Popper’s World 3

The Self and Its Brain: An Argument for Interactionism, a long exchange between philosopher Karl Popper and neuroscientist John Eccles, is among the most significant 20th century defenses of mind-body dualism. I do not agree with every aspect of their approach, but the book is filled with interesting things and deserves more attention than it has received in contemporary philosophy of mind.

Popper famously distinguished between three “worlds” or levels of reality. (Though whether “levels” of reality is the right gloss on Popper’s theory is not clear. “Kinds”? “Aspects”?) World 1 is the world of physical entities and states – tables, chairs, rocks, trees, fundamental particles and forces, human bodies and behavior, and so forth. World 2 is the world of thoughts, sensations, and mental phenomena in general. World 3 is the world of scientific and philosophical theories, arguments, stories, social institutions, works of art and the like. World 3 differs from World 1 in that the entities comprising it are abstract; for example, though a theory or argument might be embodied in a particular book (a World 1 object) it does not depend for its reality on the existence of that book, or on any book or World 1 object at all. We could still consider the Pythagorean theorem, know it to be true, prove it, etc. even if every geometry textbook that had ever existed were destroyed. World 3 differs from World 2 in being objective or public, whereas World 2 is subjective or private. Your thoughts and experiences are directly knowable only to you, but World 3 objects are equally accessible to everyone.

The objectivity or “autonomy” of such World 3 objects as theories and arguments is especially evident in Popper’s view from the fact that they have logical relations – and in particular, unforeseen implications and unnoticed inconsistencies – that may not be noticed until well after we first consider them, but which were evidently there all the time waiting to be discovered. Naturally, he takes mathematics to illustrate the point vividly, but it is in his view no less evident from empirical scientific theories. The clearest mark of the reality of all three worlds is in Popper’s judgment the fact that World 3 has a causal influence on World 1, and does so only via World 2. For example, the scientific theories which entailed the possibility of nuclear weapons have had an obvious impact on the material world – they have resulted in various nuclear tests, in the destruction of Hiroshima and Nagasaki, and so forth – but only because scientists carried out the mental activity of working out the implications of the theories and applying them.

Popper’s World 3 is often compared to Plato’s realm of the Forms, and Popper himself acknowledges that there are similarities. But he also emphasizes the significant differences between his view and Plato’s, not the least of which is that he takes World 3, despite its objectivity or autonomy, to be something “man-made,” its objects in the strict sense being what the human mind “abstracts” from their World 1 embodiment. Though Popper does not take note of the fact or develop the theme in much detail, this is clearly reminiscent of an Aristotelian or “moderate realist” approach to the traditional problem of universals, as distinct from the “extreme realism” of Platonism. (See here and here for a useful short account of the traditional Aristotelian-Thomistic-Scholastic approach to the issue and its significance.)

In other ways too Popper’s views as expressed in The Self and Its Brain overlap to some extent with Aristotelian ones. The emphasis on abstract thought – and thus on what is unique to human beings – as what is of greatest interest in the debate over dualism is very much in line with the classical Platonic-Aristotelian-Scholastic approach to this subject, which is quite different from the contemporary obsession with “qualia” and the like. There is also Popper’s acknowledgement of the reality of “downward causation” in physical systems and his consequent rejection of physicalistic reductionism even where non-mental phenomena are concerned. And there is his affirmation of the existence of objective “propensities” in nature, which (possibly) hints at something like the Aristotelian notion of potencies. (Though these last two themes take us beyond the World 3 thesis itself.)

On the other hand, there are some decidedly un-Aristotelian themes in Popper as well. There is, for instance, his denial of substance in favor of a “process” conception of the material world; and there is his rejection of essentialism, which he seems to assume is inherently Platonistic and committed to an a priori or “armchair” methodology. (This is a serious misunderstanding, and a very common one, which we Aristotelian-Thomistic (A-T) types find it rather tiresome constantly to have to rebut. See Oderberg’s Real Essentialism for the most thorough rebuttal, and pp. 30-38 for a reply to Popper specifically.)

