Some brief arguments for dualism, Part I

It is unreasonable to expect even the best argument for a controversial philosophical position to be capable, in one fell swoop and all by itself, of convincing the most skeptical opponent – or, indeed, even to move him slightly in the direction of reconsidering his position. That is (usually, anyway) simply not how the human mind works. A dispute over some particular argument for the existence of God, mind-body dualism, or traditional sexual morality (to take just three examples) can reflect a tacit disagreement about fundamental metaphysical assumptions that is so deep and unconscious that the parties to the dispute (or at least one party, usually the skeptical or “naturalist” one) are barely aware that it exists at all, and often talk past each other as a result. What seems like an obvious objection to an argument can often constitute in reality a failure to see the point of the argument, and in particular a failure to see that what the argument does is precisely to call into question the intelligibility or rational justifiability of the objection itself. While the argument in question can in many cases be stated fairly simply and straightforwardly, pages and pages, indeed an entire book, might be required in order to set the stage so that its terms and basic assumptions are properly understood, and that countless point-missing objections might patiently be swept away like so much intellectual rubbish standing in the way of understanding.

Some common objections to dualism are like this. They falsely assume, for example, that any argument for dualism must be something analogous to a “God of the gaps” argument – a “soul of the gaps,” as it were – which seeks to exploit some current lacuna in our knowledge of the brain and to suggest that the “hypothesis” of an immaterial substance might explain what neuroscientists have so far been unable to. It is then objected that such an explanation would violate Ockham’s razor, that neuroscience has already “explained” x, y, and z and thus can be expected to explain everything else, etc. etc. I hear these objections frequently. They are often presented by people who mean well, and who are not entirely uninformed about some of the arguments presented by both materialists and anti-materialists in the philosophy of mind. But they nevertheless reflect a very shallow understanding of the debate. For the main arguments for dualism do not have this structure at all. They are not quasi-scientific “explanatory” “hypotheses” which “postulate” the existence of this or that as one way among others (albeit the most “probable”) of “accounting for” “the evidence.” They are intended rather as strict metaphysical demonstrations. They either prove conclusively that the mind is immaterial or they prove nothing. And if they work, there can be no question of the materialist looking for other possible ways to explain “the data.” For the existence of an immaterial mind, or an immaterial aspect to the mind, will, given such a proof, simply have itself to be taken as a piece of data for which any acceptable theory has to account.

Again, this doesn’t mean that one should judge such arguments based on one’s immediate reaction to a first reading; to prove something conclusively doesn’t mean to prove it instantly, to the immediate satisfaction of the most hostile and stubborn skeptic. Even properly understanding an argument, especially in metaphysics, can require a great deal of effort and sustained thought. Still, some dualist arguments are straightforward enough that at least their basic thrust can be put fairly succinctly, even if a complete treatment would require various further explanations of this or that premise or key concept. In this post and several succeeding ones I want to present some of these arguments, in as brief a form as possible. (Further elaboration can be found in my books Philosophy of Mind and The Last Superstition.)

One aspect of the mind that philosophers have traditionally considered particularly difficult to account for in materialist terms is intentionality, which is that feature of a mental state in virtue of which it means, is about, represents, points to, or is directed at something, usually something beyond itself. Your thought about your car, for example, is about your car – it means or represents your car, and thus “points to” or is “directed at” your car. In this way it is like the word “car,” which is about, or represents, cars in general. Notice, though, that considered merely as a set of ink marks or (if spoken) sound waves, “car” doesn’t represent or mean anything at all; it is, by itself anyway, nothing but a meaningless pattern of ink marks or sound waves, and acquires whatever meaning it has from language users like us, who, with our capacity for thought, are able to impart meaning to physical shapes, sounds, and the like.

Now the puzzle intentionality poses for materialism can be summarized this way: Brain processes, like ink marks, sound waves, the motion of water molecules, electrical current, and any other physical phenomenon you can think of, seem clearly devoid of any inherent meaning. By themselves they are simply meaningless patterns of electrochemical activity. Yet our thoughts do have inherent meaning – that’s how they are able to impart it to otherwise meaningless ink marks, sound waves, etc. In that case, though, it seems that our thoughts cannot possibly be identified with any physical processes in the brain. In short: Thoughts and the like possess inherent meaning or intentionality; brain processes, like ink marks, sound waves, and the like, are utterly devoid of any inherent meaning or intentionality; so thoughts and the like cannot possibly be identified with brain processes.

You can, as I have implied, look at this as just a “puzzle” for materialism – one which might be solved by developing a complex functional analysis of mental states, or by framing materialism in terms of the concept of “supervenience” rather than identity or reduction, or whatever. Or you can see it as a very simple and straightforward statement of an objection that, while it can also be formulated in much more sophisticated and technical terms and in a way that takes account of and preempts the various objections materialists might try to raise against it, nevertheless goes to the core of the problem with materialism, and indeed shows why materialism cannot be true. This latter view is the one I endorse. I maintain that the problem for materialism just described is insuperable. It shows that a materialist explanation of the mind is impossible in principle, a conceptual impossibility. And the reason has in part to do with the concept of matter to which materialists themselves are at least implicitly committed. Some of the further posts in this series will develop this suggestion. Along the way we will see (among other things) that the common materialist claim that “everything else has been explained in materialist terms” is an urban legend, based on nothing more than conceptual sleight of hand coupled with historical ignorance. Stay tuned.

Some brief arguments for dualism, Part V

The next argument in our series is inspired by Karl Popper, and in particular by some ideas he first presented in his short article “Language and the Body-Mind Problem” (available in his collection Conjectures and Refutations) and repeated in The Self and Its Brain. As Popper originally formulated it, its immediate aim was to demonstrate the impossibility of a causal theory of linguistic meaning, but it is evident from some remarks he once made about F. A. Hayek’s book The Sensory Order that he also regarded it as a refutation of any causal theory of the mind. (See my essay “Hayek the Cognitive Scientist and Philosopher of Mind” in The Cambridge Companion to Hayek.) Hilary Putnam would later present a similar line of argument in his book Renewing Philosophy, though he does not seem to be aware of Popper’s version.

The argument as I will state it is somewhat different from anything either Popper or Putnam has said, though it is in the same spirit. Before stating the argument, it is worthwhile recalling the “mechanistic” conception of the natural world which, as I have emphasized in earlier posts in this series, implicitly or explicitly informs materialism. On this conception, the world is devoid of what Aristotelians call formal and final causes: there are in nature no substantial forms or inherent powers of the sort affirmed by the medieval Scholastics, and there is no meaning, purpose, or goal-directedness either. The physical world is instead composed entirely of inherently purposeless elements (atoms, corpuscles, quarks, or whatever) governed by inherently meaningless patterns of cause and effect. All the complex phenomena of our experience, from grapes to galaxy clusters, from mudslides to minds, must somehow be explicable in terms of these elements and the causal regularities they exhibit.

But in fact there can be no such explanation of the mind, not even in principle. In particular, there can be no such explanation of intentionality, the mind’s capacity to represent the world beyond itself – as it does, say, when your thought that the cat is on the mat represents the cat’s being on the mat.

The reason is this. As already indicated, any materialistic explanation of intentionality is bound to be a causal explanation. That is to say, it is going to be an attempt to show that the intentionality of a mental state somehow derives from its causal relations. The causal relations in question might be internal to the brain (as they are according to “internalist” theories of meaning); they might extend beyond the brain to objects and events in a person’s environment (as they do according to “externalist” theories); they may even extend backwards in time millions of years to the environment in which our ancestors evolved (as they do according to “biosemantic” theories). An adequate description of the relevant causal relations may require any number of technical qualifications (such as an appeal to Fodor’s notion of “asymmetric dependence”). In every case, though, a materialist is bound to appeal to some pattern of causal relations or other as the key to explaining intentionality. He’s got nothing else to appeal to, after all; the basic elements out of which everything in the physical world is made are by his own admission devoid of any meaning (“intentionality simply doesn’t go that deep,” as Fodor insists in Psychosemantics) and anything other than these elements exists only insofar as causal interactions between the elements generates it.

