Searle and property dualism

David Lewis once wrote that “philosophical theories are never refuted conclusively. (Or hardly ever, Gödel and Gettier may have done it.)” To this list should be added John R. Searle, who has in my estimation conclusively refuted the computationalist theory of mind – not so much with his famous “Chinese Room” argument, but with the less well-known but far more devastating arguments presented in his paper “Is the brain a digital computer?” and in chapter 9 of his brilliant book The Rediscovery of the Mind. When (not if, but when) the philosophers and psychologists of the future look back at the bizarre fad for characterizing the brain as a kind of computer and the mind as software, and ask “So what the hell was that all about?”, Searle will be remembered as the man who did more than any other philosopher to break the spell of this illusion.

Searle is also an effective critic of other materialist theories of the mind. But though he rejects all extant forms of materialism, Searle also famously denies being any kind of dualist. Still, his critics regularly insist that his views nevertheless entail dualism whether he realizes it or not, and that this suffices to show that they are mistaken. In short, Searle says: “My arguments are correct, and they do not entail dualism,” while his critics say: “Searle’s arguments do entail dualism, and therefore they are incorrect.” In my view both sides are partly right and partly wrong: Searle’s arguments are correct, and they do entail dualism.

As my longtime readers know, the version of dualism I think one ought to accept is Aristotelian-Thomistic hylemorphic dualism. As it happens, Searle’s views have been compared by some commentators to Aristotle’s (see e.g. Alan Code’s essay in Lepore and van Gulick’s John Searle and his Critics). But Searle rejects any such interpretation. (At a conference at which Searle and I were both presenters, I gave a paper the first part of which put forward a diagnosis and critique of naturalistic theories of the mind, and the second part of which proposed a return to hylemorphism as a remedy. Searle called the first part “brilliant” and the second part “crazy.” Coming from a man whose work I admire so much, that was good enough for me. The first part, incidentally, would go on to become “Hayek the cognitive scientist and philosopher of mind,” in The Cambridge Companion to Hayek. The second part was merely a sketch of ideas that I have developed in more detail elsewhere, most fully in The Last Superstition and in the forthcoming Aquinas.)

Indeed, when Searle has worked his positive views out more fully, the version of dualism they end up resembling most is property dualism. But Searle rejects this interpretation as well, arguing against it at length in his article “Why I am not a property dualist.” Victor Reppert kindly linked yesterday to a paper of mine, “Why Searle is a property dualist,” which replies to this article of Searle’s. Since Searle’s essay has just been reprinted in his new anthology Philosophy in a New Century, I thought I would post a link of my own to my reply, for what it is worth.

(Bonus link: Here is an interview Steven Postrel and I did with Searle for Reason magazine some years back. Among other things, it gives a good sense of Searle’s political views, which aren’t quite the sort you’d expect from a UC Berkeley professor.)

Against “neurobabble”

Every written token of the English word “soup” is made up of marks which look at least vaguely like “s,” “o,” “u,” and “p.”  Of course, it doesn’t follow that the word “soup” is identical to any collection of such marks, or that its properties supervene on the material properties of such marks, or that it can be explained entirely in terms of the material properties of such marks.  Everyone who considers the matter knows this.

To borrow an example from psychologist Jerome Kagan, “as a viewer slowly approaches Claude Monet's painting of the Seine at dawn there comes a moment when the scene dissolves into tiny patches of color.”  But it doesn’t follow that its status and qualities as a painting reduce to, supervene upon, or can be explained entirely in terms of the material properties of the color patches.  Everyone who considers the matter knows this too.

Somehow, though, when neuroscientists discover some neural correlate of this or that mental event or process, a certain kind of materialist concludes that the mind’s identity with, or supervenience upon, or reducibility to, or complete explanation in terms of neural processes is all but a done deal, and that the reservations of non-materialists are just so much intellectually dishonest bad faith.  In a recent online op-ed piece for The New York Times, and in an apt phrase, philosopher of mind Tyler Burge criticizes this tendency as “neurobabble,” which produces only “the illusion of understanding.”  For it is as fallacious as any parallel argument about words or paintings would be.

Churchland on dualism, Part II

Let’s continue our look at Paul Churchland’s critical discussion of dualism in his textbook Matter and Consciousness. I have noted that while Churchland neglects even to mention the most important arguments for dualism and devotes space to arguments that dualist philosophers themselves don’t actually put much stock in, he does at least discuss two arguments that many such philosophers do think important: the argument from introspection and the argument from irreducibility.

As Churchland summarizes the argument from introspection, it states that the thoughts, sensations, desires, and emotions we encounter in introspection are just plainly different from electrochemical activity in neural networks. As he summarizes the argument from irreducibility, it states that language, reasoning, the introspectible qualities of sensations, and the meaningful contents of our thoughts cannot plausibly be accounted for in materialist terms; for example, knowledge of the molecular structure of a rose and/or of the brain would not allow a physicist or chemist to predict what it would be like to experience the smell of a rose.

Churchland’s summary of these arguments is superficial. For example, it is clear from his gloss on the argument from irreducibility that he regards Frank Jackson’s famous “knowledge argument” as an important instance of it. Yet he does not actually state Jackson’s argument, thus denying the unwary reader an opportunity to appreciate its full power. (Churchland does briefly discuss Jackson’s argument later in the book, but only after having disposed of dualism and plumped for materialism, thus giving the misleading impression that the argument is merely a puzzle an already-established materialism must solve rather than an independent argument for dualism in its own right.)

Worse than this, though, are the responses he gives to the two arguments in question, which are presented as decisive but are in fact exceedingly feeble. The argument from introspection has no force, Churchland assures us, because introspection cannot be trusted in light of the fact that there are clear cases from the history of science showing that our natural powers of observation have misled us in other domains. What cases are these? “The red surface of an apple does not look like a matrix of molecules reflecting photons at certain critical wavelengths, but that is what it is,” Churchland says; “The sound of a flute does not sound like a sinusoidal compression wave train in the atmosphere, but that is what it is. [etc.]”

The problem with this response should be obvious, at least to someone with knowledge of the history of the mind-body problem and of modern philosophy generally. In particular, there is an obvious reason why the cases Churchland appeals to not only do not make the point he thinks they do, but in fact make the case for dualism even stronger. For the reason the identities in question – red with such-and-such a light wavelength, sound with a such-and-such a wave pattern, etc. – are plausible in the first place is that the early modern thinkers who inaugurated the “mechanical” conception of nature that informs modern science introduced a crucial distinction between features of the observable world that are observer-relative and those that are observer-independent – the famous primary quality/secondary quality distinction (spelled out in different ways by Galileo, Descartes, Locke, et al.). Colors, sounds, heat, cold, and the like as common sense understands them were relegated to the “observer-relative” side of the divide, and color, sound, heat, cold, etc. as objective, physical properties were, accordingly, redefined in terms of wave activity, the motions of particles, or some other “observer-independent” phenomena.

