Thursday, December 18, 2008


Ars Technica reports the following development in neuroscience (Hat tip: The Corner):

The advent of techniques like PET scans and functional MRI has enabled researchers to observe the brain in action with a precision that is unprecedented. One of the interesting aspects of these studies is that we can now actually perform a limited version of what might be called mind reading: identifying what's going on in the brain without having the owner of said brain describe it. In the latest development in the field of neuroimaging, researchers have watched the brain of someone watching an image, and were actually able to perform reasonable reconstructions of the image.

Pretty impressive. But does it amount to a kind of “mindreading,” as the author says? Does it show (what the author does not say, but which many readers will no doubt infer) that the having of a mental image can be identified with a certain kind of brain process? Not so fast. Here is a good example of how empirical discoveries which might seem to provide answers to philosophical questions actually presuppose such answers.

Notice first that no one who used fancy scientific instruments to observe the image on someone’s retina would regard this as an instance of “mindreading,” even though such an observation would under normal circumstances allow the observer to infer what sort of visual experience the subject was having. So why should observing some brain process associated with a certain sort of visual experience count as “mindreading”? The answer, of course, is that researchers assume there to be a connection between mental events and neural events that is more direct and intimate than that which exists between (say) mental events and events occurring within the eye.

Now that assumption may be correct – and I think it is in fact correct – but it is an assumption rather than something observed in the data, and more to the point it is an assumption with philosophical, and not just empirical, content. Recall my earlier post about Karl Popper’s critique of causal theories of the mind: Before we can identify any causal relation between the brain and the external world as having any sort of explanatory force vis-à-vis the mind, we have to be able to identify some particular external event as “the beginning” of the relevant causal chain, and some event within the brain as “the end.” Yet, as Popper argues, there is nothing in the bare empirical facts that can justify such identifications, nothing that determines this particular point as a “beginning” or that particular point as an “end.” (In the case at hand, there is nothing in the bare empirical facts that determines that it is such-and-such brain processes, rather than the image on the retina, or rather than some different event altogether, that counts as the terminus of the relevant causal chain.) Such identifications are interest-relative and thus non-objective – or at any rate they are, I would add, if we assume a “mechanistic” conception of the natural world.

To avoid the conclusion that they are interest-relative and non-objective (and the idealism or anti-realism this would seem to imply), we have to return to the Aristotelian idea that natural objects and processes have essences, that these essences entail inherent powers, and that these powers are defined by ends or goals toward which the objects or processes “point” as a final cause. In the case at hand, we have to assume (among other things) that the perceptual process inherently “points to” and thus of its nature terminates in, not the generation of a retinal image, not some set of neural events further down the line from the ones the researchers cited in the article were focusing on, but rather in those specific neural processes themselves. Here as elsewhere (as I argue at length in The Last Superstition), despite the “mechanistic” conception of nature officially and unreflectively endorsed by most scientists, the actual practice of empirical science, and certainly the intelligibility of its results, presupposes something like Aristotelian essentialism.

Secondly, it is also worth emphasizing that the researchers in question have (quite obviously) not literally been looking at any subject’s mental images or sensations. They have instead merely inferred from certain brain processes that the image must have such-and-such a character. Hence they have not discovered anything that need trouble any Cartesian dualist, since such dualists would (going back to Descartes himself) happily concede, and indeed emphasize, that there are neural processes causally correlated with various mental events, and insist only that the correlation does not and cannot entail that the relevant mental events are either identical with or metaphysically supervenient upon any neural events.

In any event, from an Aristotelian-Thomistic point of view, results of the sort cited in the article are not only no evidence against dualism, but indeed just the sort of thing we should expect. For unlike Cartesians, Aristotelians and Thomists regard sensation and imagination as entirely material processes, not immaterial ones. Hence even an outright identification of (and not just correlation between) the having of a perceptual experience or mental image and a certain neural event would be no evidence at all against the claim that the mind is immaterial. For the defining aspect of the mind is intellect, and intellect is irreducible to sensation, imagination, or indeed any other material process.