All the same, any Aristotelian must admire the non-ideological character of Popper’s approach to the mind-body problem. Unlike so many contemporary philosophers of mind, he does not fatuously pretend that a presumption in favor of materialism has somehow been established by modern science, or that dualism rests on “intuitions” or the like. He does not present the problem situation as if it were a matter of determining whether we ought to wedge the evidence of our ordinary experience into the Procrustean bed of naturalism or instead to lop it off entirely – as if these were the only alternatives worth taking seriously. Nor does he have any theological ax to grind; he deliberately avoids getting into the question of the soul’s immortality (and even expresses the view that he would prefer not to be immortal). He merely observes that reality clearly comprises at least the three sorts of thing in question and that any serious solution to the mind-body problem will simply have to accommodate this plain fact. As The Self and Its Brain shows, Popper is also much better informed about the actual history of the mind-body problem than contemporary naturalists tend to be. (As my series of posts on Paul Churchland indicated, many naturalists seem unfamiliar with anything other than the crudest caricatures of what non-naturalist philosophers of mind have actually said.)

In short, at least where the mind-body problem is concerned, Popper does not attack straw men and he respects Butler’s famous dictum that “Everything is what it is, and not another thing.” (I put to one side for present purposes Popper’s views in political philosophy and philosophy of science, contexts in which he is more open to criticism on these grounds.) He thereby stands acquitted of a charge John Searle raised in The Rediscovery of the Mind against his fellow contemporary philosophers of mind:

[W]e let our research methods dictate the subject matter, rather than the converse. Like the drunk who loses his car keys in the dark bushes but looks for them under the streetlight, "because the light is better here,” we try to find out how humans might resemble our computational models rather than trying to figure out how the conscious human mind actually works…

[W]e ought to stop saying things that are obviously false. The serious acceptance of this maxim might revolutionize the study of the mind. (p. 247)

Like Searle, Popper is in my estimation better as a critic than as a positive theorist. (I discussed an important anti-materialist argument of his in an earlier post.) Still, from an A-T point of view even his positive theorizing is closer to the mark than that of most other contemporary dualists.

When Frank jilted Mary

We had reason recently to allude to Frank Jackson’s famous “knowledge argument” against physicalism. You’ll recall that the argument goes like this: Physicalism claims that if you know all the physical facts that there are to know about people, then you know all the facts there are to know about them, period; for human beings are (says the physicalist) entirely physical. But now consider Mary, a master neuroscientist of the future. Mary has lived her entire life in a black and white room, and has never had any experiences of colors. Still, having studied all the relevant neuroscientific literature, she knows everything there is to know about the physics and physiology of color perception. Hence she knows, for example, everything there is to know about what goes on in someone’s brain when he sees a red object, everything there is to know about the surface reflectance properties of red objects, and so forth. Now imagine that she leaves her black and white room and sees a red object herself for the first time. Does she learn something new? Surely she does – she learns what it’s like to see red. But then, physicalism is false. For though Mary knew all the physical facts about human perceptual experience before she left the room, she didn’t know all the facts, since she learned something when she left the room. Hence there are facts about human nature, and in particular facts about conscious experience, that escape the physicalist story – namely facts about “qualia,” the subjective features of a conscious experience in virtue of which there is “something it is like” to have that experience.

Jackson first presented this argument is his 1982 paper “Epiphenomenal Qualia,” and repeated it in 1986 in “What Mary Didn’t Know.” (There were several precursors to the argument, such as Thomas Nagel’s “What is it like to be a bat?”, and similar but independently developed ideas, such as Howard Robinson’s deaf scientist example in his 1982 book Matter and Sense.) The argument has generated an enormous literature. Some of it is collected in the Ludlow, Nagasawa, and Stoljar edited volume There’s Something About Mary: Essays on Phenomenal Consciousness and Frank Jackson’s Knowledge Argument. You will find there also some later essays by Jackson in which he expresses second thoughts about the argument; for by the late 1990s he had recanted and embraced physicalism.

Why? For no good reason, in my view; nor in the view of Jackson’s fellow “knowledge argument” proponent Howard Robinson, whose (characteristically excellent) essay “Why Frank Should Not Have Jilted Mary” offers a penetrating critique of Jackson’s current views. (You can read part of Robinson’s article here, though the anthology in which it appeared – Edmond Wright’s The Case for Qualia – is well worth the purchase price.)