To see how this works in the case of one of Churchland’s examples, let’s distinguish between RED (in caps) and red (in italics) as follows:

RED: the qualitative character of the color sensations had by a normal observer when he looks at fire engines, “Stop” signs, Superman’s cape, etc. (which is different from the qualitative character of the sensations had by e.g. a color blind observer)

red: whatever physical property it is in fire engines, “Stop” signs, Superman’s cape, etc. that causes normal observers to have RED sensations

Now what seems to common sense to be very different from “a matrix of molecules reflecting photons at certain critical wavelengths” is RED. And sure enough, what science has shown to be identical to “a matrix of molecules reflecting photons at certain critical wavelengths” is only red, not RED. Indeed, part of the reason for distinguishing red and RED is precisely that RED seems clearly not to be identical to something like “a matrix of molecules reflecting photons at certain critical wavelengths,” since the “matrices of molecules” etc. are what they are regardless of who is looking at them while qualitative character is observer-relative.

Part of the problem with Churchland’s response to the argument from introspection, then, is that it commits a fallacy of equivocation: The sense of “red” in which “Red seems different from any property of a matrix of molecules etc.” (i.e. RED) is different from the sense of “red” in which “Science has shown that red really is just a property of a matrix of molecules etc.” (i.e. red). A similar fallacy is committed when he appeals instead to sounds or any other sensory qualities. Thus his examples do not show that our powers of observation have misled us in other domains, and thus should not be trusted in the case of introspection.

That’s one problem with his response. Another is that when we understand what is really going on in the history-of-science examples Churchland appeals to, we can see that they actually strengthen the case for dualism rather than undermine it. For if colors, sounds, heat, cold, etc. as common sense understands them – that is, in terms of their qualitative, phenomenal character – exist only in the mind of the observer and not in the physical world (which is comprised of nothing more than colorless, odorless, soundless, tasteless particles in motion, or whatever), then it seems clear that they cannot exist in the brain, or in any other physical object or system of physical objects, either. Hence they must be immaterial. As I have noted before, that was exactly the conclusion explicitly drawn by early modern thinkers like Cudworth and Malebranche – and at least implicitly by Descartes, Locke, and the other early modern advocates of the “mechanical philosophy” who also happened to be dualists – and by several philosophers since. Their view was that dualism, far from being a pre-scientific holdover destined to be abandon once we have sufficient knowledge of the brain, in fact follows from the very mechanistic conception of matter taken for granted in modern science. The basic problem was one of the themes of Thomas Nagel’s celebrated 1974 article “What is it like to be a bat?” (though Nagel is less committal there about precisely what philosophical conclusion we ought to draw from the problem). It was explicitly appealed to in defense of dualism in Richard Swinburne’s 1986 book The Evolution of the Soul.

Now Churchland or some other materialist might think there is a way to carve up the conceptual territory that doesn’t have such an implication. Fine and dandy, let’s hear it and evaluate it. But he oughtn’t to pretend that the “reductions” in question clearly favor materialism when in fact, historically, they were taken to favor the opposite view! And, especially, he oughtn’t to convey this false impression when purporting to offer an evenhanded presentation of the case for dualism.

Churchland’s treatment of the argument from irreducibility is equally bad. As evidence that our powers of reasoning can in fact be accounted for in materialistic terms, he appeals to the existence of electronic calculators. As evidence that language can be similarly accounted for, he appeals to the existence of “computer languages.” He fails even to mention the most glaringly obvious reply to such “explanations” – that they involve nothing more than a couple of bad puns, since so-called calculators don’t literally “calculate” and computers don’t literally possess “language.” Rather, both electronic calculators and computers generally are inherently devoid of any intentionality or powers of reasoning whatsoever, and have simply been designed by human beings – who do have genuine powers of reasoning and language – to carry out certain operations that aid us in our exercises in calculation and the like by simulating certain mental processes. To “explain” mental phenomena in terms of what computers do is thus precisely to get things back-asswards, since what computers do cannot be accounted for apart from the human minds which assign to their states and operations whatever meanings they have.

Again, the point isn’t that Churchland might not have a way to respond to such arguments. The point is that he pretends that the claims he makes easily and uncontroversially rebut the argument from irreducibility when in fact his claims are extremely controversial even among non-dualists. (John Searle and Hubert Dreyfus are only the two most prominent non-dualist philosophers to have criticized the suggestion that mental processes can be explained in terms of “computational” ones.) The hapless beginning student coming away from Churchland’s discussion would have no idea that his “Gee whiz, look what computers can do!” shtick is, by itself anyway, philosophically about as serious as “proving” that time travel is theoretically possible based only on what one saw once in a Star Trek episode.

Churchland also suggests that whatever explanatory difficulties materialism has are at least equally matched by any dualist attempt to explain mental phenomena in terms of “nonphysical mind-stuff.” Here again Churchland proves only that he doesn’t understand what the main arguments for dualism actually say. As I noted in my first post in this series, those arguments are not quasi-scientific “explanatory hypotheses” in the first place, but rather attempts at metaphysical demonstration. They do not “postulate” “mind-stuff” (whatever that is) any more than mathematicians “postulate” the existence of the number 48 as the “best explanation” of why 47 and 49 do not fall right next to each other in the series of natural numbers. If the arguments fail, they do not fail for the sorts of reasons that explanatory hypotheses fail (considerations of parsimony, lack of fit with existing empirical theory, etc.), any more than an attempted mathematical proof, when it fails, can fail for such reasons.

But that brings us to Churchland’s positive arguments against dualism, which we’ll look at in a third post.

Churchland on dualism, Part IV

Daniel Stoljar’s remarks on dualism, which I criticized in an earlier post, bring to mind some similar remarks made by Paul Churchland in response to Frank Jackson’s famous “knowledge argument” against physicalism. You’ll recall that Stoljar claimed that objections to a physicalist account of intentionality would apply no less to a dualist account. Churchland makes the same claim with respect to qualia – the introspectible features of a conscious experience, in virtue of which there is “something it is like” to have that experience. (Stock examples of qualia would be the way pain feels, the way red looks, or the way coffee tastes and smells.)

Jackson’s argument goes roughly like this. Imagine that Mary, a master neuroscientist of the future, has lived her entire life in a black and white room, never having had any experience of colors. But she knows everything there is to know about the physical facts concerning the physics and physiology of color perception. Thus, though she’s never seen a red object herself, she knows exactly what happens in other people’s eyes and nervous systems when they see red, as well as all the relevant facts about light, surface reflectance properties of red objects, and so on. Eventually she leaves the room and sees a red object for the first time. Does she learn something new? Jackson says she clearly does – she learns what it’s like to see red. And that (so the argument goes) suffices to refute physicalism. For physicalism claims that to know all the physical facts about human beings is to know all the facts about them, period. But though Mary knew all the relevant physical facts about color perception prior to her release from the room, she didn’t know all the facts, because she learned something new upon her release. Hence there is more to human nature than is captured by a description of the physical facts. In particular, facts about qualia (such as the facts about what it’s like to see red) are additional facts, beyond the physical facts.