Now, specifying the relevant causal relation entails specifying a relevant beginning point to the series and a relevant end point. We have to identify some physical phenomenon as that which does the representing, and some other physical phenomenon as that which is represented; or in other words, we have to pick out one thing as the thought, and another thing as that which is thought about. To take a simple example, if we imagine that a certain brain process is associated with the thought that the cat is on the mat because it is caused in such-and-such a way by the presence of cats on mats, then we will have to take the cat’s presence on the mat as the beginning of the relevant causal chain (call it A) and the occurrence of the brain process in question (call it B) as the end. (Of course, specifying exactly what the “such-and-such a way” involves can get pretty complicated, as anyone familiar with the contemporary literature knows, but the complications are irrelevant for our purposes here.)

But what objective reason is there to identify A and B as “the beginning” and “the end” of a causal sequence? Consider what happens in a situation like the one in question. Someone flips on a light switch, which causes electrical current to flow through the wires in the wall up to a ceiling lamp. Light from the lamp travels to a cat sitting on a mat below, is reflected off of the cat, and travels to the retinas of a nearby observer. This in turn causes signals to be sent up the optic nerves to the brain, which results in the firing of a certain cluster of neurons, which in turn results in the firing of another cluster, which in turn results in the firing of yet another cluster, and so on and so forth. All this neural activity ultimately results in a behavioral response, such as walking over to the refrigerator to get the milk bottle out so as to give the cat a snack. And this is followed, say, by an accidental dropping of the milk bottle, which results in broken glass, a cut to the ankle, a yelp of pain, and the kicking of the cat.

Now, again, what is it about this complex chain of events that justifies picking out A and B specifically and labeling them “the beginning” and “the end” respectively? Why is it the cat’s presence on the mat that counts as “the beginning” – rather than, say, the flipping of the light switch, or the flow of the current to the ceiling lamp, or the arrival of such-and-such a photon at exactly the midpoint between the surface of the cat and the observer’s left retina? Why is it brain process B exactly that counts as “the end” of the causal chain – rather than, say, the brain process immediately before B or immediately after B, or the walk over to the refrigerator, or the motion of such-and-such a shard of glass from the broken milk bottle as it skips across the floor? Of course, we have an interest in picking out and identifying cats and not in picking out and identifying individual photons, and an interest in brain processes and their associated mental states that we don’t have in shards of glass. But that is a fact about us, not a fact about the physical world itself. Objectively, as far as the physical world itself is concerned, there is just the ongoing and incredibly complex sequence of causes and effects, which extends indefinitely forward and backward in time well beyond the events we have described. Objectively, that is to say, there is no such thing as “the beginning” or “the end,” and nothing inherently significant about any one event as compared to another.

Popper’s point, and Putnam’s, is that what count as the “beginning” and “end” points of such a causal sequence, and thus what counts as “the causal sequence” itself considered in isolation from the rest of the overall causal situation, are interest relative. These particular aspects of the overall causal situation have no special significance apart from a mind which interprets them as having it. But in that case they cannot coherently be appealed to in order to explain the mind. It is no good saying that the representational character of our mental states derives from their causal relations when the causal relations themselves cannot be specified except in terms of how they are represented by certain mental states. A vicious circularity afflicts any such “theory” of intentionality.

Now it is important to emphasize that the point is not that causation per se is interest relative or mind-dependent; the argument is not an exercise in idealism or anti-realism. The overall complex ongoing sequence of causes and effects is entirely mind-independent. The claim, again, is just that something’s counting as a “beginning” or “end” point within the series is interest-relative and mind-dependent. Still, even this much might seem to be too close to idealism or anti-realism for comfort. It might seem to make causal explanations somehow subjective and arbitrary. (Indeed, Putnam attributes something like this sort of objection to Noam Chomsky.) But to fear that the Popper/Putnam argument we’ve been considering might entail that causal explanations are somehow subjective or arbitrary doesn’t show that the argument is wrong.

Is there any way to reconcile the argument with the objectivity and non-arbitrariness of causal explanations? Absolutely. The way to do it is to show that certain physical phenomena really can objectively count as the beginning or end points of a causal sequence after all – that they can indeed be picked out in a way that is not mind-dependent or interest-relative. But how can that be done? By showing that natural objects and processes are by their natures inherently directed towards the generation of certain other natural objects and processes as an “end” or “goal.” That is to say, by showing that natural objects and processes have what Aristotelians call substantial forms and final causes. In short, the way to explain how causal explanations can be objective and non-arbitrary as opposed to subjective and interest-relative is to acknowledge that the mechanistic conception of the world is mistaken, and that the Aristotelian-Scholastic conception that it replaced is correct after all.

So, the Popper/Putnam argument shows that the mechanistic conception of nature to which materialists are explicitly or implicitly committed entails that there can be no materialistic explanation of the mind. (As we have seen in earlier posts in this series, other arguments tend to show the same thing.) And the only way to sidestep the argument is to abandon the mechanistic conception of nature, which entails rejecting materialism anyway. Either way, materialism is refuted.

What positive view results? That depends. If one holds on to the mechanistic conception of nature, the result would seem to be some broadly Cartesian form of dualism – either substance dualism or property dualism. (Popper himself opted for the former. Putnam does not consider what consequences his view might have for the dualism/materialism debate.) If instead on opts to return to an Aristotelian conception of nature – the right choice, in my view – then one is on the path toward hylemorphic or Thomistic dualism. (I examine these options in my book Philosophy of Mind and defend the latter at length in The Last Superstition.)

Hence, one way or the other dualism is vindicated. And as with the arguments presented in earlier posts in this series, it will not to do object to this one that it somehow “violates Ockham’s razor,” that materialism is the “simpler explanation,” and so forth. Such objections can only have force against attempts to present dualism as a “probable” “hypothesis” “postulated” as the “best explanation” of the “data.” That is not the sort of argument I have given. As I have already said, the argument just presented is an attempt to show that materialism fails in principle; it purports to be a metaphysical demonstration of the falsity of materialism, not a piece of quasi-empirical theorizing. If it fails (and obviously I don’t think it does), it does not fail for the sorts of reasons empirical hypotheses do.

Nagel and his critics, Part IX

Returning to my series on the critics of Thomas Nagel’s Mind and Cosmos, let’s look at the recent Commonweal magazine symposium on the book.  The contributors are philosopher Gary Gutting, biologist Kenneth Miller, and physicist Stephen Barr.  I’ll remark on each contribution in turn.

Animals are conscious! In other news, sky is blue, water wet

A reader calls my attention to a Discovery News story which breathlessly declares: 

A prominent group of scientists signs a document stating that animals are just as “conscious and aware” as humans are.  This is a big deal.

Actually, it is not a big deal, nor in any way news, and the really interesting thing about this story is how completely uninteresting it is.  Animals are conscious?  Anyone who has ever owned a pet, or been to the zoo, or indeed just knows what an animal is, knows that.  

OK, almost anyone.  Descartes notoriously denied it, for reasons tied to his brand of dualism.  And perhaps that is one reason someone might think animal consciousness remarkable.  It might be supposed that if you regard the human mind as something immaterial, you have to regard animals as devoid of consciousness, so that evidence of animal consciousness is evidence against the immateriality of the mind and thus a “big deal.”  This is not what the article says, mind you, but it is one way to make sense of why it presents the evidence of animal consciousness as if it were noteworthy.

Vallicella on hylemorphic dualism, Part III

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.

Stoljar on intentionality

Daniel Stoljar’s new book Physicalism is a very useful overview of its subject. However, its brief treatment of intentionality (and of some other topics too) evinces a deep misunderstanding of dualism, a misunderstanding that seems to be very common in contemporary philosophy of mind.

Stoljar begins his discussion with the following characterization of intentionality:

The intentionality of a mental state is its aboutness. When I think of Vienna or believe that the computer is on the desk or fear that the planet will get hotter, I instantiate mental states which are in a hard to define sense about Vienna, or the computer on the desk or planet Earth. The idea is that mental states (and speech acts) have a property rather like signs, sentences, and gestures; that is, they are about or represent things other than themselves. (p. 200)

So far so good; at least, that is an accurate characterization of what modern philosophers, whether physicalists, dualists, or idealists, tend to mean by “intentionality.” (Whether they are right to think of it this way is a question I will return to later.) Stoljar then suggests that the reason intentionality is philosophically problematic is that it is supposed to involve a relation that might hold between a thinker and something else, and yet lacks three key features one would expect such a relation to have. First, if I bear a relation to something else, one would expect that that something else exists; and yet I can think about something that does not exist (e.g. Valhalla). Second, if I bear a relation to something else, one would expect that there is some particular thing I bear it to; but I can think about a man without there being some man in particular I am thinking of. Third, if I bear a relation to some thing A and A = B, then one would expect that I thereby bear that relation to B; but if I am thinking about Vienna, then even though Vienna is the birthplace of Schubert, it doesn’t follow that I am thinking about the birthplace of Schubert, about whom I may know nothing. (To use the technical jargon, ascriptions of intentional mental states are often non-extensional or intensional, insofar as we cannot always substitute co-referring expressions salve veritate; that is to say, intentionality-with-a-t is often – though, it is important to note, not always – associated with intensionality-with-an-s.)