As Stoljar and Nagasawa note in their introduction to There’s Something About Mary, “the argument, [the later Jackson] said, contained no obvious fallacy, and yet its conclusion – that physicalism is false – must be mistaken” (p. 23). Again, why? We might distinguish two components of Jackson’s current position. First, there is Jackson’s justification for claiming that something or other must be wrong with the knowledge argument, even if it seems to be perfectly cogent; and second, there is his strategy for explaining away the apparent cogency of the argument by suggesting where a fallacy is most likely to be found in it. The second component involves appeal to a “representationalist” theory of consciousness, and interested readers will find in Robinson’s essay a useful discussion of the problems with Jackson’s application of this theory. (For my money the main problems are two: First, representationalism is, at the end of the day, merely a riff on functionalism, and thus cannot serve to rebut the knowledge argument any more than – by Jackson’s own lights pre-recantation – older versions of functionalism could. Second, the key notion of “representation” itself cannot be accounted for in physicalist terms, so that even a successful representationalist analysis of consciousness could not vindicate physicalism.)

But it is the first component of Jackson’s current position – and some remarks of Robinson’s that are relevant to it – that I want to focus on here. In his 2002 essay “Mind and Illusion” (available in the Ludlow, Nagasawa, and Stoljar volume), Jackson tells us that:

Much of the contemporary debate in the philosophy of mind is concerned with the clash between certain strongly held intuitions and what science tells us about the mind and its relation to the world. What science tells us about the mind points strongly towards some version or other of physicalism. The intuitions, in one way or another, suggest that there is something seriously incomplete about any purely physical story about the mind.

For our purposes, we can be vague about the detail and think broadly of physicalism as the view that the mind is a purely physical part of a purely physical world. Exactly how to delineate the physical will not be crucial: anything of a kind that plays a central role in physics, chemistry, biology, neuroscience, and the like, along with the a priori associated functional and relational properties, count, as far as we are concerned.

Most contemporary philosophers, when given a choice between going with science and going with intuitions, go with science. Although I once dissented from the majority, I have capitulated and now see the interesting issue as being where the arguments from the intuitions against physicalism – the arguments that seem so compelling – go wrong. (p. 421)

This is a remarkable passage – remarkable for the breathtaking rhetorical sleight of hand it embodies. I do not mean to imply that Jackson is being insincere or intentionally manipulative of his readers; I am sure he is not. But – with all due respect to a philosopher whose work I have long admired, and still admire – that is only because he has evidently now “drunk the Kool-Aid” of physicalism so deeply that he is perhaps incapable of seeing how thoroughly tendentious and question-begging is his characterization of the philosophical situation.

Consider the way Jackson frames the issue here – as a debate between “science” and “intuition.” If that really were what the debate is about, how could any rational person fail to understand why Jackson has come to endorse physicalism? Indeed, how, in that case, could any rational person fail to join him in that endorsement? But in fact that is not what the debate is about; certainly Jackson has given us no reason to think it is. Jackson’s younger self certainly didn’t appeal to “intuition.” There is no such appeal in the formulation of the knowledge argument I presented above, and there is no such appeal in Jackson’s presentation in the two articles in which he first put forward the argument. Indeed, in “Epiphenomenal Qualia,” Jackson explicitly says that it is “unfair” to suggest that a qualia-based objection to physicalism must rest on an unargued intuition, explicitly distances himself from the “modal argument” against physicalism precisely because he takes it to rest on a disputable intuition, and explicitly favors the knowledge argument precisely because he there takes it to embody something more firm than an appeal to disputable intuitions!

Consider too that both sides can play the game Jackson is playing in the passage under consideration. The anti-physicalist could say:

We know from the very nature of “the physical” as that tends to be understood in contemporary philosophy that there can in principle be no physicalistic explanation of conscious experience. Arguments like the knowledge argument illustrate this point. And yet many contemporary philosophers have a strongly held intuition that a scientific view of the world requires a commitment to physicalism. Still, other contemporary philosophers, when given a choice between going with solid philosophical arguments and going with disputable intuitions, go with the solid philosophical arguments. Accordingly, they reject physicalism as a misinterpretation of science.