I will have more to say about the knowledge argument – and in particular about Jackson’s later change of heart about it – in a future post. For now let’s consider Churchland’s objection, which he first stated in his paper “Reduction, Qualia, and the Direct Introspection of Brain States” and repeated in his later paper “Knowing Qualia: A Reply to Jackson.” (Both papers are reprinted in Churchland’s book A Neurocomputational Perspective, which is the source of the quotes below.) In the course of making several other criticisms of Jackson, Churchland says that if the knowledge argument were sound, it would refute substance dualism for the same reasons it would refute materialism. For we need only run the argument by imagining instead that Mary is a master “ectoplasmologist” with knowledge of the “hidden constitution and nomic intricacies” of ectoplasm, and in particular of “everything there is to know about the ectoplasmic processes underlying vision” (“Reduction, Qualia, and the Direct Introspection of Brain States,” p. 63). Since Mary would learn something new upon leaving the room despite knowing everything there is to know about ectoplasm, this parallel argument “would ‘show’ that there are some aspects of consciousness that must forever escape the ectoplasmic story” (“Knowing Qualia,” p. 72, emphasis in the original).

But Churchland is just making the same mistake we saw Stoljar make. What philosophical dualist ever said anything about “ectoplasmic processes,” or about the “hidden constitution” or “nomic intricacies” of an immaterial substance? Even apart from the “ectoplasm” nonsense – which is, of course, just a rhetorical flourish intended to make dualism sound ridiculous before it is even given a hearing – Churchland’s description of dualism is a ludicrous caricature. He makes it sound as if the dualist were committed to the existence of an object which is just like a material object in having various parts arranged in a certain way so as to behave according to law-like regularities, only one made out of some ghostly kind of stuff rather than of matter. But that is precisely the opposite of what a Plato, an Aquinas, or a Descartes actually held. For them, as for philosophical dualists generally, the soul is necessarily something simple or non-composite, and thus without parts of either a material or a quasi-material sort. Hence it has no “hidden constitution” or “nomic intricacies” of the sort Churchland has in mind. It is not a kind of ghostly mechanism because it is not a “mechanism” at all. (True, Descartes was a mechanist, but only concerning the material world, not the mind.)

For the Cartesian dualist, who is Churchland’s immediate target, the essence of the soul is just to think, and thought is (on this view) essentially conscious. As Descartes says in a letter to Mersenne, “nothing can be in me, that is to say, in my mind, of which I am not conscious” (Descartes, Philosophical Letters, p. 90, emphasis in original), and as he writes in the replies to the Second Set of Objections, “thought is a word that covers everything that exists in us in such a way that we are immediately conscious of it” (Haldane and Ross, Philosophical Works of Descartes, vol. II, p. 52, emphasis in original). In the Fifth Set of Objections, Gassendi had complained that Descartes fails to provide an account of the “internal substance” of the mind, which would require something analogous to the “chemical investigation” by which we discover what unseen properties of wine determine its surface features (Cottingham, Stoothoff, and Murdoch, Philosophical Writings of Descartes, vol. II, p. 193). Descartes replied, in words that could have been directed at Churchland: “You want us, you say, to conduct ‘a kind of chemical investigation’ of the mind, as we would of wine. This is indeed worthy of you, O Flesh, and of all those who have only a very confused conception of everything, and so do not know the proper questions to ask about each thing” and (in response to another of Gassendi’s objections) that “your purpose was simply to show us what absurd and unjust quibbles can be thought up by those who are more anxious to attack a position than to understand it” (Ibid., pp. 248-49). For Descartes, your res cogitans isn’t something which, by virtue of some hidden internal constitution, generates your consciousness; your res cogitans just is your consciousness.

For that reason, there can be no “knowledge argument” against substance dualism parallel to Jackson’s argument against physicalism. If the Mary of Churchland’s alternate scenario does not know what it is like to experience red before leaving the room, then she just does not and cannot know everything there is to know about res cogitans, because experiencing red is nothing more than a mode of consciousness and (therefore) a mode of res cogitans. To know everything there is to know about a res cogitans would not involve knowing about its internal constitution, the causal relations holding between its parts, etc. (for it has none of these things) but would involve instead knowing every kind of conscious thought or experience it might have – including experiencing red. The “gap” between two kinds of fact that Jackson’s original argument points to does not have even a prima facie parallel in the substance dualist case. The physicalist has to acknowledge at least a conceptual difference between physical facts and facts about consciousness; the only question is whether there is also a metaphysical difference. But there is, according to the Cartesian dualist, not even a conceptual difference between facts about res cogitans and facts about consciousness. That’s Descartes’ whole point.

Whatever other objections the physicalist might raise against dualism, then, the tu quoque strategy employed by Churchland and many other contemporary materialists is simply incompetent. It rests on a fundamental misunderstanding of what the dualist means by an “immaterial substance.” Equally incompetent is any critique of dualism that treats it (as Churchland evidently does in “Knowing Qualia”) as a kind of quasi-scientific empirical theory – that is, as if it were “postulating” the existence of immaterial substance as the “best explanation” of mental phenomena among the various alternatives. As I noted in a previous post on Churchland, that is not at all what the most significant dualists in the history of philosophy were up to. Their arguments for dualism are intended instead as strict metaphysical demonstrations of the existence of the soul. One may or may not think the attempted demonstrations succeed, but one will not refute them unless one first understands what sort of argument they are intended to be. Dualists traditionally tend to regard metaphysical inquiry as an enterprise every bit as rational as, but distinct from and more fundamental than, empirical science. Committed as they often are to scientism, contemporary materialists would no doubt deny that there can be any such form of inquiry, but they cannot deploy this denial in an argument against dualism without begging the question.

Their unreflective scientism is no doubt one source of contemporary materialists’ systematic misunderstanding of dualism. Since they think all rational inquiry must be a kind of scientific inquiry, they tend to (mis)interpret the claims of dualists (as they often do the claims of theists) as if they were feeble exercises in empirical hypothesis formation. It seems to me that another source might be the enormous influence Gilbert Ryle’s book The Concept of Mind had on mid-twentieth century philosophy. For Ryle there characterized Descartes’ position, absurdly, as a “para-mechanical hypothesis” on which minds are “rather like machines but also considerably different from them,” being “spectral machines” that are “complex organized unit[s]” which run on “counterpart” principles to those of physical substances, “made of a different sort of stuff and with a different sort of structure” which might be thought of “not [as] bits of clockwork [but rather] just bits of not-clockwork” and where the “bits” are arranged into a “field of causes and effects” (pp. 18-20). It is as if Churchland’s generation of materialists got their “knowledge” of what dualists believe from reading Ryle, and the generations since have gotten their “knowledge” from reading people like Churchland.

In any event, the materialist who characterizes the soul in terms of “ectoplasm” is like the atheist who compares the God of classical theism to the “Flying Spaghetti Monster” or thinks that the cosmological argument starts with the premise that “Everything has a cause…” Not to put too fine a point on it, neither one knows what the hell he is talking about or has any business opening his mouth on the subjects in question.