Now, Stoljar acknowledges that these features of intentionality are philosophically puzzling. But he claims that they pose no special difficulty for physicalism. In particular, they give us no reason to favor dualism over physicalism, for they are as problematic on the former view as on the latter. Says Stoljar: “[S]uppose classical dualism is true and I am some sort of complex of an ordinary physical object and soul; it is still impossible for me to stand in a relation to things that don’t exist! In sum, the paradoxes of intentionality will remain whether physicalism is true or not, hence they do not concern physicalism.” (p. 201)

There are two problems with this. First, it does not get to the heart of the problem of intentionality. Second, it rests on a misunderstanding of dualism. Let’s take them in order.

Consider the following dialogue:

Policeman: Ma’am, some bad news, I’m afraid. Your son just robbed a liquor store. Caught him red-handed with the cash tucked in the glove compartment, along with a few bottles of Tanqueray, vermouth, and tipsy olives that he tossed in the back seat.

Mom: Oh dear. I suppose he’s in trouble for being under 21. Or was he speeding in the getaway car?

Policeman: Well, there is that, I guess. But here’s the main thing: He robbed a liquor store.

Stoljar reminds me a little bit of Mom. Yes, the “paradoxes of intentionality” that he calls attention to are important. But it is intentionality itself, and not the “paradoxes,” that is of the greatest interest. Even if the objects I thought about always existed, or were always particular, or never generated non-extensional contexts – that is to say, even if intentionality exhibited none of the “paradoxical” features in question – the “aboutness” of my thoughts would remain. And it is that “aboutness” that the dualist takes to pose the chief difficulty for physicalism.

There are at least two ways to see how – a commonsense way and a more technical way. The commonsense way is this. Consider the word “cup” as you might write it in ink. Now consider a set of splotches that forms after your ink bottle leaks overnight, among which there are three right next to each other that by chance look vaguely like this: CUP. The set of splotches looks like the word, but it isn’t. The word has meaning, the splotches do not. But this has nothing to do with the physical properties of either. The ink is the same in both cases, as are the shapes. We can even imagine a case where your penmanship is bad enough and/or the splotches are distinct enough that their appearance is indistinguishable from the word “cup” that you’ve written. In general, it is not the intrinsic physical properties of letters, words, and sentences, whether written or spoken, that give them the meaning they have. Rather, their meaning derives from the conventions established by language users. It is an accident of history that the sequence of shapes cup has meaning and the sequence of shapes - ( ^ does not. Intrinsically, the first sequence is as meaningless as the second. But what is true of ink splotches and sounds seems no less true of all other physical phenomena. They all seem obviously devoid of meaning until someone decides to use them to convey meaning. As John Searle puts it, words, sentences, and the like, considered as material objects, have only “derived intentionality.” We are able to impart meaning to them by virtue of having thoughts with “original intentionality” – your thought about a cup represents or means cup without anyone having to form a convention of using it to mean that. But if neural processes are as devoid of original intentionality as ink marks, sounds, and the like, then it is hard to see how thoughts could be identified with neural processes, or claimed to supervene upon them. And the same is true of any other purported physicalistic basis for mental phenomena.

Now, there are various things a physicalist might want to say in response to this, but the point is that the problem intentionality is claimed to pose for physicalism here can obviously be stated in a way that makes no reference to the “paradoxes of intentionality.” If the commonsense point just made constitutes a difficulty for physicalism, it would do so even if the paradoxes in question did not exist.

The more technical way of making the point is to emphasize that the conception of “the physical” that physicalism typically presupposes is a mechanistic one – that is to say, one which (as I have discussed ad nauseam, e.g. here) takes matter to be devoid of any immanent or intrinsic final causality or teleology of the sort affirmed by the Aristotelian-Scholastic tradition the early moderns sought to overthrow. For the Scholastics, efficient causes in the natural order inherently “point to” or are “directed at” their effects, and in sweeping aside immanent final causality the moderns rejected the claim that any natural phenomenon inherently and irreducibly “points to” or is “directed at” anything at all. Intrinsically, the natural world is for them comprised instead of “nothing but” meaningless, purposeless particles in motion or the like. (Descartes, Locke, Boyle, Newton, and other early mechanists did of course think of ends or goals being imposed on the world by God, but precisely because they were mechanists opposed to Aristotelianism and Scholasticism, they saw the resulting purposes or meanings as extrinsic to the world rather than inherent. See the great many posts on this theme that I’ve written over the last several months, as well as the discussions in The Last Superstition and Aquinas.)

Now, if intentionality involves something “pointing to” or being “directed at” or “about” something beyond itself, and the mechanistic conception of matter underlying physicalism holds that there is no such thing in nature as something inherently and irreducibly being “directed at” or “pointing to” something else, then it seems at the very least difficult to see how intentionality could possibly be something material or physical. I had reason to make this point in my recent post on Chomsky. But though Stoljar quotes the same passage from Jerry Fodor that I cited there, he does not see (as Fodor does, though Fodor does not make explicit reference to the anti-Aristotelian mechanistic revolution) that it is the moderns’ own conception of matter, rather than the “paradoxes of intentionality,” that generates the difficulty.

Again, the point is not that the physicalist might not have a good response to points like the ones I’ve been making – I don’t think so, but that’s another issue. The point is rather that it misses the point to address the problem of intentionality as if the paradoxes Stoljar calls attention to were at the heart of it, and as if it had nothing to do with the nature of “the physical.” Both the commonsense point and the technical point (as I have called them) show that the problem has very much to do with the nature of the physical, and nothing essentially to do with the paradoxes.

But how, the physicalist might still ask, does dualism fare any better? For as Stoljar suggests, wouldn’t any objection to a physicalist account of intentionality apply mutatis mutandis to any dualist alternative? Or as Clayton Littlejohn once objected in a remark in Victor Reppert's combox: “It seems like causal pathways in an immaterial substance would have the same content fixation problems as causal pathways in a physical substance.”

As I have said, this sort of objection seems increasingly common in contemporary philosophy of mind, but it is deeply confused. What dualist ever said anything about “causal pathways in an immaterial substance”? Stoljar and Littlejohn seem to think that what the dualist means by an immaterial substance or soul is something that is just like a material substance – and in particular, something with distinct and causally interrelated parts – only not material, but instead “made out of” some other kind of “stuff” (“ectoplasm” maybe). In short, a kind of ghostly machine, but a machine all the same. But that is precisely what dualists – whether of a Platonic, Thomistic, or Cartesian stripe – do not think the soul is. For dualists have typically held that the soul is simple or non-composite, and thus not “made out of” causally interrelated parts of any sort. That its activities cannot be modeled on those of a material substance is the whole point.

How should we think of it, then? For the Cartesian, the essence of the soul is thought, and that is the entirety of its essence. Descartes does not say: “Gee, it’s hard to see how intentionality could be explained in terms of causal relations between physical parts. I therefore postulate an immaterial substance with immaterial parts whose causal relations are capable of generating thought and intentionality.” That would imply that in addition to thought, a soul has of its nature the various parts in question and their characteristic interrelations. And that is just what Descartes denies. A Cartesian immaterial substance doesn’t generate thinking. It is thinking, and that is all that it is. For that reason, and contrary to what Stoljar assumes, the Cartesian conception of intentionality cannot possibly be open to the same objections raised against physicalism. To say “Maybe a Cartesian immaterial substance – that is to say, something which just is its activity of thinking – could, like a physical substance, exist in the absence of intentional mental states” is just incoherent. A physicalist might want to raise some other objection to the Cartesian view, but Stoljar’s tu quoque is not open to him.