The main reason has to do with the differences between the objects of intellect on the one hand, and the objects of sensation and imagination on the other. For one thing, sensations and mental images are always concrete and particular, while the concepts grasped by the intellect are abstract and universal. A given mental image of a man, for example, is always going to have features that apply at most to many men, but never to men universally; it will be of either a fat or a thin man, of a bald man or a man with hair, of a tall man or a short man, etc., and thus be limited in its application in a way that the universal idea of man is not. Secondly, images are always vague and indistinct when their objects are more complex, while the ideas grasped by the intellect are clear and distinct however complex their objects. To take a famous example from Descartes, no mental image you can form of a chiliagon (a thousand-sided polygon) is clearly different from your mental image of a 997-sided figure or a 1001-sided figure, but the concept of a chiliagon grasped by your intellect is clearly different from the concept of a 997-sided figure or a 1001-sided figure. Thirdly, there are things we simply cannot form a mental image of which the intellect can nevertheless grasp the idea of: abstractions like economics, law, or love; temporal relationships; logical relationships like entailment, conjunction, disjunction, and negation; and so on.

Since the objects of the intellect differ in kind from mental images and sensations, it follows that to detect neural patterns of the sort described in the article, whether or not it amounts to “reading” what someone is sensing or imagining, does not and cannot amount to “reading” what is going on in their intellects, and thus does not and cannot amount to reading their thoughts, if we confine “thought” to what the intellect does when it makes judgments and inferences, which involve the grasp of concepts.

Might the detection of some other kind of neural pattern amount to “reading” someone’s thoughts? No, for (among other things) the reasons outlined in my series of posts on short arguments for dualism. In particular (as I argued here), given a mechanistic (i.e. final causality-denying) conception of the material world, any material process must be devoid of intentionality. But thoughts are inherently intentional. Hence nothing detectable in any purely material processes (again, where “material” is understood in mechanistic terms) could possibly reveal the content of any thought.

Now if we reject a mechanistic conception of the material world and acknowledge the existence of final causes, then a kind of intentionality does become detectable within the material world after all. But now another consideration comes into play. For (as I argued here) the specific kind of intentionality involved in conceptual thought still cannot be accounted for in material terms, because material processes are always inherently indeterminate while at least some of our thoughts are not. Conceptual thought, the characteristic activity of the intellect, is (unlike sensation and imagination) thus essentially immaterial. Hence its presence can never even in principle be detected merely by examining someone’s brain.

(As indicated in that earlier post, this is, as James Ross has pointed out, the upshot of arguments like Quine’s famous argument concerning the inscrutability of reference and Kripke’s “quus” argument, though materialist writers like Quine conclude, not that thoughts are therefore immaterial, but rather – and incoherently – that none of our thoughts has any determinate meaning. I say “incoherently” because – again, as Ross points out and as I said in the earlier post – to deny that we have any thoughts with determinate meaning is in effect to deny among other things that we ever reason in accordance with valid forms of inference, which undermines any argument anyone, including Quine himself, has ever given.)

This leaves it open that, at least given certain background assumptions, we might guess with some measure of probability what someone is thinking. Indeed, we can do that already, just by observing a person’s behavior and interpreting it in light of what we know about him in particular, his circumstances, human nature in general, and so forth. And of course, further knowledge of the brain might give us even further, and more refined, resources for making inferences of this sort. But what it cannot do even in principle is fix a single determinate interpretation of those thoughts, or reduce them entirely to neural activity. So, no entirely empirical methods could, even in principle, allow us to “read” someone’s thoughts in anything more than the loose and familiar sense in which we can already do so.


  1. Do you cover all this in more detail in your Philosophy of Mind book? I picked up The Last Superstition - I'm still wrestling with some of what you say, but I'm eager to learn more.