The interaction problem, Part II

In an earlier post, I suggested that one of the advantages of hylemorphic dualism over Cartesian dualism is that its notion of formal causation allows it to sidestep the interaction problem. For if the soul is the form of the body, rather than a distinct substance in its own right, then there is no question of two substances having to “interact” in the order of efficient causes on the model of two billiard balls. There is rather just the one substance, a human being, having (as every other material substance has) two constituents, its form (or soul) and its matter (or body). The “interaction” between them is no more problematic than the “interaction” between the form of a tree and the matter that makes up the tree. For soul and body do not “interact” in the first place the way two distinct things do; they together constitute a single thing. My intention to raise my hand is not one event which has somehow to get into causal contact with another, physical event. It is rather the formal-cum-final cause of a single event of which the activity in my nervous system and arm is the efficient-cum-material cause. The solution to the “interaction problem” is to break out of the conceptual Procrustean bed of the mechanical picture of the world and return to a philosophy of nature informed by Aristotle’s four causes.

(Actually, saying that this “sidesteps” the interaction problem is misleading and anachronistic, since it conveys the false impression that hylemorphic dualism was motivated in part by a desire to solve the interaction problem. In fact there was no interaction problem until early modern philosophers like Descartes abandoned hylemorphism and redefined matter, mind, and causation in an explicitly anti-Aristotelian way. As I show in The Last Superstition, the “mind-body problem,” like the “traditional” philosophical problems of induction, personal identity, causation, and many others, is largely a consequence of the early moderns’ mechanistic revolution.)

Some modern dualists have suggested that the interaction problem is oversold in the first place. And they are right to complain that materialists fling it around much too glibly. To be sure, the interaction problem really is a problem for Cartesian dualism, but it is not (by itself, anyway) a refutation of it. Let’s briefly consider why – before going on to see why it is nevertheless a serious enough problem that any dualist is well-advised to consider opting for hylemorphic dualism over the Cartesian variety (especially given that, as I would argue, there is already ample independent reason to adopt hylemorphism as a general metaphysics).

One reason why the interaction problem does not strictly refute Cartesian dualism is that the Cartesian dualist could always simply deny that mind-body interaction is real in the first place, and opt for occasionalism, or parallelism, or epiphenomenalism. Of course, the extreme oddity of these views leads many critics of Cartesian dualism to regard recourse to them as little better than an admission of defeat, a desperate appeal to a deus ex machina. As Bill Vallicella notes (without necessarily endorsing the judgment) both Malebranche’s occasionalism and Leibniz’s pre-established harmony have been accused of deploying a deus ex machina strategy, especially since both literally appeal to God to resolve the question of the mind-body relationship.

But though the charge is common, it is unfair. Malebranche and Leibniz both had independent philosophical reasons for believing in God, and both also had independent reasons for denying that there could be causal interaction between created substances (any substances, not just mind and body). And given their respective specific understandings of the nature of substances, Malebranche had good reason to think that God continuously mediates between them, and Leibniz to think that God does not do so but instead established a universal harmony between them at creation. Hence, Malebranche quite naturally concluded that (for example) when you decide to have a beer your body moves towards the fridge, not because the decision causes the bodily movement, but because God, on noting that you have made that decision, causes the body so to move. And given his different conception of substance, Leibniz quite naturally concluded instead that the decision and the bodily movement in question were each simply the natural unfolding of what was pre-programmed into each substance at their creation. These views of the mind-body relationship were not developed simply to deal with the interaction problem, but flowed naturally from two sophisticated and independently defensible metaphysical positions.

Defensible, but still bizarre, rarely actually defended, and subject to various objections of their own. And most modern dualists would agree with materialists that it would be preferable to avoid occasionalism and pre-established harmony if one can manage it. Hence the greater popularity of epiphenomenalism, according to which mental events do not cause physical events but are rather merely the ineffectual byproduct of the flux of physical events. When you decide to have a beer, the decision itself (or at least the conscious awareness of it) is not what causes your body to walk over to the fridge. Rather, entirely unconscious physical events caused your body to do so, and in the process also caused the conscious experience of making the decision in question, which event itself had no causal efficacy at all.

Though not much less bizarre than occasionalism and pre-established harmony, epiphenomenalism at least has this advantage over them as a way for Cartesian dualists to deal with the mind-body problem: Materialists too seem led into it, so that they can’t plausibly use it as a stick with which to beat dualists. For materialist theories of mind have a notorious problem explaining the efficacy of mental content. If (as materialists tend to hold) it is only the physical properties of mental states which give them their power to cause other physical states, then their mental or intentional content seems epiphenomenal. For example, if we suppose, as a materialist might, that my decision to have a beer is identical with or at least supervenes upon some event in my nervous system, then if it is only the physiological properties of that event that enter into the explanation of how it caused my bodily movements, the fact that it involved a representation of beer, specifically, or indeed had any representational content at all, drops out as causally irrelevant.

So, if materialists as well as Cartesian dualists are faced with the possibility of having to swallow epiphenomenalism, the former cannot accuse the latter of having a special difficulty in accounting for mind-body interaction. Still, this is more a rhetorical victory for Cartesian dualism rather than a substantive one. For epiphenomenalism is notoriously unsatisfactory, and not just because it is odd to say that your decision to have a beer is not what caused you to go to the fridge. If our mental states can have no causal influence whatsoever on our bodies, it would seem to follow that we cannot even talk about them. Indeed, the epiphenomenalist himself could not even talk about his thoughts about epiphenomenalism. For those thoughts would be as inefficacious as any other mental state or event. When he says “Epiphenomenalism is true,” the fact that he thinks it is true has absolutely nothing to do with his saying so. This is bizarre at best and incoherent at worst. And though epiphenomenalists have tried to find various ways around the problem, it would be better not to have to deal with it in the first place.

So, a Cartesian dualist is well-advised not to deny that mind and body interact. And this brings us to the second reason why a Cartesian dualist has a right to complain that his critics’ appeal to the interaction problem is often too glib. As Bill Vallicella has pointed out in several past posts, whether a Cartesian dualist can account for mind-body interaction depends on what view of causation one is assuming. And there is at least one view of causation – a regularity theory – on which no interaction problem arises at all for Cartesian dualism. As Bill has suggested:

Suppose we say that:

Event-token e1 causes event-token e2 if and only if (i) e1 temporally precedes e2, and (ii) e1 and e2 are tokens of event-types E1 and E2 respectively such that every tokening of E1 is followed by a tokening of E2.

On this Hume-inspired theory (sans the contiguity condition), causation is just regular succession. If this is the correct theory of causation, then there is nothing problematic about mental events causing physical events, and vice versa.

About this, Bill is absolutely right. If such a regularity analysis is correct – and there are philosophers who would defend such an analysis on grounds independent of their position on the mind-body problem – then the interaction problem is solved. At the very least Cartesian dualists can plausibly hold that objections to their position based on the interaction problem are less conclusive than their critics often let on.