Now, for the Thomistic or hylemorphic dualist, the soul is to be understood, not as pure thought, but rather as the substantial form of the living human body. And qua form, it is not a complete substance in the first place, much less a material or quasi-material one. (Talk of the soul as an “immaterial substance” is thus for the Thomist at least misleading, though he does hold that the soul subsists beyond the death of the body as an incomplete substance.) Here too, though, talk of interrelated quasi-material parts, “causal pathways,” and the like is completely out of place. But for the Thomist, the Cartesian’s talk of inner “representations” is out of place too; as I have discussed elsewhere (e.g. here and here) the “representationalist” conception of the mind is an essentially modern one that the ancients and medievals generally would have rejected. As a consequence, the ancients and medievals would reject too the essentially modern way of framing the issue of intentionality that I have, for the sake of argument, been following up to now in this post. For instance, if a broadly Aristotelian-Thomistic conception of nature is correct, then natural phenomena really do have intrinsic final causes after all, so that (for example) material efficient causes inherently “point beyond” themselves to their effects. It would follow that a thought’s “pointing beyond” itself cannot be what makes it immaterial; and indeed, that is not the sort of argument the ancients and medievals gave for the mind’s immateriality. (Nor did they argue from “qualia” – that too, as I have noted many times before, is a very modern sort of argument for dualism, and presupposes a mechanistic approach to nature.) The ancients and medievals focused instead on such features of our thoughts as their universality and determinacy, which they took to be essentially incompatible with thought’s having any material organ. (See here, here, chapter 4 of Aquinas and chapter 7 of Philosophy of Mind.)

But that is a gigantic topic of its own. Suffice it for present purposes to note that with respect to Thomistic dualism no less than the Cartesian version, contemporary physicalists would do well to try better to “know their enemy” before dismissing him.

[For more on this theme, see my posts on Paul Churchland and dualism, here, here, and here.]

Descartes’ “clear and distinct perception” argument

The “clear and distinct perception” argument is one of two arguments for mind-body dualism Descartes gives in the sixth of his famous Meditations on First Philosophy. It can be summarized as follows:

1. Whatever I have a clear and distinct idea of is capable of existing just as I understand it, at least in principle (e.g. if God creates it that way).

2. I have a clear and distinct idea of myself as simply a thinking, non-extended thing.

3. I have a clear and distinct idea of my body as simply an extended, non-thinking thing.

4. So I and my body are capable, at least in principle, of existing apart from each other.

5. So I am distinct from my body.

Does the argument work? Most contemporary philosophers would say No. I would say No and Yes and No.

Huh? Bear with me.

Here’s the first “No” part. For one thing, Descartes is, by all accounts, wrong to think of extension as the essence of matter, and thus as the essence of the human body. From an Aristotelian-Thomistic perspective (which is my perspective) there is obvious reason to reject this view, since A-T rejects the entire modern mechanistic conception of matter of which it is just a variation. But even those who accept this mechanistic conception – which includes almost all contemporary philosophers, even if (usually) only implicitly and unreflectively – would allow that “extension” (i.e. those properties of matter which can be defined geometrically, more or less) is too crimped a way of spelling out the mechanistic idea. They would allow all sorts of other mathematically quantifiable properties to feature in our characterization of matter as well. (What they share with Descartes is the insistence that, whatever matter is, formal causes and, especially, final causes will simply not be allowed to count as part of the material world.)

For another thing, A-T would also obviously reject Descartes’ implied assimilation of the self to the mind. Though the mind (specifically the intellect) is immaterial, “I” am nevertheless not distinct from my body from the A-T point of view, certainly not without serious qualification. In fairness to Descartes, he did not – contrary to the standard caricature (one now being vigorously combated by Descartes scholars) – actually hold that the body is non-essential to a human being, as if we were all really just ghosts trapped in machines (to allude to Ryle’s famous parody). He explicitly denies that “I” am in my body the way a pilot is in a ship, as if the body were an inessential excrescence. On the contrary, he believed that soul and body form a kind of organic unity, that a human being was an irreducible composite of the two, having attributes (namely appetites, emotions, and sensations) which cannot be predicated of either the soul alone or the body alone. The trouble is that, having abandoned the Aristotelian idea that the soul is the form of the body, and emphasizing as he does that it is the ego itself (and not just some part of the person) which is distinct from the body, he had a devil of a time explaining just how such an organic unity was possible. Hence it is no surprise that the “ghost in the machine” conception of human nature came to be seen as paradigmatically Cartesian, whatever Descartes’ own intentions. (Notoriously, what a thinker wants to conclude is not always what his premises actually imply.)

So, to the extent that Descartes’ argument depends on these assumptions, it is open to criticism. But it can fairly easily be fixed up to avoid these problems. For “myself” in step 2 and “I” in steps 4 and 5, just read “the mind” or (more exactly – and as we’ll see in a moment, as much in line with Descartes’ understanding of the mind as with the A-T view) “the intellect.” For “extension” just plug in either the Aristotelian view of matter or your favorite mechanistic conception. (It makes no difference for this specific argument.) Even if the resulting argument does not get us to precisely Descartes’ brand of dualism, it will definitely get us to some form of dualism, if it is otherwise unobjectionable.

Is it otherwise unobjectionable? Here we come to the “Yes” part of my initial reply. The main objection contemporary philosophers have to Descartes’ argument concerns its second premise, and it is an objection Hobbes raised in the Third Set of Objections to the Meditations. Even if it is conceded that Descartes has a clear and distinct idea of himself as a thinking thing, how can he be so sure that that which is doing the thinking is non-extended or, more generally, non-corporeal? The fact that he doesn’t conceive of corporeality when he conceives of thinking doesn’t show that thinking isn’t corporeal, any more than conceiving of triangularity without conceiving of trilaterality shows that something could be triangular without being trilateral.

So, Descartes needs some way of showing that thought can occur in the absence of anything corporeal or bodily. How about (after the fashion of some contemporary dualists) an appeal to metaphysical possibility, in particular to possible worlds? As in: “It is metaphysically possible for the mind to exist apart from the body” or “There is at least one possible world where mind exists apart from the body”? Nix that. From an A-T point of view, anyway, while these statements are perfectly true, they presuppose dualism and thus cannot be used to establish it. You cannot know what is possible for a thing, or what it might be like in various possible worlds, until you know its nature or essence. (Contemporary philosophers who try to define essence in terms of possible worlds thus have things backwards.) Hence, you cannot assert that there is a possible world in which mind exists apart from body, or that it is metaphysically possible for mind to exist apart from body, until you know the mind’s nature. And its nature is exactly what the Hobbesian objection calls into question.

A better way to show that thought can be incorporeal is just to show that it cannot be corporeal. This is a better way for two reasons. First, it establishes an even stronger claim than the one in question – always nice work if you can get it. Second, it is easy to do.

The reason is one we have examined in several earlier posts (such as this one). The objects of the intellect are abstract concepts, which are universal rather than particular, and determinate or exact rather than indeterminate or inexact. And the thoughts in which these concepts feature are (at least often) as universal, determinate, and exact as the concepts themselves. Yet nothing material has or can have these characteristics. Material objects and processes are inherently particular rather than universal, and also inherently indeterminate or inexact. Hence thoughts cannot possibly be identified with anything material. The point can be and has been developed at greater length (by writers like James Ross, and by me in The Last Superstition and Philosophy of Mind and in the earlier post just linked to) but the basic idea is fairly simple, is as old as Plato and Aristotle, and was endorsed and developed by various Scholastic writers.

The irony is that Descartes himself at least hints at this very argument when, earlier in the Sixth Meditation, he draws a rigid distinction between imagination on the one hand – which he apparently takes to be corporeal – and intellect on the other, which alone he identifies with the self he takes to be incorporeal. (The famous example of the chiliagon – which the intellect understands even though the imagination cannot form an image of it – is presented in this context.) This parallels the Aristotelian-Scholastic doctrine that intellect is immaterial while sensation and imagination are material. It is often supposed that Descartes assimilates sensation, imagination, and intellect into an amorphous something called “the mind,” but this is not the case. His view of their relationship is actually fairly close to that of his Scholastic predecessors. Here as elsewhere Descartes is, as contemporary Descartes scholars have made an industry of documenting, far more Scholastic than one would expect the Father of Modern Philosophy to be. (If only he had been consistently Scholastic, he would have really had something! – though he would not have had this claim to paternity. But we’d all have been better off, and Descartes could have spared himself a few millennia in purgatory.)