Is this as plausible as Jackson’s way of framing the issue? I maintain that it is far more plausible. And this brings us to the other problem with the passage from Jackson under consideration. Jackson casually assures us that “what science tells us about the mind points strongly towards some version or other of physicalism.” Physicalists say this all the time, of course. But it isn’t true, and Jackson certainly gives us no reason whatsoever to think that it is true. In fact, modern science points solidly away from physicalism, and the reason has precisely to do with the very issue Jackson thinks is “not crucial,” viz. “exactly how to delineate the physical.” For as I have noted in many places – most recently in a post on Chomsky – notions like “matter” and “the physical,” though they have (as Chomsky has rightly emphasized) at best a very elusive positive content in most modern thinking on the mind-body problem, nevertheless have also a very clear negative content. As I stated in the Chomsky post:

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.

This lesson, I submit, is precisely what Jackson’s original knowledge argument illustrates. It shows in a new way what early modern philosophers like Descartes, Cudworth, Malebranche, and Locke, and contemporary thinkers like Nagel and Swinburne, already knew and pointed out many times over the centuries – that given the (mechanistic) understanding of “the physical” that all modern philosophers (whether they be Cartesians, idealists, or materialists) tend to take for granted, a “physicalistic” explanation of consciousness is in principle impossible. It is the moderns’ very conception of matter, rather than some “disputable intuition,” that opens the way to dualism. And insofar as modern science has committed itself to this conception of matter, it follows that modern science itself points to dualism and away from physicalism. I hasten to add, though, that this commitment is not really a “scientific” commitment at all, but a purely philosophical one.

And a mistaken one too, from the point of view of Aristotelian-Thomistic philosophers like myself. This brings me to some important remarks from Robinson’s essay. Robinson says:

The dialectical situation in which the knowledge argument is usually taken to be located is the following: it is accepted that physicalism gives an adequate account of non-conscious reality, which constitutes almost 100 percent of the universe, but struggles to accommodate certain features of mental life, namely the “what it’s like” or qualia of certain conscious states. These latter constitute “the hard problem” for physicalism. The fact that they also constitute such a tiny part of the world is presented as a reason for thinking that they cannot plausibly be held to refute a unified physicalist account.

I think that this constitutes a radical misunderstanding of the dialectical situation. What the argument really brings out is that only experience of the appropriate kind can reveal the qualitative, as opposed to purely formal and structural, features of the world. The kind of thing that Mary did not know, generalized from color vision to all the other sensible qualities, is essential to any contentful conception of the world, and physicalism without it would lack any empirical content. (p. 240)

There are two themes here that I want briefly to develop. The first is the entirely illusory character of the widespread assumption that “everything else has been given a physicalistic explanation,” so that the mind cannot plausibly be regarded as immune to such explanation. In fact, the reason it seems that “everything else has been given a physicalistic explanation” is precisely the reason that the mind cannot be “explained” in the same way. For “everything else” has been “explained” in a physicalistic manner precisely by carving off the aspects of mind-independent reality that do not fit the physicalistic model and relocating them in the mind, treating them as mere projections. Again, color, odor, sound, taste, heat, cold, and the like, as common sense understands them, were “explained” only by denying that these qualities really exist in the external physical world at all in the first place. Instead, color, odor, sound, and the rest were for purposes of physics redefined in physicalistically “respectable” terms – color in terms of surface reflectance, sound in terms of compression waves, and so on. Color, sound, etc. as common sense understands them were then reinterpreted as existing only in our conscious experience of the material world, rather than in the material world itself. In short, they are not truly “explained” at all, but just swept under the rug of the mind. (As I have argued before, the problem intentionality poses for physicalism has a similar origin.)

The early moderns generally recognized that this entails a kind of dualism – that it is simply incoherent to suppose that one can get rid of the sensory qualities so reinterpreted by further relocation and redefinition, any more than one can get rid of literal dirt that one has swept under a rug by further application of the “sweep it under the rug” strategy. Contemporary writers like Thomas Nagel see this too – see that it is precisely the physicalist’s own understanding of what “reductive explanation” involves that precludes in principle a “reductive explanation” of conscious experience itself. But contemporary physicalists, forgetful of the history of their discipline, cluelessly draw precisely the opposite conclusion: “Come on, we’ve gotten rid of all the other dirt in the room by sweeping it under the rug; so why wouldn’t we be able to deal with the dirt under the rug in the same way?”