But the “if” in question is a very big one. Is such a regularity theory of causation really plausible in the first place, or at least plausible enough to show that Cartesian dualism really can account for mind-body interaction after all? I think not. One reason why is that apart from its use of the word “cause,” the proposed analysis is perfectly compatible in substance with occasionalism, parallelism, and epiphenomenalism. For on each of those views, it is perfectly possible to say that a mental event of type M is always followed by a physical event of type P, in which case, on Bill’s suggested regularity theory, M will count as the cause of P. But an “interactionist” theory which differs in substance not at all from occasionalism, parallelism, or epiphenomenalism – all of which deny interaction – is an “interactionist” theory in name only.

Another problem with the proposed regularity analysis is that it simply doesn’t capture what we mean by “cause.” As Hume himself recognized, the connection we take to hold between a cause and its effect is not just a regular one, but also a necessary one. We don’t just think A was in fact followed by B, but that in some sense it had to be followed by B. Of course, Hume thinks there is no objective source for this idea of necessity, that it has to be traced to a purely subjective expectation on our part. For he holds that there is nothing in our ideas either of a cause or of its effect that necessarily links them together. Objectively speaking, causes and effects are “loose and separate,” and any effect or none could in theory follow upon any cause.

This Humean result is what makes “regularity” theories of causation seem at all plausible. But what they really give us is not causation, but rather only some replacement for causation. (The same holds true, I would say, for counterfactual analyses of causation.) So, no appeal to such a theory really solves the interaction problem at all. Rather, it simply adds one mystery to another, saying, in effect: “Causation in general is already mysterious, so why shouldn’t mind-body interaction be?”

The thing is, the reason causation in general is mysterious is the same reason mind-body interaction in particular is: the mechanistic revolution that displaced the Aristotelian-Scholastic model of explanation, throwing out formal and final causes and trying to make do with bastardized versions of material and efficient causes. As I have noted in earlier posts and discuss at length in TLS, one of the main arguments the Aristotelian tradition gives for formal and final causes is that without them efficient causation becomes unintelligible. Unless there is something in the nature (or “substantial form”) of a thing by virtue of which it “points to” or is “directed at” the generation of a certain effect (as its final cause) then there is no way to account for why exactly it produces that effect as opposed to some radically different effect, or none at all. Hume was merely drawing out the inevitable consequences of the mechanistic revolution. (And even here Hume is, as always, overrated, since the skepticism vis-à-vis causation implicit in the rejection of formal and final causes was already foreshadowed in Ockham and the late medieval nominalist tradition.) The way to solve both the interaction problem and the problem of causation is, accordingly, the same: a return to the Aristotelian metaphysics early modern philosophy displaced.

Some brief arguments for dualism, Part II

Following Aristotle, the Scholastic tradition famously held that final causes – goal-directedness, purposiveness, natural ends – permeate the natural world. Contrary to a popular misconception, this does not mean that they thought that everything in the world has a purpose or function in the sense that biological organs have purposes or functions. Hence it is no good to accuse them of thinking, absurdly, that piles of dirt, asteroids, mountain ranges, and the like simply must play some role within the universe as a whole that is somehow analogous to the role hearts and kidneys play in the body. Functions like the kind bodily organs play constitute only one, relatively rare, kind of final causality. Nor did they think that final causality is generally associated with anything like consciousness. For an Aristotelian to say that a plant by virtue of its nature “wants” to grow is just a figure of speech. Literally speaking the plant does not, of course, want anything at all, since it is totally unconscious. It is only in us, and in certain other animals, that final causes are associated with conscious awareness.

What the Scholastics did have in mind is summed up in Aquinas’s dictum that “every agent acts for an end,” otherwise known as the “principle of finality.” By an “agent” he means that which brings about or causes some effect. And what he is saying is that when a certain cause generates a certain effect or range of effects in a law-like way (as we would say today) that is only because it naturally “points to“ or is “directed towards” that effect or range of effects as its proper end. For example, a match when struck will, unless prevented (e.g. by being water damaged), generate flame and heat – and flame and heat specifically rather than frost and cold, or the smell of lilacs, or no effect at all. It has an inherent causal power to bring about that effect specifically. What Aquinas and the other Scholastics argued is that unless we acknowledge the existence of such inherent powers, unless we recognize that whenever a certain efficient cause A generates its effect B that is only because the generation of B is the final cause or natural end of A, then we have no way of making intelligible why it is exactly that A generates B specifically rather than some other effect or no effect at all. The existence of final causes is, in this sense, a necessary condition for the existence of efficient causes – of, that is to say, causation as modern philosophers tend to understand it. This is one reason Aquinas held the final cause to be “the cause of causes.”

Now modern philosophy, and in particular modern philosophy’s conception of science, is defined more than anything else by its rejection of final causes. Indeed, as philosophers like William Hasker and David Hull have pointed out, at this point in the history of science, what remains of the “mechanistic” picture of the natural world which we have inherited from the early moderns is really nothing but this rejection. As I argue in The Last Superstition, there has never really been any serious philosophical case for this rejection; it was, and still is, more ideologically than intellectually motivated. Moreover, there are in my view (and, again, as I argue in TLS) overwhelming reasons to think it was a mistake. One of them is that, as Hume’s famous puzzles illustrate, causation has indeed become seriously problematic in modern philosophy in exactly the way Aquinas’s analysis would lead us to expect it to, given the abandonment of final causes.

The abandonment of final causes has also crucially contributed to the creation of the “mind-body problem,” something that did not exist, certainly not in anything like the form familiar to contemporary philosophers, prior to the moderns’ rejection of the Aristotelian-Scholastic metaphysical framework. For to insist that the material world is utterly devoid of final causes – devoid, that is to say, of anything that inherently “points to” or is “directed toward” anything beyond itself – is implicitly to deny that intentionality could possibly be material, for intentionality, of course, is just the mind’s capacity to point to or be directed towards something beyond itself, as it does in thought. (See my previous post in this series.) Hence to insist that the material world is devoid of any inherent final causes while at the same time acknowledging the existence of intentionality is implicitly to commit oneself to dualism. Indeed, this is surely one reason why Descartes, one of the fathers of the “mechanistic” revolution in science, was a dualist. Far from being a kind of pre-scientific holdover, dualism of the broadly Cartesian sort is a logical consequence of the turn to mechanism that defined the scientific revolution.

The only way to hold on to the mechanistic conception of nature while rejecting dualism is thus to deny the existence of intentionality. And that is why, as John Searle has argued, all extant forms of materialism do indeed implicitly deny its existence, and thus (I would say) amount to disguised forms of eliminative materialism. This is halfway admitted by Jerry Fodor when he writes, as he does in Psychosemantics, that “if aboutness [i.e. intentionality] is real, it must be really something else.” That is to say, intentionality per se simply cannot be real given the mechanistic conception of the material world that Fodor, like all materialists, has inherited from the early modern philosophers. Hence the most the materialist can do is try to substitute for it some physicalistically “respectable” ersatz. But this is simply eliminative materialism in “folk psychological” drag; and eliminative materialism, however you dress it up, is simply incoherent. (Yet again, see TLS, and in particular chapter 6, for the details.)

