Bill Vallicella and I have been debating Aquinas’s hylemorphic dualism (HD). Earlier posts (here, here, here, and here) have focused on Aquinas’s motivations for combining hylemorphism and dualism. As we continue Bill and Ed’s Excellent Adventure, the discussion turns to questions about the internal coherence of the view. In a new post, Bill summarizes what he takes to be one of the main problems with HD. Give it a read, then come back.
Bill says that he thinks HD faces a problem similar to the one facing what he calls “compound substance dualism” (CSD), which is essentially Cartesian substance dualism together with the thesis that a person’s body is a proper part of him. The problem with this view, Bill says, is that when we ask what exactly it is that is doing the thinking when a human being thinks, CSD seems to give us two answers -- that the soul thinks, and that the composite of soul and body thinks -- and that is one answer too many. HD holds that it is the person as a whole, the composite of body and soul, which does the thinking. So far so good. But according to Bill, HD also seems to imply a second answer to the effect that the soul alone thinks, just as CSD does. For HD takes the soul to be a subsistent form, capable of persisting beyond the death of the body, because it takes our intellectual powers to be immaterial and thus independent of the body. And if they are independent of the body, then it is the intellect (or the soul in carrying out intellectual activities) that does the thinking, rather than the soul and body together. And this wavering between two answers is as unacceptable in the case of HD as it is in the case of CSD. (Bill seems to favor what he calls “simple or pure substance dualism” over either CSD or HD.)
Now Bill’s comparison between CSD and HD is in my view mistaken, for I think he fails to take seriously enough the HD conception of the soul as a kind of form. For CSD, the soul is a complete substance in its own right, and specifically a substance that thinks (res cogitans). That is why CSD seems to lead both to the conclusion that the soul alone thinks (since the soul just is a thinking substance) and (since CSD wants to say that a person’s body is a proper part of him) that the soul and body together think. But HD does not say that the soul is a complete substance in its own right, and it does not say that the soul is a res cogitans. The soul is rather the substantial form of a substance (namely the living human body), that by virtue of which a human being carries out his distinctive activities -- not only thinking, but also seeing, hearing, digesting, walking, and so on. And it is the human being as a whole which does these all of these things (including thinking) while a person is alive, and not the soul alone which does them.
Now Bill’s comparison between CSD and HD is in my view mistaken, for I think he fails to take seriously enough the HD conception of the soul as a kind of form. For CSD, the soul is a complete substance in its own right, and specifically a substance that thinks (res cogitans). That is why CSD seems to lead both to the conclusion that the soul alone thinks (since the soul just is a thinking substance) and (since CSD wants to say that a person’s body is a proper part of him) that the soul and body together think. But HD does not say that the soul is a complete substance in its own right, and it does not say that the soul is a res cogitans. The soul is rather the substantial form of a substance (namely the living human body), that by virtue of which a human being carries out his distinctive activities -- not only thinking, but also seeing, hearing, digesting, walking, and so on. And it is the human being as a whole which does these all of these things (including thinking) while a person is alive, and not the soul alone which does them.
What leads Bill astray here is the HD claim that the soul persists beyond the death of the body and can think when it does so. He apparently supposes that the way in which the soul thinks after death is the same as the way in which it thinks when conjoined to the body. And since the way in which it thinks after death is (obviously) to do so independently of the body, this would seem to entail that HD is implicitly committed to the view that the soul thinks independently of the body even when it is conjoined to it, notwithstanding the official HD stance that only body and soul together think. But in fact HD explicitly denies that the soul thinks after death in the same way that it does when conjoined to the body. For our intellectual powers only operate when we are alive because of the data we get from the senses and the mental imagery this gives rise to; as Aquinas says, “the soul united to the body can understand only by turning to the phantasms” [where for the sake of simplicity a “phantasm” can be thought of, roughly, as a mental image] (Summa Theologiae I.89.1). That is its natural mode of carrying out intellectual operations. And for HD, sensation and imagination, unlike intellect, have a material basis. (This is why for HD neural activity is -- as I have explained in a previous post -- a necessary condition of everyday cognitive activity despite the immateriality of the intellect, even if it is not a sufficient condition.) Hence, while we are alive it is only body and soul together which think, and not the soul alone.