The second theme from Robinson I want to call attention to is his suggestion that “only experience of the appropriate kind can reveal the qualitative, as opposed to purely formal and structural, features of the world.” What he is getting at is this. When the natural world is denuded of the qualitative features common sense takes it to have – color, odor, taste, sound, and the like, as we experience them in everyday life – what we are left with is an entirely abstract structure, the sort of thing physics expresses in the language of mathematics. But it is simply incoherent to regard the mind-independent world as nothing but an abstract structure; there must be something which has the structure. Moreover, to deny the existence of the qualitative features themselves – as some eliminative materialists have suggested doing as a way of “solving,” by brute force, the problem qualia pose for physicalism – would in effect be to cut off the scientific redefinition of nature from any empirical support at all. We would be denying, in the name of science, the very existence of the conscious experience from which scientific inquiry proceeds (a paradox that was not lost on the ancient Greek atomist Democritus, as I noted in an earlier post).

Bertrand Russell, E. A. Burtt, and other early twentieth-century thinkers were well aware of these problems. Russell’s solution was to suggest that the sensory qualities which the moderns had redefined as mere projections of the mind have to be put back into the natural world after all. Accordingly, something like what philosophers now call “qualia” were, for Russell, the intrinsic features of the external physical world – that which “fleshes out” or makes concrete the otherwise abstract structure described by physics. Contemporary philosophers like Michael Lockwood, David Chalmers, and Galen Strawson have followed Russell’s lead, and Robinson’s position seems to bear a family resemblance to theirs. The trouble is that, given the “mental” character modern philosophers tend to attribute to the sensory qualities, this Russellian approach seems to lead to a kind of idealism or panpsychism, on which the natural world is mental through and through (though Russell and Lockwood, at least, try to resist this consequence). This is, I think, a less mad view than physicalism is, but it is mad all the same.

From an Aristotelian-Thomistic point of view, the mistake was opting for a mechanistic-cum-quantitative conception of nature in the first place, and philosophers of mind have been on the wrong track ever since Descartes, Hobbes, and Co. The value of the knowledge argument is that it shows, as Robinson puts it, that “classical physicalism is broken-backed from the start” (p. 243). But Cartesian dualism, property dualism, idealism, panpsychism, etc. are at best only less bad than physicalism. The correct remedy is a full-blown return to Aristotelian-Thomistic hylemorphism, on which alone the quantitative picture of the world presented to us by modern science can properly be understood – as an important part of the correct story about the natural world, but never the whole story.

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.

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.]

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.

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.

Churchland on dualism, Part III

To conclude our look at Paul Churchland’s critical discussion of dualism in his textbook Matter and Consciousness, let’s consider the arguments he presents against dualism. There are four of them, and they can be summarized as follows:

1. The argument from Ockham’s razor: Postulating two basic kinds of substance, material and immaterial, needlessly complicates our ontology if mental phenomena can be adequately explained in terms of material substance alone. That they can be so explained is indicated by the next two arguments:

2. The argument from the explanatory impotence of dualism: Materialist explanations can appeal to the many details of the brain’s structure and function revealed by modern neuroscience, while dualists have yet to provide a comparable account of the structure and function of immaterial substance.

3. The argument from the neural dependence of all known mental phenomena: As both everyday experience and neuroscientific research show, reasoning, emotion, and consciousness are all very closely correlated with various processes in the brain, which is not what we would expect if these mental phenomena were associated with an immaterial substance.

4. The argument from evolutionary history: The evolutionary process that gave rise to the human species proceeded via purely material mechanisms from a purely material starting point, so that the end result must itself be purely material.

Churchland acknowledges that none of these arguments is by itself absolutely conclusive. But he does think the third one “comes close to being an outright refutation of (substance) dualism,” and he clearly believes that in tandem the arguments consign dualism to the dustbin for all practical purposes. No doubt most materialists would agree with him. But in fact these arguments have, I maintain, no force at all against dualism. None. Dualism may or may not in fact be true – obviously I think it is true, but that is another issue. The point is that, even if it were false, these arguments have no tendency to show that it is.