We have, then, another brief argument for dualism, which can be summarized as follows: If materialism is true, then (given that it is committed to a mechanistic conception of the material world), there are no final causes, and thus nothing that inherently “points to” or is “directed at” anything beyond itself; and in that case, there can be no such thing as intentionality; but there is such a thing as intentionality; therefore materialism is not true.

This is an argument for dualism, I should say, at least if one admits that the material world exists in the first place (which, of course, everyone other than a few adherents of idealism would admit), because it implies that there are features of the world other than its material features. The only way to avoid the dualistic consequences (other than opting for eliminativism or idealism) would be to acknowledge that the Aristotelians were right after all, and that final causes are a real feature of material reality. But that would, of course, be to abandon the entire modern mechanistic-cum-materialistic interpretation of science. Nor would it really stave off dualism for long, for it would simply open the door to the Thomistic or hylemorphic (as opposed to Cartesian) version of dualism. But that is a story for another time – a story which, like other details of the argument sketched here, can be found (if I might be forgiven one more shameless plug) in The Last Superstition.

Vallicella on hylemorphic dualism

Hylemorphic dualism is the approach to the mind-body problem taken by Aquinas and the Thomist tradition more generally.  (The label may have been coined by David Oderberg, who defends the view in an important paper and in his book Real Essentialism.  “Hylemorphic” is sometimes spelled “hylomorphic,” though the former spelling is arguably preferable since it is closer to the Greek root hyle.)  The view holds both that the soul is the substantial form of the living human body (that is the “hylemorphic” part) and that it is unique among the forms of material things in being subsistent, that is, capable of surviving beyond the death of the body (that is the “dualism” part).  Our friend Bill Vallicella has recently put forward the following criticism of the view:

Schrödinger, Democritus, and the paradox of materialism

Erwin Schrödinger was yet another of those early twentieth-century thinkers cognizant of the deeply problematic character of the mechanistic conception of the material world inherited from the early modern period – and yet another to see, in particular, that this conception of matter, far from opening the way to a materialistic solution of the mind-body problem, in fact created the problem and appears to make any materialistic solution to it impossible.

The reason does not (as one might suppose) have anything essentially to do with quantum mechanics, of which Schrödinger was one of the fathers. It has rather to do with a relatively simple philosophical point which was first made by the likes of Cudworth and Malebranche and repeated in recent years by writers like Nagel and Swinburne (as noted in the second of the earlier posts linked to above). Two relevant texts are Schrödinger’s essay “On the Peculiarity of the Scientific World-View” (from What is Life? and Other Scientific Essays) and chapter 6 of his Mind and Matter, entitled “The Mystery of the Sensual Qualities” (reprinted in What is Life? with Mind and Matter and Autobiographical Sketches – a more recent volume which does not include the earlier essay).

To summarize what I’ve said at greater length in earlier posts, the philosophical point in question is that the early moderns’ move of redefining matter so that it is devoid of color, odor, taste, sound, and the like as common sense understands them necessarily made these sensory qualities inexplicable in materialistic terms. Hence, if one is going to affirm the existence both of matter (as redefined by the moderns) and of the sensory qualities (or “qualia,” as they have come to be known, relocated from the external world to the internal world of the mind), then it seems one is necessarily committed to mind-body dualism of some sort (whether substance dualism or property dualism). The only way to avoid such dualism is either to reject the existence of matter (as Berkeley did), to reject the existence of the sensory qualities (as eliminativists do explicitly and most other materialists do implicitly), or to reject the mechanistic conception of matter that led to the problem in the first place (as Aristotelians do; though Aristotelianism still leads to a non-Cartesian form of dualism – what David Oderberg calls hylemorphic dualism – for reasons that have nothing to do with sensory qualities or qualia).

To be sure, Schrödinger himself does not explicitly draw an anti-materialist conclusion. He notes merely that what he calls the “objectivation” of matter – the conceptual removal from it of anything that smacks of the personal or of mind (cf. Thomas Nagel’s “objective/subjective” distinction) – makes the mind itself deeply mysterious. This is compatible with views like Colin McGinn’s “mysterianism” or Joseph Levine’s “explanatory gap” position, which affirm materialism even as they deny that we can understand, or at least (in Levine’s case) that we do in fact understand, how materialism can be true. Not that Schrödinger himself affirms this kind of view either; he simply calls attention to the problem raised by the modern conception of matter without trying to resolve it. (For my part, I consider McGinn’s and Levine’s positions non-starters. You might as well say, in response to Gödel, “Maybe the consistency of a formal system containing computable arithmetic really is internally provable after all, and our minds are just constitutionally incapable of seeing how.”)

Schrödinger’s emphasis is also less on the mind-body problem per se than on the epistemological paradox he sees implied by the modern “objectivation” of matter. As he puts it in “On the Peculiarity of the Scientific World-View”:

We are thus facing the following strange situation. While all building stones for the [modern scientific] world-picture are furnished by the senses qua organs of the mind, while the world picture itself is and remains for everyone a construct of his mind and apart from it has no demonstrable existence, the mind itself remains a stranger in this picture, it has no place in it, it can nowhere be found in it. (p. 216)

That is to say, the picture modern science (as informed by an “objectified” mechanistic conception of matter) paints of the natural world presents it as devoid of the sensory qualities and of anything personal. And yet the picture itself exists only within the minds of persons – scientists themselves – and takes as its evidential base the senses, and thus the very sensory qualities it refuses to locate in nature.

This epistemological paradox was a major theme of E. A. Burtt’s The Metaphysical Foundations of Modern Physical Science (Burtt being, as I have noted before, one of several major early twentieth-century scholars who emphasized the problematic character of the mechanistic revolution, before this theme went down the academic memory hole sometime in the 1960s). But awareness of it goes back much farther than that – indeed (and as Schrödinger reminds us) all the way back to the 5th century B.C., and in particular to Democritus, one of the fathers of atomism. In a famous fragment, Democritus imagines a conversation between the intellect, which (as Democritus naturally assumed) must endorse the atomists’ banishment of the sensory qualities from nature, and the senses, which form the evidential basis for the atomist theory:

Intellect: “Color is by convention, sweet by convention, bitter by convention; in truth there are but atoms and the void.”

Senses: “Wretched mind, from us you are taking the evidence by which you would overthrow us? Your victory is your own fall.”

It must be emphasized that Democritus is, commendably, calling attention to a difficulty facing a theory that he himself endorses; and that we have no idea how, or even if, he tried to resolve it. It is by no means obvious that any materialist in the intervening millennia has done any better. Many of them have done worse; indeed, vulgar materialists of the New Atheist stripe typically show no awareness that there is a problem here in the first place. Unfortunately, this includes Daniel Dennett, a well-known philosopher of mind. Dennett explicitly endorses an eliminativist position vis-à-vis the sensory qualities (see e.g. his essay “Quining Qualia”) – which is to his credit insofar as (I would argue) any consistent materialist must ultimately be an eliminativist anyway. What is not to his credit is his utter blindness to the deep philosophical puzzles such a position opens up, his peddling of shameless caricatures of anti-materialist views, and in general his refusal to concede that opponents of materialism are motivated by serious philosophical concerns.