The thing is, once this Platonic-Aristotelian-Scholastic point has been developed in support of (our reformulated version of) premise 2, it more or less establishes dualism all by itself, so that the rest of the argument becomes otiose. Hence, Descartes’ argument works, but only if reformulated to such an extent that it amounts to little more than a restatement of an idea that had more or less already been around for millennia. The distinctively Cartesian bits – the stuff about “clear and distinct perception,” the assimilation of the self to the intellect, and the conception of matter as extension – are either wrong or irrelevant. So, as a Cartesian argument for dualism, the argument doesn’t really work after all. What is true in it isn’t new, and what is new isn’t true.

How typically modern!

Some brief arguments for dualism, Part III

In the previous post in this series, I argued that the “mechanistic” conception of the natural world adopted by the early modern philosophers more or less entails a kind of dualism insofar as its banishment of final causes from the material world effectively makes intentionality necessarily immaterial. Intentionality, of course, is one of two features of the mind to which contemporary philosophers of mind have paid special attention. The other is consciousness, and in particular the “qualia” that are said to make consciousness uniquely difficult to explain in material terms. There is a good reason for this difficulty – indeed, impossibility – and it is the same reason why intentionality is impossible to explain in materialistic terms. It lies in the mechanistic conception of matter itself.

The early modern philosophers and scientists were obsessed with quantification. There were several reasons for this, one of them being their desire to reorient intellectual efforts toward the improvement of life in this world and away from the otherworldliness of the ancients and medievals. This entailed a new emphasis on technology and more generally on the control and exploitation of the natural world in the interests of bettering man’s material condition. Since quantification would facilitate this, those aspects of nature that could be described in purely mathematical terms took on a special importance, and those which could not came to seem, from the point of view of this new, worldly approach to learning, irrelevant at best and a distraction at worst. Thus did final causes, hidden powers, substantial forms and the like go out the window. So too did the qualitative aspects of nature. Colors, odors, tastes, feels, sounds, and the like, at least as understood by common sense, vary from observer to observer – think of old philosophical chestnuts like the room temperature water that feels warm to one hand and cool to the other, colorblindness, and so forth – making them a poor fit for a science looking to make nature subject to human prediction and control. Out the window with them too, then. The physical world would be redefined as comprised of colorless, odorless, tasteless particles in motion; and color, temperature, and the like would be redefined entirely in terms of the quantifiable relations holding between these particles (e.g. heat and cold in terms of molecular motion). What about color, odor, taste, and so forth as common sense understands them? They in turn were redefined as entirely mind-dependent “secondary qualities” (or rather, ideas of secondary qualities), the ancestors of the contemporary philosopher’s concept of qualia. On the view in question, they do not exist in the physical world as it is in itself, but only in our perceptual representation of that world.

It should be obvious, then, how, as with intentionality, the notion that qualia are incapable of materialistic explanation is not some desperate attempt to avoid the implications of modern science, but is rather precisely a consequence of modern science. The mechanistic conception of matter that underlies science (or rather underlies what, since the 17th century, is allowed to count as science) itself entails that qualia (as we call them today) are immaterial or non-physical. Many early modern thinkers – Descartes, Cudworth, and Locke, for example – saw this, which is part of the reason they were dualists. Given the mechanistic conception of matter, these thinkers concluded that “secondary qualities,” “sensory qualities,” “qualia,” or whatever else you want to call them are necessarily immaterial, precisely because matter got (re)defined by the mechanical philosophy by contrast with these qualities.

Some contemporary naturalists – Joseph Levine, Thomas Nagel, and John Searle, for example – have more or less recognized this, acknowledging that there is nothing more to the contemporary materialist’s concept of matter (which derives from the 17th century “mechanical” conception) other than its contrast with the “qualitative” (and intentional) features of our experience of the world. Precisely for this reason, all three of these thinkers have (in their different ways) regarded modern materialism as deeply conceptually problematic, though they have also stopped short of embracing dualism. But other contemporary naturalists – Dennett and the Churchlands, for example, not to mention countless lesser lights of the sort who write crude atheist pamphlets and pop neuroscience books – cluelessly suggest that there is no good reason to think that the mind will fail to yield to the same sort of reductive explanation in terms of which everything else in nature has been accounted for.

In fact there is a very good reason why the mind should be uniquely resistant to such “explanation,” and it precisely because everything that doesn’t fit the mechanistic-cum-quantificational picture of the natural world has not been “explained” by science at all, but simply swept under the rug of the mind and treated as a mere “projection.” This is true in particular of anything in nature that seems to smack of final causality or to have an irreducible qualitative (as opposed to quantitative) character. It is conceptually impossible that the mind itself should be “explained” in the same way – that is to say, by further sweeping – which is why modern philosophy has a “mind-body problem” of a sort that did not exist before the mechanistic revolution, and why all materialist attempts to “explain” the mind are really disguised versions of eliminative materialism. The tiresome canard that “everything else has already been explained in materialistic terms” is thus a gigantic shell game, pure sleight of hand, a complete fraud from start to finish. (This is a theme I first explored in my book Philosophy of Mind and develop at length in The Last Superstition.)

In any case, we have now a third brief argument for dualism, which can be summarized as follows: Given the materialist’s own (mechanistic-cum-quantificational) conception of matter, colors, odors, tastes and the like as we experience them do not exist in the material world itself; but these qualities do exist in our perceptual representations of the material world; therefore, there exist features of the world – namely these sensory qualities or “qualia” that characterize our perceptual experiences – that are not material or physical features.

Obviously this argument raises questions about how these immaterial features relate to the material ones – Are they basic or emergent? How can they causally interact with the material ones? Do they inhere in a physical or a non-physical substance? – but the fact that it raises them has no bearing on the cogency of the argument itself. My own view is that the standard (Cartesian) dualist answers to such questions are problematic precisely because they buy into the same mechanistic conception of matter to which materialists are beholden. The right approach is to challenge that conception of matter, and return to the Aristotelian-Scholastic picture it replaced. But whether I am right about this or not is also irrelevant to the argument just given, which does not assume any Aristotelian-Scholastic premises, but simply draws out the consequences of the very conception of matter to which materialists themselves are committed. Whatever the deficiencies of Cartesian dualism, they do not approach the sheer incoherence and cluelessness of contemporary materialism.

The interaction problem

Aristotle and the Scholastic tradition influenced by him famously held that to understand a thing required knowing each of its four causes: its material cause, the stuff out of which it is made; its formal cause, the specific form or essence that stuff has taken on, and which makes it the kind of thing it is; its efficient cause, that which brought it into existence; and its final cause, the end or purpose toward which it is directed. Modern thought is largely defined by its rejection of two of Aristotle's four causes. For the moderns, there are no such things as substantial forms or fixed essences, and there are no ends or purposes in nature. There are just brute material elements related by purposeless, meaningless, mechanical chains of cause and effect.

As I have emphasized in my series of posts on dualism, this “mechanical” conception of nature, insofar as it stripped matter of anything smacking of either goal-directedness or sensible qualities as common sense understands them, and relocated these features into the mind, more or less automatically entailed a Cartesian form of dualism on which intentionality and qualia are immaterial as a matter of conceptual necessity. But it also automatically entailed that this form of dualism would suffer from the notorious “interaction problem.”

For the moderns, all causation gets reduced to what the Aristotelians called efficient causation; that is to say, for A to have a causal influence on B is for A either to bring B into being or at least in some way to bring into existence some modification of B. Final causality is ruled out; hence there is no place in modern thought for the idea that B might play an explanatory role relative to A insofar as generating B is the end or goal toward which A is directed. Formal causality is also ruled out; there is no question for the moderns of a material object’s being (partially) explained by reference to the substantial form it instantiates. We are supposed instead to make reference only to patterns of efficient causal relations holding between basic material elements (atoms, or corpuscles, or quarks, or whatever).

Thus, if the mind considered as immaterial is to have any explanatory role with respect to bodily behavior, this can only be by way of some pattern of efficient causal relations – to put it crudely, in terms of a Cartesian immaterial substance (or perhaps various immaterial properties) “banging” into the material substance (or material properties) of the brain like the proverbial billiard ball. How exactly this is supposed to work is notoriously difficult to explain. We’ve got two independently existing objects (or two independently existing sets of properties) somehow interacting the way physical particles or billiard balls do, or perhaps the way waves or fields of force do – except that one of these objects (or sets of properties) is utterly devoid of any of the material features that make it possible for something to count as a particle, billiard ball, wave, or field of force. Add to this considerations like the conservation of energy and interaction between the material and immaterial realms comes to seem ruled out in principle by our current understanding of the way the material world works.