Now, after death the soul no longer has available to it its normal input from sensation and imagination. If it is to think while disembodied, then, it must do so in a very different manner. What this involves, for Aquinas, is “turning to simply intelligible objects” rather than to phantasms, as an angel (a wholly disembodied intelligence) would. (Think of pure concepts divorced from sensation or imagination.) And this entails a difference as well in the kinds of things the intellect can know after death. As George Klubertanz says in a once widely-used manual of Scholastic philosophy:
Knowledge of singular material things will be naturally impossible for the separated soul, and likewise existential judgments about material or sensible things. It will also be impossible to acquire knowledge of previously unknown material objects… On the other hand, in this life the soul has no actual direct knowledge of itself, because it is the form of a body. Once separated in death, it will be actually intelligible in itself, and so the soul will directly know itself as an actually existing singular spiritual substance… Communication between separated souls and between souls and angels should be possible, at least in so far as states of mind and will are concerned… Whatever other knowledge is necessary will be given by God, in a fashion similar to the mode of angelic knowledge. (The Philosophy of Human Nature, pp. 317-18)
To borrow and develop an analogy from an earlier post, you might think of the postmortem soul like a hand which has been severed from the body and which is not only kept alive artificially, but caused to move its fingers (and in this way to carry out something like its normal operations) via electrical stimulation of the muscles. The normal state of the hand is to be connected to and controlled by the body in such a way that it is the entire organism, and not the hand alone, that moves the fingers. But that does not entail that the hand might not also move them apart from the body, after being severed, by non-natural means. Similarly, the normal state of the intellect is to be connected to the body in such a way that it is the entire organism, and not the intellect alone, which thinks. But that does not entail that the intellect might not also think apart from the body, after death, by non-natural means.
Now, notice how different this is from the way a Cartesian res cogitans apparently operates. To be sure, while conjoined to the body, the res cogitans does gather information through the sense organs, just as a Thomistic soul does. But whereas for Aquinas the conscious processes associated with sensation and imagination are bodily in nature, for the Cartesian all consciousness resides in the immaterial res cogitans alone and the matter that makes up the brain is utterly devoid of consciousness. (Interestingly, and as I noted in an earlier post, it is not so clear that Descartes himself -- who never entirely escaped his Scholastic inheritance -- put imagination on the res cogitans side of the divide between mind and body. But if we think of imagination as a conscious process, then his position would entail that it resides entirely in the res cogitans. And Descartes did of course notoriously deny that animals are conscious, precisely because they are material. For the Thomist, who does not share Descartes’ entirely mathematicized conception of matter, there is no difficulty in attributing consciousness to animals despite their being purely material.)
Since cognitive and conscious activity alike reside, for the Cartesian, entirely in the res cogitans, the soul continues to operate in pretty much the same manner after death as it did before death. Hence we get scenarios like W. D. Hart’s “seeing without a body” example (which I discussed in a previous post) on which the soul enjoys conscious perceptual experiences of just the sort we have in everyday life, only without any bodily processes whatsoever. For the Thomist, this is impossible, at least naturally. A disembodied soul, lacking the sensations and mental imagery that the body alone makes possible, simply could not have, on its own, the kind of experience Hart describes.
Now the Cartesian position does not make much sense, in my view. Precisely because it puts sensation and imagination on the side of the body, HD has (as I noted in an earlier post) a much easier time than the Cartesian does in assimilating what we know from modern neuroscience. Bill seems to think the Cartesian view is much clearer than the Thomistic one, but in fact I think it is very much the other way around. Aquinas’s position is a carefully worked out attempt to resolve the ambiguities in Aristotle’s approach and to capture, in the process, the middle ground between substance dualism and materialism -- to do justice both to the immateriality of the intellect that is revealed by philosophical argument, and to the tight relationship between mental processes and bodily ones that is revealed by experience. Descartes’ position, by contrast, is an ad hoc attempt to fit the immaterial mind into a novel, post-Scholastic mechanistic conception of the natural world -- an attempt which led to bizarre consequences like the interaction problem and the denial of consciousness to non-human animals.
Be that as it may, the point to emphasize here is that the features of CSD which imply that the soul alone thinks, and does so in the same manner whether or not it is conjoined to the body, are not present in HD. Thus HD is not open to the same objection that Bill raises against CSD. In particular, HD is not open to the charge that it implies two, contradictory, answers to the question “What is it that thinks?” When the soul is conjoined to the body, the composite of soul and body alone can be said to think. When the soul thinks on its own, it does so only when disembodied, and in a very different manner. Nor is this difference in manner an ad hoc device invented in order to avoid problems of the sort that afflict CSD. Rather, it follows naturally from the Thomistic understanding of cognition as naturally dependent on phantasms.