Schrödinger provides us with a plausible account of the origins of this sort of blindness (in scientists, anyway – philosophers like Dennett should know better). In “The Mystery of the Sensual Qualities” he writes:

Scientific theories serve to facilitate the survey of our observations and experimental findings. Every scientist knows how difficult it is to remember a moderately extended group of facts, before at least some primitive theoretical picture about them has been shaped. It is therefore small wonder, and by no means to be blamed on the authors of original papers or of text-books, that after a reasonably coherent theory has been formed, they do not describe the bare facts they have found or wish to convey to the reader, but clothe them in the terminology of that theory or theories. This procedure, while very useful for our remembering the facts in a well-ordered pattern, tends to obliterate the distinction between the actual observations and the theory arisen from them. And since the former always are of some sensual quality, theories are easily thought to account for sensual qualities; which, of course, they never do. (p. 164)

In the case at hand, neuroscientists who begin, as every empirical scientist must, with observations – that is to say, with conscious experiences whose character is determined by various sorts of qualia or sensory qualities – go on to construct a theoretical description of the physical and neural processes associated with perception. This theoretical description then takes on, as it were, a life of its own, coming to seem as real or even more real than the concrete experiences that led to it, and the language in which the former is couched comes to be applied to the theorist’s description of the latter. Thus an explanation of “heat” in the sense of molecular motion comes to seem, especially when coupled with neuroscientific data, an explanation of “heat” in the sense of a certain kind of tactile sensory quality; an explanation of “red” in the sense of light of a certain wavelength comes to seem an explanation of “red” in the sense of a certain kind of visual sensory quality; and so forth.

But this is a muddle, a subtle committing of the fallacy of equivocation. The key theoretical concepts – molecular motion, light wavelengths, neural firing patterns, and so forth – are always understood in light of a broadly mechanistic conception of the natural world which follows the early moderns’ project of excluding final causes, sensory qualities and the like from matter and redefining it in abstract mathematical terms. To “explain” sensory qualities or qualia in such “scientific” (i.e. mechanistic and “objectified”) terms is thus really to change the subject. Earlier generations of philosophers and scientists realized this, which is why few of them were materialists – they saw that, by definition as it were, sensory qualities could not be “material” given the new conception of matter. But later generations – especially the current generation of scientists, who tend to be far more specialized and often seem less philosophically-minded or philosophically-educated than their predecessors – have forgotten this conceptual history. And this forgetfulness and philosophical shallowness together with the practical successes of modern science have hardened many of them – or at least the more vocal of the pop science writers among them – into a crude scientism which assumes that there are no philosophical problems, or at least no serious ones, which science is not capable of answering.

Thus, when philosophers come along – whether dualists or the more sophisticated and fair-minded sort of naturalist (e.g. a Searle, a Nagel, or a Chalmers) – and point out that existing neuroscientific “explanations” of consciousness and the like do not in fact explain the relevant phenomena at all, it comes to seem like these philosophers are inventing a new problem in a desperate and obscurantist attempt to salvage a belief in human dignity and specialness. In fact they are simply calling attention to a very old problem that the mechanistic theoretical model itself has created, and of which earlier generations of philosophers and scientists were well aware. In fact it is scientism which fosters obscurantism, ignoring as it does clear conceptual distinctions and forcing all intellectual life into a methodological procrustean bed. And in fact the mechanistic “objectified” conception of matter inherited from the early moderns is not a scientific discovery at all but a philosophical posit, and one which creates philosophical problems rather than solves them.

Obviously I am not claiming to establish these large claims here. (Doing so is in large part what The Last Superstition is about.) And obviously there are different moves a materialist might try to make in order to get around the problems in question (though, equally obviously, I don’t myself think any such moves can succeed). The point is that the problems are real ones, and serious ones. Any naturalist who dismisses them as motivated by irrational religious fanaticism is either ignorant or dishonest; certainly Democritus, Schrödinger, Burtt, Searle, Nagel, Chalmers et al. have no theological ax to grind. It goes without saying that our knowledge of the human brain has come a very long way since the 5th century B.C. But philosophically speaking, the history of materialism from Democritus to Dennett marks a precipitous decline.

Addendum 9/14: It occurs to me on re-reading the post that the Chalmers reference in the first sentence of the second-to-last paragraph is, coupled with the “or,” unintentionally misleading: Chalmers is a naturalist, but he is also a dualist of sorts. My apologies. The conceptual lay of the land vis-à-vis this subject is extremely complex, the range of possible positions is very large, and it is difficult briefly to summarize the issues without oversimplification – especially when (as was the case with this post) one is writing late on a Saturday night!

Vallicella on intentionality and potentiality

Over at Maverick Philosopher, Bill Vallicella takes note of some important analogies between, on the one hand, the potentialities and dispositions we find in material world, and on the other hand, the intentionality that Brentano famously took to be the mark of the mental. I pretty much endorse everything he says; indeed, Bill’s observations dovetail nicely with some of what I say in the second of my recent posts on dualism.

Still, in reply to that post, Bill today comments:

“What is less clear to me is whether intentionality strictly speaking is to be found in the material world, as Ed suggests in the first paragraph, or whether it is only something analogous to intentionality, a sort of proto-intentionality, that is found in the material world. My recent defense of the Potentiality Argument against the moral acceptability of abortion commits me to holding that there are irreducible potentialities in nature below the level of conscious mind. And perhaps this should soften me up for hylomorphic dualism, which is Ed's preferred solution to the mind-body problem. But I find some difficulties with hylomorphic dualism.”

In response, I would say, first of all, that I suppose it depends on what one means by “intentionality.” The Brentano-inspired definition Bill makes use of in his original post makes reference only to “aboutness” or directedness toward an object. And if that is all that intentionality entails, then it seems to me that the position I endorse, but also the position Bill defends, does indeed imply that intentionality exists in the material world below the level of consciousness, wherever potentialities and dispositions (or “potencies” and “powers” as we Aristotelian Scholastics would say) are found. Interestingly, this is a view that is coming to be taken seriously by thinkers well outside the orbit of either the Aristotelian-Thomistic-Scholastic family of views to which I am partial, or the more general blend of traditional metaphysical views to which Bill is sympathetic. David Armstrong, for example, has suggested that dispositions manifest a kind of “proto-intentionality.” The late George Molnar argued that causal powers cannot be understood except as instances of what he called “physical intentionality,” to distinguish it from the sort of intentionality mental states exhibit. The biologist J. Scott Turner argues that we must attribute a kind of “intentionality” to certain biological processes if we are to make sense of the distinction between the normal development of an organism and aberrant growth patterns. These are just a few examples; and in my view they support the conclusion that the Aristotelian-Scholastic notions of potencies, powers, and final causes are not only defensible today, but are in fact surprisingly widely defended today, even if those doing the defending often do not realize (given differences in jargon and certain false assumptions about what the Scholastics believed) that that is what they are doing. (I discuss this issue at length in The Last Superstition.)