But from an Aristotelian-Scholastic point of view, this whole picture of the mind-body relationship is hopelessly wrongheaded from start to finish. It is wrong to think of the soul (of which the intellect is for Aristotelians but a part, not the whole) and the body as independent objects in the first place. The soul is rather a form that informs the matter of the body and the body is the matter which is informed. As with the form and matter of a stone, tree, or earthworm, what we have here are not two substances interacting via efficient causation, but rather two metaphysical components of one substance related by formal causation. As the form of the stone is to the matter making up the stone, the form of the tree to the matter making up the tree, and the form of the earthworm to the matter that makes up the earthworm, so too is the human soul to the human body. There is in principle no such thing as the matter of a stone, tree, or earthworm apart from the form of a stone, tree, or earthworm respectively, and no such thing as the form of any of these things existing apart from their matter. The form and matter don’t “interact” as if they were two distinct objects; rather, the form constitutes the matter as the (one) kind of object it is in the first place.

Similarly, there is in principle no such thing as the matter of a living human body without a human soul and there is in principle no such thing as a human soul which is not the soul of some body. (This does not entail that the soul cannot survive the death of the body, only that it could not have existed in the first place unless it was united to some body; but this is a topic that can be bracketed off for present purposes.) The soul doesn’t “interact” with the body considered as an independently existing object, but rather constitutes the matter of the human body as a human body in the first place, as its formal (as opposed to efficient) cause.

As I move my fingers across the keyboard, then, what is occurring is not the transfer of energy (or whatever) from some Cartesian immaterial substance to a material one (my brain), which sets up a series of neural events that are from that point on “on their own” as it were, with no further action required of the soul. There is just one substance, namely me, though a substance the understanding of which requires taking note of each of its formal-, material-, final- and efficient-causal aspects. To be sure, my action counts as writing a blog post rather than (say) undergoing a muscular spasm in part because of the specific pattern of neural events, muscular contractions, and so forth underlying it. But only in part. Yet that does not mean that there is an entirely separate set of events occurring in a separate substance that somehow influences, from outside as it were, the goings on in the body. Rather, the neuromuscular processes are by themselves only the material-cum-efficient causal aspect of a single event of which my thoughts and intentions are the formal-cum-final causal aspect. There is simply no way fully and accurately to describe the one event in question without making reference to each of these aspects. Just as there is no such thing as the matter of a stone or tree apart from the form of a stone or tree, there is no such thing as the “physical” side of my action apart from the “mental” side. To make reference to the “physical” side alone would simply be to leave out half of the story, and indeed the most important half, just as describing the word “cat” in a way that makes reference to the shapes of the letters, the chemicals in the ink in which it is written, and so forth, while never saying anything about the meaning of the word, would leave out the most crucial part of that story.

As psychologist Jerome Kagan emphasizes in his recent book An Argument for Mind (my review of which can be found here) the trouble with trying to pick out some particular pattern of neural or other physiological events and identify some mental event with it (or in any other way attempt entirely to explain the mental in terms of the physiological) is that the same physiological pattern can underlie different mental events and the same mental event can be associated with different physiological patterns. This is a problem well-known to students of the history of the mind-brain identity theory (cf. Davidson’s anomalous monism), though it seems to me that many philosophers do not appreciate just how deep the problem goes, and how thoroughly devastating it is to materialism. As writers like James F. Ross have argued, at least some of our mental states are determinate in a way that no material process or set of processes can be even in principle, so that the hope of making mental states out to be identical with or supervenient upon physical states is an illusion. Without formal and final causes, it is inevitable that the project of assigning some specific, determinate mental content to this or that material substrate will come to grief. (Thus does the interaction problem arise in a new form even for materialists themselves, under the guise of the “mental causation problem.”)

Hence there can, on an Aristotelian-Scholastic view, be no question of some uniquely identifiable set of physiological events with which an independently identifiable set of mental events needs somehow to be correlated in efficient causal terms. There is just the one event of writing the blog post, of which the formal, material, efficient, and final causal components are irreducible aspects. The question of "interaction," in the relevant sense, simply cannot even get off the ground. As is so often the case with objections raised against modern defenses of traditional philosophical views (such as theism and natural law ethics), the interaction problem facing Cartesian forms of dualism arises precisely because these forms of dualism are modern, precisely because they take on board certain modern (especially mechanistic and/or nominalistic) assumptions which they (like theists and natural law theorists) ought instead to repudiate.

I have said much more about all of this in Philosophy of Mind and (especially) The Last Superstition, and I will say more about some of these issues in further posts to come in my series on brief arguments for dualism. The point for now is just to highlight that what we have here is yet another respect (among a great many others that I describe in detail in TLS) in which the early modern philosophers’ transition away from Aristotelianism to a mechanical understanding of nature constituted not an advance but a regression, a willful forgetting of crucial distinctions and categories the drawing and elucidation of which had been one of the great achievements of Scholasticism, and a conceptual impoverishment that inevitably created problems rather than solved them. The interaction problem was by no means the least, or last, of these problems.

Was Aquinas a materialist?

Denys Turner’s recent book Thomas Aquinas: A Portrait is beautifully written and consistently thought-provoking.  It is also a little mischievous, in a good-natured way.  A main theme of the book is what Turner characterizes as Aquinas’s “materialism.”  Turner is aware that Aquinas was not a materialist in the modern sense.  And as I have emphasized many times (such as at the beginning of the chapter on Aquinas’s philosophical psychology in Aquinas), you cannot understand Aquinas’s position unless you understand how badly suited the standard jargon in contemporary philosophy of mind is to describe that position.  Turner’s reference to Aquinas’s “materialism” is intended to emphasize the respects in which Aquinas’s position is deeply at odds with what many think of as essential to a “dualist” conception of human nature.  And he is right to emphasize that.  All the same, as I have argued before, if we are going to use modern terminology to characterize Aquinas’s view -- and in particular, if we want to make it clear where Aquinas stood on the issue that contemporary dualists and materialists themselves think is most crucially at stake in the debate between dualism and materialism -- then “dualist” is a more apt label than “materialist.”

Chomsky on the mind-body problem

I am, to say the very least, not a fan of Noam Chomsky’s writings on politics and foreign policy. But his straightforwardly philosophical work is always interesting and important even when one disagrees with it. A case in point is his view of the traditional mind-body problem. The usual assumption is that we have a clear understanding of what matter is, and that the difficulty has to do with explaining how thoughts, sensations, and other mental phenomena relate to material processes in the nervous system. Are the former identical to or supervenient upon the latter? Various anti-materialist arguments purport to show that they cannot be either, which seems to entail some form of dualism. But in that case we face the interaction problem. In any event, the “body” side of the mind-body problem is usually taken to be unproblematic; it is mind that raises the puzzles, or so it is thought.

Chomsky rejects this assumption. In his view, “body” is as problematic as mind; so much so that we do not even have a clear idea of what the mind-body problem is. As he writes in Language and Problems of Knowledge: The Managua Lectures:

The mind-body problem can be posed sensibly only insofar as we have a definite conception of body. If we have no such definite and fixed conception, we cannot ask whether some phenomena fall beyond its range. The Cartesians offered a fairly definite conception of body in terms of their contact mechanics, which in many respects reflects commonsense understanding. Therefore they could sensibly formulate the mind-body problem… (p. 142)

[However] the Cartesian concept of body was refuted by seventeenth-century physics, particularly in the work of Isaac Newton, which laid the foundations for modern science. Newton demonstrated that the motions of the heavenly bodies could not be explained by the principles of Descartes’s contact mechanics, so that the Cartesian concept of body must be abandoned. (p. 143)

In other words, when we think of causation in the natural world as Descartes did – that is, as involving literal contact between two extended substances – then the way in which a thought or a sensation relate to a material object becomes mysterious. Certainly it cannot be right to think of a thought or sensation as making literal physical contact with the surface of the brain, or in any other way communicating motion in a “push-pull” way. But when we give up this crude model of causation, as Newton did, the source of the mystery disappears. At the same time, no systematic positive account of what matter as such is has ever really been put forward to replace Descartes’ conception. Hence, Chomsky continues:

There is no longer any definite conception of body. Rather, the material world is whatever we discover it to be, with whatever properties it must be assumed to have for the purposes of explanatory theory. Any intelligible theory that offers genuine explanations and that can be assimilated to the core notions of physics becomes part of the theory of the material world, part of our account of body. If we have such a theory in some domain, we seek to assimilate it to the core notions of physics, perhaps modifying these notions as we carry out this enterprise. (p. 144)