Bill also suggests a second line of criticism, which will be familiar from his earlier posts on HD:
But 'subsistent form' smacks of contradiction. How can a form be subsistent? To say that a form is subsistent is to say that [it] is a primary substance, that [it] is broadly logically capable of independent existence. But a form is precisely not a primary substance but a 'principle' invoked in the analysis of primary substances. Aquinas cannot do justice to his own insight into the independence of the intellect from matter from within the hylomorphic scheme of ontological analysis he inherits from Aristotle. This bolded (and bold) thesis is central to my critique of hylomorphic dualism. His metaphysica generalis is at war with his special-metaphysical insight into the independence of intellect from matter.
I have already addressed this criticism in the earlier posts in this series, but I want to say more about it here. First, and for reasons I have stated before, I don’t think Bill can or would claim that hylemorphism is inconsistent with the notion that some forms might exist apart from matter. (Indeed, in his most recent post he seems willing to allow at least for the sake of argument that a hylemorphist could conceive of God, though immaterial, as “pure form, the ‘form of all forms.’”) Nor, as I have also noted before, is it correct to characterize HD as committed to forms existing all by themselves, without qualification. Rather, for HD a form that exists apart from matter (whether an angel or a disembodied human soul) is always a form together with an “act of existing” (precisely because, as Bill implies, a form all by itself would be a mere abstraction). So, Bill’s beef can only reasonably be with the idea that the form of a material thing, specifically, could exist apart from the matter that informs it, even as an incomplete substance conjoined to an act of existing.
But why this is supposed to be problematic is not at all clear once these qualifications have been made. One way it might seem problematic is if we think of the form of a material thing as a kind of shape or spatial configuration. If we thought of it that way, then when HD characterizes the soul as persisting beyond the death of the body, it might sound like it is claiming that a shape or spatial configuration can persist when the matter that filled in the shape or the parts which were configured have disappeared. And that does indeed sound incoherent. But in fact a form (as that term is being used in the present context) is not a shape or a spatial configuration. When HD says that the soul is the substantial form of the living human body, what it means is that the soul is that which gives a human being his nature or essence, and thus that by virtue of which a human being carries out his distinctive activities -- thinking, willing, seeing, hearing, digesting, reproducing, walking, and so on.
Now, Bill presumably would allow that there is nothing incoherent in the notion of such a nature or substantial form -- that is, in the notion of a thing which by virtue of its nature carries out both material and immaterial operations. There is, at any rate, nothing obviously incoherent in the notion. (Consider P. F. Strawson’s famous analysis of a person as something to which both material and mental predicates apply. Presumably Bill would allow that that analysis is coherent, and if we add to it the notion that mental predicates refer to immaterial attributes -- which Bill could have no problem with, since he sympathizes with dualism broadly conceived -- then we have the notion of a kind of thing which has both material and immaterial features.)
But Bill would still object to the notion of such a thing carrying out its immaterial operations entirely apart from matter. But why? As I have noted before, there is nothing incoherent in saying both that dogs by virtue of their nature have four legs and that this particular dog only has three legs because (given injury or genetic defect) it is not in its natural state. There is nothing incoherent in saying both that moving the fingers is normally something done only by the entire person, rather than the hand alone and that this particular hand is moving its fingers apart from the body because (given that it has been severed but artificially preserved) it is not in its natural state. So why should there be anything incoherent in saying both that normally it is only the soul and body together which think and that this particular soul is thinking apart from the body because (given the death of the body) it is not in its natural state?
Again, it would be no good for Bill to object “But how could a form subsist all by itself, given hylemorphism?” The answer to that, as we’ve seen, is that no one says in the first place that the soul subsists all by itself; rather, it subsists, like the forms of purely immaterial substances do, together with an act of existing. “But how could the form of a material thing do so?” The answer is that the form of a purely material thing could not do so, but that the human soul is not the form of a purely material thing, but rather of a thing with both material and immaterial operations. It is because of the latter that the human soul can persist beyond the death of the body; it is only the latter that it can carry out when separated from the body; and it necessarily does so in a very different way from the way it did while conjoined to the body. So, again, what exactly is the problem?
Bill also calls attention to an earlier post of his which criticizes the HD approach to the interaction problem. I’ll address that in a future post.