How can I say that? Easy. Keep in mind first of all that, as I have emphasized in the earlier posts in this series, the chief proponents of dualism historically have not defended their position as an “explanatory hypothesis” put forward as the “best explanation” of the “empirical data.” That just isn’t what they are up to, any more than geometers or logicians are. They are attempting instead to provide a strict demonstration of the immateriality of the mind, to show that it is metaphysically and conceptually impossible for the mind to be something material. Their attempts may or may not succeed – again, that is another question. But that is what they are trying to do, and thus it simply misses the point to evaluate their arguments the way one might evaluate an empirical hypothesis. When Andrew Wiles first claimed – correctly, as it turned out – to have proven Fermat’s Last Theorem, it would have been ridiculous to evaluate his purported proof by asking whether it best accounts for the empirical evidence, or is the “best explanation” among all the alternatives, or comports with Ockham’s razor. Anyone who asked such questions would simply be making a category mistake, and showing himself to be uninformed about the nature of mathematical reasoning. It is equally ridiculous, equally uninformed, equally a category mistake, to respond to Plato’s affinity argument, or Aristotle’s and Aquinas’s argument from the nature of knowledge, or Descartes’ clear and distinct perception argument, or the Cartesian-Leibnizian-Kantian unity of consciousness argument, or Swinburne’s or Hart’s modal arguments, or James Ross’s argument from the indeterminacy of the physical, by asking such questions. As with a purported mathematical demonstration, one can reasonably attempt to show that one or more of the premises of such metaphysical arguments are false, or that the conclusion does not follow. But doing so will not involve the sorts of considerations one might bring to bear on the evaluation of a hypothesis in chemistry or biology.

Of course, Churchland, committed as he is to a Quinean form of scientism, thinks that all good theories must in some sense be empirical scientific theories. He rejects the traditional conception of metaphysics as a rational field of study distinct from and more fundamental than physics, chemistry, biology, and the like, and would deny that there is any such thing as sound metaphysical reasoning that is not in some way a mere extension of empirical hypothesis formation. But he cannot simply assume all of this in the present context without begging the question, because this sort of scientism is precisely (part of) what the dualist denies. (As we have seen in earlier posts on naturalism, this kind of circular reasoning is absolutely rife in naturalist thinking.)

It is obvious, then, why Churchland’s first two arguments have no force, for they simply misconstrue the nature of the case for dualism. If any of the dualist arguments just mentioned works, then the immateriality of the mind will have been demonstrated, and asking “But do we really need to postulate immaterial substance?” or “How much can we really know about such substances?” would not be to the point. For we would not in that case be hypothetically “postulating” anything in the first place, but directly establishing its existence; and its existence will have been no less established even if we could not say much about its nature.

But this brings us to an additional problem with Churchland’s second argument, which further underlines just how embarrassingly uninformed he is about what dualists have actually said. In developing his “explanatory impotence” objection, Churchland complains that dualists have told us very little about the nature of “spiritual matter” or the “internal constitution of mind-stuff,” about the “nonmaterial elements that make it up” and the “laws that govern their behavior.” This is, for anyone familiar with the thought of a Plato, an Aquinas, a Descartes, or a Leibniz, simply cringe-making. The soul is not taken by these writers to be “made up” out of anything, precisely because it is metaphysically simple or non-composite. It is not a kind of “stuff,” it is not made out of “spiritual matter” (whatever that is), and it is not “constituted” out of “elements” which are related by “laws.” Nor is this some incidental or little-known aspect of their position – it is absolutely central to the traditional philosophical understanding of the soul. As is so often the case with naturalistic criticisms of dualism, theism, etc., Churchland’s argument is directed at a breathtakingly crude straw man.

This appalling ignorance of the actual views of dualists manifests itself again in Churchland’s third argument. Churchland himself admits that this argument has no effect against property dualism, since property dualism itself takes the brain to be the seat of mental phenomena. But he fails to see that it has no effect against the other main varieties of dualism either, given what they actually say about the relationship between the mind and the brain.