That is to say, we have in Chomsky’s view various worked-out, successful theories of different parts of the natural world, and we try to integrate these by assimilating them to “the core notions of physics,” but may end up altering those core notions if we need to in order to make the assimilation work. As a result, as Chomsky once put it to John Searle, “as soon as we come to understand anything, we call it ‘physical’” (quoted by Searle in The Rediscovery of the Mind, p. 25). But we have no conception of what is “physical” or “material” prior to and independently of this enterprise. And since the enterprise is not complete, “physical” and “material” have no fixed and determinate content; we simply apply them to whatever it is we happen at the moment to think we know how assimilate into the body of existing scientific theory. As a consequence:

The mind-body problem can therefore not even be formulated. The problem cannot be solved, because there is no clear way to state it. Unless someone proposes a definite concept of body, we cannot ask whether some phenomena exceed its bounds. (Language and Problems of Knowledge, p. 145)

Hence, while Chomsky is no dualist, neither does he embrace the standard alternatives: “There seems to be no coherent doctrine of materialism and metaphysical naturalism, no issue of eliminativism, no mind-body problem” (New Horizons in the Study of Language and Mind, p. 91). In short, if the problem has no clear content, neither do any of the solutions to it. Chomsky’s preferred approach, it seems, is just to carry on the task of developing and evaluating theories of various aspects of the mind and integrating them as one can into the existing body of scientific knowledge, letting the chips fall where they may vis-à-vis the definition of “physical” or “material.”

What should we make of this? Chomsky is, I think, absolutely right to emphasize that the concept of matter is no less problematic than that of mind, and that this entails that “materialism” and “physicalism” are far less determinate in content than their adherents typically suppose. (This is something Bertrand Russell also emphasized, as do later philosophers of mind influenced by him, such as Grover Maxwell, Michael Lockwood, Galen Strawson, and David Chalmers.) At the same time, I think it is clear that the concept of the “physical” or the “material” is not in fact as elastic as Chomsky’s remarks might imply, either in the thinking of most scientists or in that of philosophical naturalists.

It is true that the positive content of the notion is fairly indeterminate, subject to fluctuation with every change in the physical sciences. But there is a core of negative content that is more or less fixed. That is to say, whatever matter turns out to be, there are certain features that modern philosophers, and scientists in their philosophical moments, tend to refuse ever to attribute to it.

For at least some of them, this would seem to include sensory qualities like color, odor, taste, sound, and the like as common sense understands them. For the mechanistic revolution Chomsky alludes to was not merely, and indeed not even essentially, committed to the idea that material causation involves literal contact. It was also and more lastingly committed to some variant or other of a “primary/secondary” quality distinction on which there is nothing in the material world that “resembles” our “ideas” of the sensory qualities mentioned (as Locke would put it). If we want to redefine the “red” of a fire engine in terms of how its surface reflects photons at certain wavelengths, we can say that the fire engine is red. But if by “red” we mean the way red “looks” to us when we perceive it, then nothing like that exists in the fire engine, which is (if we think of color in these commonsense terms) intrinsically “colorless.” And so on for sounds, tastes, and all the rest. Color, odor, taste, sound, and the like – again, as common sense understands them (rather than as redefined for purposes of physics) – are reinterpreted by mechanism as projections of the mind, existing only in consciousness. This is the origin of the “qualia problem,” and the puzzle now becomes how to relate these “qualia” or “phenomenal properties” to the intrinsically colorless, odorless, tasteless particles that make up the brain just as much as they do external material objects.

Now if one insists on denying these sensory qualities to matter, then it seems clear that we do have a clear enough conception of “body” to generate a mind-body problem. More than that, we have a conception that clearly implies that the mind (in which alone these qualities exist) cannot be something material or bodily – that, at any rate, is the lesson drawn by early modern thinkers like Cudworth and Malebranche, and by contemporary writers like Richard Swinburne, who take the “mechanistic” conception of matter itself to entail dualism. (I have discussed this issue before in several places, e.g. here, here, and in The Last Superstition.)

A naturalist could, however, decide to reincorporate the sensory qualities into the material world by conceiving of them as the intrinsic properties of matter, which “flesh out” the abstract mathematical structure described by physics. And this is precisely the move made by the writers influenced by Russell whom I mentioned above – Maxwell, Lockwood, Strawson, and Chalmers. To be sure, the resulting position is hardly “materialist” or “physicalist” as those terms are usually understood; some of these writers describe it instead as neutral monist, or panpsychist, or even as a variety of dualism. But they also tend to regard it as nevertheless consistent with a kind of naturalism, even if what is allowed to count as “natural” is thereby expanded considerably. (An exchange between Strawson and Chomsky can be found in Louise Antony and Norbert Hornstein, eds., Chomsky and His Critics.)

There is, however, another, more fundamental and indeed absolutely “non-negotiable” component of the mechanistic picture of the world inherited from the early modern philosophers, one well-known to regular readers of this blog: the rejection of Aristotelian formal and final causes. As I have argued in many places (such as in this recent post, as well as in The Last Superstition and Aquinas), this is the surviving and definitive element of the mechanistic revolution, and the one which naturalists seem to take, either explicitly or implicitly, to be crucial to their position. Whatever else the physical world may turn out to be like, and whatever alterations might be made to scientific practice, the mechanist, and the naturalist, are committed to the view that there is no such thing as goal-directedness or teleology intrinsic to the natural world, and that proper scientific procedure ought never to posit such immanent teleology. (See the quotes in the post just linked to for examples of philosophers who endorse this conception of science.)

If this is correct, then we once again have a conception of matter, albeit a negative one, which is determinate enough to generate a mind-body problem. If nothing in the material world inherently points beyond itself as to an end or final cause, then it is hard to see how that aspect of the mind philosophers call intentionality – the way that a thought “points to,” is “about,” or is “directed at” something beyond itself (such as the way your thought about the Eiffel tower is “about” or “directed at” the Eiffel tower) – can possibly be given a “naturalistic” explanation. As I have argued in several places (e.g. here) a dualism of intentional phenomena and material phenomena seems unavoidable given a mechanistic conception of nature, even if the Russellian naturalist can avoid a dualism of qualitative phenomena and material phenomena by expanding his conception of the “natural” (though even that is not a sure thing).

As Jerry Fodor puts it in Psychosemantics: The Problem of Meaning in the Philosophy of Mind:

I suppose that sooner or later the physicists will complete the catalog they’ve been compiling of the ultimate and irreducible properties of things. When they do, the likes of spin, charm, and charge will perhaps appear on their list. But aboutness surely won’t; intentionality simply doesn’t go that deep. It’s hard to see, in face of this consideration, how one can be a Realist about intentionality without also being, to some extent or other, a Reductionist. If the semantic and the intentional are real properties of things, it must be in virtue of their identity with (or maybe of their supervenience on?) properties that are themselves neither intentional nor semantic. If aboutness is real, it must be really something else. (p. 97)

Of course, Fodor’s “Reductionism” is not really the only option. One could combine Realism about intentionality with dualism instead; or with idealism; or with Aristotelian hylemorphism. But the last of these positions would indeed be ruled out if one agrees with Fodor about what the physicists’ ultimate catalog must look like, and the other two options would certainly be incompatible with at least most naturalists’ understanding of “naturalism.” In any event, the passage illustrates the point that contemporary philosophers do have a determinate enough conception of matter (albeit a negative one) to generate a mind-body problem: Fodor’s point is that given the conception of the physical to which he and like-minded philosophers are committed, intentionality becomes philosophically problematic. The passage illustrates also that the naturalist seems bound at the end of the day to deny the existence of intentionality given his conception of matter. For to say that “if aboutness is real, it must be really something else” is just a cute way of saying that aboutness is not real, and must be replaced in our ontology by some physicalistically “respectable” ersatz. As Searle has complained (e.g. in the book cited above), materialist “reductions” of this or that mental phenomenon never really succeed in “reducing” it at all, but either change the subject or implicitly deny the existence of the phenomenon. Reductionist versions of materialism are really just disguised forms of eliminative materialism.

