view of any other competent mind-body dualist, the distinction between the physical (the body) and the nonphysical mind (soul) should be drawn so that sensations qua subjective mental states (experiences) should be identified with states of mind. For a competent dualist, no body (my body included) experiences sensations, although a human body can have "sensations" in a different sense, as certain bodily movements that evoke sensational experiences in the mind. And that was clearly the view Descartes held. See, for example, his explanation in the Meditations, Replies to the Sixth Set of Objections, about "three grades of sensory response," the first of which-certain movements-belongs to the body, whereas the other two-sensational experiences and our corresponding judgments about external things-belong to the soul (AT VII, 436:27-437:11 / CSM II, 294-295). The fragment in the Second Meditation is very telling too: "… I who am doubting and understanding and willing … is also the same ʻI' who has sensory perceptions, or is aware of bodily things as it were through the senses. For example, I am now seeing light, hearing a noise, feeling heat. But I am asleep, so all this is false. Yet I certainly seem to see, to hear, and to be warmed. This cannot be false; what is called ʻhaving a sensory perception' is strictly just this, and in this restricted sense of the term it is simply thinking." (AT VII,29:5,(11)(12)(13)(14)(15)(16)(17)(18)19) The point is clearly that, whether or not we have genuine vision and hearing, in the sense that presupposes that those things we seem to see and hear do really exist, we certainly have those (visual and auditory) sensational experiences. If I seem to see a tree, I cannot doubt that I have this experience, although I can doubt that the tree I seem to see does really exist. Similarly, I can doubt whether my visual experience qualifies as genuine seeing or as delusory quasi-seeing, as in the case of Descartes' deceitful demon scenario. Besides, I can doubt that when I have this experience, I do have those movements in my body that Descartes describes as the first grade of sensory response. All this just supports the view Descartes and other dualists share that sensations are states of the conscious mind (soul) and not of the body.
Of course, one can construct the notion of "flesh" out of such "bodily" experiences, so that flesh belongs to the mind and is a passive mode of thought. But this by no means makes my body qua body, a res extensa among other res extensae, non-existent. And this leaves the relationship between me qua mind (res cogitans) and my body qua body (res extensa) just where it was. They are still two distinct things (substances) with entirely different natures that exist together in a very close (substantial) union -a special ontologically primitive causal relationship that makes a particular mind sensitive to what happens to a particular body and makes this body responsive to the volitions of this mind. That is exactly what Cartesian dualism is about.

Welcome back to dualism
Eventually, Marion seems to fail to keep to his claim that Descartes' my body "exists as a thought," for in Chapter 5 he admits that "this meum corpus really does remain a portion of extension, but one that becomes indivisible (united) because its function of passivity joins it intrinsically (unifies it) to the res cogitans, whose final mode of sensing becomes operative only with its help" (p. 189). 9 All this comes to two simple points: 1) that a body, a piece of matter, is my body (has the identity of my body) insofar as it is connected with my soul by the substantial union which involves having all the properties and functionality necessary to support this relationship and 2) that this body through the substantial union makes me-my mind, or soul-to have sensations as a passive mode of thought, which I would not have without it. Yet the double point that Marion emphasizes in this chapter is that the union is ontologically primitive, that is, not explainable in terms of anything more fundamental, and that it is neither a substance nor an accident (pp. 190-191). All this is, of course, true; however, it is no news and does not contradict Cartesian dualism. As Marion himself points out, "this substantial union in no way contradicts the real distinction of the mens and the body, as Descartes does not stop repeating … in fact, the mens remains a complete substance even without the body." Again, there is no gainsaying to the further Marion's point that "this mens, which would no longer be united or not yet substantially united to the sensus, could think only partially, namely actively, maybe like an angel, but surely not like a human being" (p. 195). But there is no contradiction to Cartesian dualism either.