For starters, let’s take Aristotelian-Thomistic (A-T) hylemorphic dualism. The A-T view is that the intellect is immaterial, but that sensation and imagination are not. Hence it is no surprise at all that neuroscience has discovered various neural correlates of mental imagery and the varieties of perceptual experience. Moreover, A-T holds that though intellect is immaterial, its operation requires the presence of the images or “phantasms” of the imagination. Hence it is no surprise that neural damage can affect even the functioning of the intellect. Most importantly, the soul, of which intellect, sensation, and imagination are all powers, is not a complete substance in its own right in the first place, but rather the form of the body. The way intellectual and volitional activity relates to a particular human action is, accordingly, not to be understood on the model of billiard ball causation, but rather as the formal-cum-final causal side of a single event of which the relevant physiological processes are the material-cum-efficient causal side. That alterations to the body have mental consequences is thus no more surprising than the fact that altering the chalk marks that make up a triangle drawn on a chalkboard affects how well the marks instantiate the form of triangularity. It is important to emphasize that none of this involves any sort of retreat from some stronger form of dualism, as a way of accommodating the discoveries of contemporary neuroscience; it is what A-T has always said about the relationship between soul and body. There is absolutely nothing in modern neuroscience that need trouble the A-T hylemorphic dualist in the slightest.

What about the Cartesian dualist? Don’t the differences between Descartes’ views and those of his Scholastic predecessors make him vulnerable to the findings of neuroscience in a way the latter are not? No, they don’t. For one thing, and as I have noted in an earlier post, Descartes’ views on this subject were not in fact quite as different from those of his predecessors as is often supposed. For example, Descartes’ view appears to have been that it is the intellect, specifically, which is to be identified with the ego he thinks is capable of existing apart from the body. Sensations, emotions, and the like he regarded, not as purely mental phenomena, but rather as hybrid properties which can be predicated only of the soul-body composite, and not the soul alone. Hence even on Descartes’ view it is not at all surprising that neuroscience has discovered all sorts of correlations between various aspects of perceptual experience and various emotional states on the one hand, and various processes in the brain on the other.

Now what is true is that the Cartesian has a difficulty explaining mind-body interaction that the A-T view does not have, as I have discussed here and here. And the reason is that Descartes rejected the notion that the soul is the formal cause of the body. That is an enormously consequential difference between the two views. But it has nothing to do with the specific question about whether a dualist need be troubled by the discovery of detailed correlations between mental phenomena and neural phenomena, which is what is at issue in the argument of Churchland’s under consideration. In particular, even the Cartesian need not be troubled by the fact that intellectual activity too (and not just sensation, emotion, and the like) can be dramatically affected by changes to the brain.

Why not? For one thing, as Churchland himself admits, the Cartesian regards the brain as a “mediator” between the soul and the rest of the body, so that we should expect that damage to this mediator will prevent the intellect from receiving the information it derives from the body and from controlling bodily behavior as well as it normally would.

But there is a deeper consideration. Consider the following analogy: A typed, written, or spoken token of the word “bark,” considered merely as a material object, has all sorts of complex physical properties, and those physical properties are highly relevant to its status as a word, as a bearer of linguistic meaning. Alter the physical properties of the token too radically, and it can no longer convey the meaning it once did. For example, if the ink should smear, the sound be muffled, or the power source to a word processor be cut off, the word will disappear, or might at least become so distorted that it becomes unintelligible. It would be absurd, though, for someone to suggest that these facts lend any support whatsoever to the claim that a word token qua word token is exhausted by its physical properties. It clearly is not. It is, for example, indeterminate from the physical properties alone whether the “bark” in question is the bark of a dog or the bark of a tree. Indeed, since the fact that the relevant sounds and shapes are associated with a certain meaning is entirely contingent, an accident of the history of the English language, it is indeterminate from the physical properties alone whether the word has any meaning at all. In short, the physical properties are a necessary condition for any particular physical object’s counting as a word token, but they are not a sufficient condition. And piling up bits of physicochemical knowledge about word tokens cannot possibly change this fact in the slightest, for it is a conceptual point about the nature of words, not an empirical point about what the latest research in phonetics (or whatever) has turned up.