Of course, given its typical usage, the term “intentionality” does smack of mentality, so that the idea of “intentionality below the level of consciousness” might seem jarring. And the medievals from whom Brentano derived the term did indeed use “intentional” as a way of characterizing the objects of the intellect. (To describe the phenomena Bill, along with Armstrong, Molnar, Turner, et al. are interested in, the medievals would just have spoken of potencies, powers, final causes, and the like, not intentionality.) So it is certainly defensible to suggest that “intentionality” be reserved to describe the kind of directedness that is associated with grasping something with the intellect (as we do but physical objects manifesting potentialities, dispositions, etc. do not), and perhaps more generally to describe the sort of directedness that animals exhibit in their various states of conscious awareness (as even creatures without intellects can do). In short, it seems to me that if there is a difference between Bill and me over the existence of intentionality below the level of mind, it is probably a verbal one.

Regarding hylomorphic dualism (or “hylemorphic” dualism, as it is sometimes spelled), I suppose someone could in theory accept the existence of irreducible dispositions, final causes, and the like without going the whole hog for Aristotelian hylemorphism and the sort of dualism thinkers like Aquinas would build on it. So we can bracket that question off for now. Still, it does seem to me that once one concedes the existence of inherent potentialities, powers, etc., then since these potentialities, powers, and the like are the potentialities, powers, etc. of certain kinds of thing (such embryos and acorns, to use Bill’s examples), one is also well on the way to conceding something like Aristotelian essentialism, which brings the question of hylemorphism onto center stage. But, again, that is a matter for another time.

The interaction problem, Part III

In a couple of previous posts (here and here) we have examined the famous “interaction problem” facing Cartesian dualism and its origins in the impoverished conception of causation the early modern philosophers put in place of the Aristotelian-Scholastic conception. But as Bill Vallicella rightly notes, whatever we think of the interaction problem and of Cartesian dualism’s ability to deal with it, it cannot be regarded as a reason for preferring materialism to dualism. For materialism faces an interaction problem of its own.

Part of the problem is that even if we identify mental events and physical events, mental properties seem to have no causal relevance. Suppose a sensation of pain is identical with such-and-such a neural firing pattern. The way it causes you to moan and to nurse the damaged body part is by triggering further neural processes which result in the flexing of the relevant muscles. In that case, though, it is the electrochemical properties alone that are doing the causal work, and the distinctively mental aspect – the experienced phenomenal character of the pain itself – seems epiphenomenal. This is called the “mental causation problem” and it is the aspect of the interaction problem for materialism that Bill focuses on. It arises in different ways for different varieties of materialism. (It threatens Donald Davidson’s anomalous monism, for example, because of his principle of the anomalism of the mental.)

But this isn’t the only way the interaction problem arises for materialism. It arises also because the mechanistic conception of the natural world makes body-body interaction as mysterious as mind-body interaction. And again, it does so because of the impoverished conception of causation the moderns put in place of the older Aristotelian-Scholastic conception.

The Aristotelian-Scholastic account of causation was rich in theoretical subtleties and carefully worked out distinctions. It included, not only the famous doctrine of the four causes – formal, material, efficient, and final – but also the act/potency distinction, the notion that causes and effects can sometimes be simultaneous, the distinction between causal series ordered per se and causal series ordered per accidens, the distinction between primary and secondary causes, the idea that causation involves the cause communicating something to its effect, an emphasis on substances rather than accidents or events as true causes, and so forth. But as Kenneth Clatterbaugh notes in The Causation Debate in Modern Philosophy 1637-1739, in the century or so between the time of Descartes’ work on the subject and that of Hume, virtually all of the characteristic theses of the Aristotelian-Scholastic account of causation were gradually abandoned. Of the four causes, only efficient causation was left, and in a radically modified form. Substances and their inherent causal powers were abandoned and causation was regarded instead as a relationship between events. Nothing was taken to be communicated from cause to effect and in principle anything might follow upon anything else.

What resulted, naturally, were the skeptical puzzles of Hume. The notion of causation as an objective feature of the world became problematic at best and unintelligible at worst. As I argue at length in The Last Superstition and Aquinas, and have discussed more briefly in earlier posts (e.g. here and here), this was inevitable given the abandonment of final causality. If there is nothing in a cause that inherently “points to” or is “directed at” the generation of a certain effect or range of effects, there is ultimately no way to make sense of the fact that it does indeed generate just that effect or effects.

Hence the fact that a material cause brings about just the material effect or effects it does becomes no less mysterious on the modern, mechanistic account of nature than mind-body interaction does. This is the reason bizarre theories like occasionalism and pre-established harmony had the cachet they did among some of the early moderns. The motivation was not, as is sometimes supposed, to find a way to salvage mind-body dualism. It was rather to find a way to deal with the fact that any causation at all in the natural order – even that between material bodies – seemed impossible given the new conception of nature.

But haven’t many contemporary philosophers tried to solve the puzzles about causation raised by the early modern philosophers, especially Hume? Indeed they have, but as I have shown in TLS and Aquinas, when they have attempted to provide a realist account of causation, the tendency has been to appeal to notions – inherent causal powers, “physical intentionality,” dispositions, and so forth – which essentially involve a return to something like an Aristotelian conception of nature. Clatterbaugh cites the example of Wesley Salmon, who in Four Decades of Scientific Explanation argues that genuine causal processes involve a “transmission” of “information,” and even of “structure,” from cause to effect. Like some of the other contemporary writers I’ve cited before (Armstrong, Molnar, et al.), Salmon does not realize that he sounds like a Scholastic.

The “interaction problem,” then, is not a problem for Cartesian dualism per se but for modern metaphysical positions in general, including materialism. Accordingly, its existence has no tendency whatsoever to provide an argument in favor of materialism over dualism. What it does provide is an argument in favor of a broadly Aristotelian-Scholastic metaphysics over any modern, mechanistic would-be replacement.

Nagel and his critics, Part II

Whereas my First Things review of Thomas Nagel’s Mind and Cosmos accentuated the positive, the first post in this series put forward some criticisms of the book.  Let’s turn now to the objections against Nagel raised by Brian Leiter and Michael Weisberg in their review in The Nation.  

First some stage setting is in order.  As I indicated in the previous post, Mind and Cosmos is mostly devoted to the positive task of spelling out what a non-materialist version of naturalism might look like.  The negative task of criticizing materialist forms of naturalism is carried out in only a relatively brief and sketchy way, and here Nagel is essentially relying on arguments he and others have developed at greater length elsewhere.  Especially relevant for present purposes is a line of argument Nagel put forward in what is perhaps his most famous piece of writing -- his widely reprinted 1974 article “What Is It Like to Be a Bat?” -- and developed further in later works like The View From Nowhere.

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.