That is a big topic, but suffice it for now to emphasize two points. First, while Chomsky is right to say that modern philosophers’ conception of “matter” or “the physical” is far less determinate than they often suppose, it is in fact determinate enough to generate a real mind-body problem. Second, the mechanistic assumptions underlying this determination of their conception of matter are, contrary to what they (and Chomsky himself, I imagine) typically suppose, not “scientific” at all, but purely philosophical – and (as my regular readers know) in my view deeply mistaken.

Scientism roundup

In several recent posts we have dealt at least indirectly with scientism, the view that the only real knowledge is scientific knowledge.  Scientism is an illusion, a bizarre fantasy that makes of science something it can never be.  Seemingly the paradigm of rationality, it is in fact incoherent, incapable in principle of being defended in a way consistent with its own epistemological scruples.  It should go without saying that this in no way entails any criticism of science itself.  For a man to acknowledge that there are many beautiful women in the world does not entail that he doesn’t think his own wife or girlfriend is beautiful.  Similarly, to say that there are entirely rational and objective sources of knowledge other than science does not commit one to denying that science is a source of knowledge.  Those who cannot see this are doubly deluded – like a vain and paranoid wife or girlfriend who thinks all women are far less attractive than she is and regards any suggestion to the contrary as a denial of her own beauty.  Worse, like an already beautiful woman whose vanity leads her to destroy her beauty in the attempt to enhance it through plastic surgery, scientism threatens to distort and corrupt science precisely by exaggerating its significance.

Gelernter on computationalism

People have asked me to comment on David Gelernter’s essay on minds and computers in the January issue of Commentary.  It’s written with Gelernter’s characteristic brio and clarity, and naturally I agree with the overall thrust of it.  But it seems to me that Gelernter does not quite get to the heart of the problem with the computer model of the mind.  What he identifies, I would argue, are rather symptoms of the deeper problems.  Those deeper problems are three, and longtime readers of this blog will recognize them.  The first two have more to do with the computationalist’s notion of matter than with his conception of mind.

Conceiving and hallucinating

The “conceivability argument” for dualism holds that (1) it is conceivable that I might exist apart from by body, and therefore that (2) it is metaphysically possible for me to exist apart from my body, so that (3) I am not identical to my body. I put forward a detailed and sympathetic exposition of this argument in chapter 2 of Philosophy of Mind – for it is more interesting and defensible than some philosophers give it credit for – but I do not in fact endorse it. It is essentially a variation on Descartes’ “clear and distinct perception” argument for dualism, and as I’ve argued elsewhere, what’s true in that argument isn’t new and what’s new isn’t true. (As an Aristotelico-Thomist I reject the rationalist assumptions inherent in Descartes’ version, and the Kripke-style modal assumptions inherent in modern versions. But demonstrating the mind’s immateriality does not require committing oneself to these assumptions.)

But as I say, the argument is more defensible than it is often given credit for. Take the thought experiment I discussed in Philosophy of Mind, W. D. Hart’s “seeing without a body” example. (Hart develops this example in his book The Engines of the Soul and in his article “Dualism” in Samuel Guttenplan, ed., A Companion to the Philosophy of Mind. Follow the links and you can read the relevant sections online via Google books.) Hart asks you to imagine that you wake up one morning, look in the bathroom mirror, and see staring back at you two empty eye sockets where your eyeballs used to be. This is no doubt physically impossible, but it does seem that we can at least conceive of having such an experience. There is no apparent contradiction or incoherence in the idea. Seeing without eyeballs is thus arguably metaphysically possible even if it is not physically possible.

Hart then asks us to extend the thought experiment in various ways. For example (and as I suggested extending it in the book) you might imagine that instead of seeing two empty eye sockets staring back at you, what you see in the mirror is the stump of your neck where your head used to be – a headless body, arms raised in horror. Seeing without a head, and thus without a brain, seems perfectly conceivable, then, and therefore (by the reasoning of the conceivability argument) at least metaphysically possible even if not physically possible. And if that is conceivable, so too is it conceivable to have the experience of seeing without arms, legs, torso, or any body at all; in which case (the argument claims) it is metaphysically possible to see without a body. But since seeing is a kind of mental state, it is therefore metaphysically possible to have a mind without a body.

Now, to evaluate the conceivability argument, we have to determine (a) whether what seems to be conceivable in this case really is conceivable, (b) whether conceivability really does entail metaphysical possibility, and (c) whether the metaphysical possibility of A existing without B really does entail that A and B are non-identical. I commend Hart’s discussion of these various issues (and also my discussion in Philosophy of Mind) to the interested reader. What I want to focus on here is just (a), and in particular on one possible challenge to (a).

A friend of mine sometimes reads this blog at work. (“I’m that bored,” he explains.) He’s been reading Philosophy of Mind, and when I saw him the other day he asked vis-à-vis the Hart example: “What does that prove? Isn’t it just obvious that I would be hallucinating?” That’s a fair question. We might put the objection this way: For the conceivability argument to work, we have to be able to show that (among other things) it really is conceivable to see without a body. But Hart’s example shows at most only that it is conceivable that we might have an experience that seems like the experience of seeing without a body. And that’s not good enough, because such an experience might be hallucinatory. “Seems like” does not entail “really is.” Therefore, “We can conceive of it seeming like such-and-such is the case” does not entail “We can conceive of such-and-such really being the case.”

But I think the objection fails. The reason is that hallucination seems parasitic on veridical experience in a way that ensures that if we can conceive of hallucinating something, it follows that we can conceive of really experiencing it. Consider that it isn’t just impossible to conceive of seeing a round square. It is also impossible to conceive of hallucinating a round square. And this is so, surely, precisely because it is impossible to conceive of seeing one. Hallucinating (or visually hallucinating, anyway) is just a kind of defective seeing. So, what’s impossible for seeing in general is impossible for hallucinations in particular. But then, if it were impossible for us to see without a body, it would also be impossible for us to hallucinate seeing without a body. So, since the Hart example at least shows (by the objector’s own admission) that the latter is possible, that suffices to show that the former is possible as well.

Or so it seems to me. The conceivability argument may or may not fail on other grounds, but I think that at least to this extent it is on solid ground.

Warby on Philosophy of Mind

Over at the online edition of Australia's Quadrant magazine, Michael Warby kindly reviews my book Philosophy of Mind. As Warby notes, the book is now out in a revised edition. (The first edition has the subtitle "A Short Introduction" and a surrealist cover illustration. The new edition, pictured at left, has a "brain in a vat" cover with the new subtitle "A Beginner's Guide." The only difference in content is the addition of an eight-page Postscript to the new edition.)

You can find a sample chapter here. Like the book in general (which first appeared in 2005), it is perhaps a tad too Cartesian and "representationalist" in spirit. Were I writing it today, I would make it more thoroughly Aristotelian-Thomist. (The philosophy of mind related portions of The Last Superstition reflect my transition toward a more consistent Thomism.) Still, Cartesianism is better than materialism, to say the very least.

Anyway, for interested readers, here is the complete table of contents:

Preface and acknowledgments

1. Perception

Dreams, demons, and brains in vats
Indirect realism
Skepticism
Appearance and reality, mind and matter
Further reading

2. Dualism

Minds and brains, apples and oranges
The indivisibility argument
The conceivability argument
The interaction problem
Further reading

3. Materialism

Tables, chairs, rocks, and trees
Reduction and supervenience
Cause and effect
Behaviorism
The identity theory
Functionalism
The burden of proof
Further reading

4. Qualia

The inverted spectrum
The “Chinese nation” argument
The zombie argument
The knowledge argument
Subjectivity
Property dualism
Further reading

5. Consciousness

Eliminativism
Representationalism and Higher-Order Theories
Russellian identity theory and neutral monism
Troubles with Russellianism
A more consistent Russellianism
Consciousness, intentionality, and subjectivity
The binding problem
Further reading

6. Thought

Reasons and causes
The computational/representational theory of thought
The argument from reason
The Chinese Room argument
The mind-dependence of computation
Thought and consciousness
Further reading

7. Intentionality

Naturalistic theories of meaning
1. Conceptual role theories
2. Causal theories
3. Biological theories
4. Instrumentalist theories
Eliminativism again
The indeterminacy of the physical
1. Representations
2. Concepts
3. Formal reasoning
Materialism, meaning, and metaphysics
Further reading

8. Persons

Personal identity
Consequences of mechanism
Hylomorphism
Thomistic dualism
Philosophy of mind and the rest of philosophy
Further reading

Postscript (2006)

Glossary