In the same way, the dualist claims to be making a conceptual point about the relationship between mind and body, one to which neuroscientific research, important and interesting as it is in itself, is irrelevant. The existence of such-and-such physiological phenomena may well be a necessary condition for the existence of intentional human actions, intelligible speech, and so forth, but it is not and cannot be a sufficient condition. And that remains true whether we are interpreting dualism in A-T terms or in Cartesian terms. A-T regards the soul as the formal cause of a single substance of which the matter of the body is the material cause. Cartesians regard mind and matter as two distinct substances. Either way, there is not, and in principle cannot be, anything distinctively mental in matter as such, any more than a word token, considered merely as an arrangement of ink marks or a pattern of sound waves, has any meaning on its own. Or at least, there cannot be if dualism is correct. No amount of neuroscientific evidence can undermine this judgment, because what is at issue is whether any purely material phenomena at all, neurological or otherwise, can in principle be mental.

“But doesn’t that make dualism unfalsifiable?” If “unfalsifiable” means “not subject to rational evaluation and criticism,” then no, of course it isn’t unfalsifiable. Metaphysical arguments, like mathematical arguments, are perfectly susceptible of rational analysis and refutation, even if, like mathematical arguments, such analysis does not involve the weighing of probabilities, the comparison of alternative empirical hypotheses, etc. If “unfalsifiable” means instead “not subject to refutation via empirical scientific research,” then yes, dualism is unfalsifiable in that sense. But so is mathematics, and yet that doesn’t detract from its status as a rational field of investigation. Again, if the materialist wants to insist that all rational inquiry must ultimately be a kind of empirical scientific inquiry, he is welcome to make the case, but he cannot simply assume the truth of scientism when criticizing the dualist, otherwise he will simply be begging the question.

And that brings us, finally, to the fourth of Churchland’s arguments, the argument from evolution. Here again we have an argument that is entirely without force, and the main reason should be obvious from what has just been said: Dualism is a metaphysical theory, not an empirical hypothesis, and thus it is not the sort of thing that could be refuted by empirical biological findings any more than by neuroscientific ones.

But there is more to be said. Churchland’s fourth argument is also question-begging. For whether Darwinian evolution – which is supposed to be a purely materialist theory – is in fact a complete explanation of human nature depends on whether human nature is entirely material. And of course, the dualist’s claim is precisely that human beings are not and cannot be purely material, in which case no purely materialist theory could possibly provide a complete explanation of human nature. Hence it is no good to merely to assert, as an argument against dualism, that Darwinism has already explained human nature in materialist terms. That simply assumes the falsity of dualism without proving it.

Nor is it any good to stamp one’s feet and insist that if Darwinism entails materialism, then we had all better be materialists. Because here’s a newsflash: If Darwinism entailed that 2 + 2 = 5, what that would show is, not that 2 + 2 = 5, but that Darwinism is false, or at least needs to be seriously modified. Similarly, if Darwinism really does entail materialism, but the arguments of an Aquinas, a Descartes, or a James Ross show that materialism is false, then so much the worse for Darwinism. It had better adapt itself to the metaphysical facts, or be selected out. Like so many other naturalists, Churchland waves the “evolution” talisman as if it sufficed to shut off all debate, assuring us that in light of Darwinism we “are creatures of matter” and “should learn to live with that fact.” But this is sheer, question-begging bluff, not serious philosophical argument.

We have seen, then, over the course of these three posts, that Churchland’s treatment of dualism in Matter and Consciousness, though purporting to be a balanced summary, is in fact almost completely worthless both as a guide to what dualists have actually said and as a critique of dualism. And this is a textbook! And a widely used one, which has long been in print – it was one of the books I was taught out of as an undergraduate, and (I am ashamed to say) as a teacher I once used it myself. It took me many years to see just how bad it is. Most students who have read it probably have no idea, and never will.

But that’s how bad ideas spread: By ignorance and intellectual dishonesty smugly masquerading as expertise. Here, as with the debate over theism, the naturalistic skeptic can maintain the illusion of rational superiority only to the extent that he and his readers remain ignorant of what the great thinkers of the past have actually said. For to paraphrase Cardinal Newman, to be deep in history is to cease to be a naturalist.