  2. Hi, while I don't address "mindreading" per se in Philosophy of Mind, I do get into the related issues discussed here, especially in the chapter on intentionality.

  3. """Recall my earlier post about Karl Popper’s critique of causal theories of the mind: Before we can identify any causal relation between the brain and the external world as having any sort of explanatory force vis-à-vis the mind, we have to be able to identify some particular external event as “the beginning” of the relevant causal chain, and some event within the brain as “the end.”

    X is watching TV, like on 9/11/01. Suddenly a picture appears of a plane flying into a building. The plane smashes into the building, and the building crumbles into flame: X observes all that (or say a few seconds later). The beginning of the causal chain of the WTC's attacks was quite precise: when the plane strikes the building with sufficient inertial force to cause the structure to collapse. While we might play along with a Kant (or Hume) and agree that our perception of the event does not equal the "ding-an-sich" (which is subject to forms of intuition such as space and time, etc. etc.), obviously an external event triggered the perception. Any "normal science" depends on assuming the objectivity of that sort of observational event (and so does the law, really--ah believe they call that proximate cause).

    The ultimate cause (the terrorists' plans, jihadist conspiracy, revenge, etc.) may not be immediately detected, but that's not the issue. Had the terrorists missed the WTC, there would have been a few reports, perhaps, but it would not have mattered too much. The skeptical doubts (and Popper's point really quite Humean--not particularly religious) may apply to origination, if not to history itself, but the immediate "proximate cause" obviously can be observed, and pin-pointed.

    We might agree there is a specifically human type of thinking that organizes the perceived event--understanding, consciousness, conception, etc. but one could hardly doubt the event (the crime really) starts with something happening in the external world.

    For that matter, any theological reading of atrocities such as 9-11 would imply that G*d himself was aware of it and allowed it to occur, and most theologians would probably not care to comment on that; and I doubt even Aristotle would say that a 9-11 was part of some divine plan......

    """"(In the case at hand, there is nothing in the bare empirical facts that determines that it is such-and-such brain processes, rather than the image on the retina, or rather than some different event altogether, that counts as the terminus of the relevant causal chain.) Such identifications are interest-relative and thus non-objective – or at any rate they are, I would add, if we assume a “mechanistic” conception of the natural world.""""

    Again one might grant that the scientists are not reproducing the actual sensation or experience of someone perceiving something (say of watching 9-11 on TV), but it's far more likely than not that a relation holds between what's produced in the brain, and what was perceived. Other studies have established the visual aspects of thinking (images taken from cortical scans of monkeys, etc). MRIs , brain scans may not at this stage show what Karpov does when he's working out some chess combination--that's does not preclude the possibility that they will in 10 or 20 years.

  4. J,

    The argument that you are trying to resist claims that even your initial description of events (e.g., 'the plane strikes the building with sufficient inertial force...,' 'a picture appears,' etc.) presupposes that you can identify the causally relevant events in question, but goes on to insist that there are no objective criteria for picking out some one event as the cause and some other as the effect. By 'objective criteria,' the argument understands criteria that do not depend on the interests of the person (in this case, you) picking out and identifying some events as causes and others as effects.

    So simply identifying some causes and effects doesn't get you anywhere, since the argument you're trying to refute presupposes that you can do that.

    The argument is not presenting Kantian worries about things-in-themselves, so your references to that miss the point. The argument also doesn't deny that science and law presuppose the objectivity of causation, and the fact that they do so doesn't do a thing to undermine the argument. For perhaps the sciences and law should be understood as pragmatists and other varieties of anti-realist understand them, as interest-relative constructs and not as identifying objective structures of causality, responsibility, or whatever. That's where Putnam takes the argument. He'd be unimpressed if you merely pointed out to him that we talk about causes and effects as though they were objective features of the world.

    Your attempt to dodge the problem by appealing to the 'proximate' rather than the 'ultimate' cause won't help you either. For the problem remains in any case that you pick out two events of a sequence, and identify one as the cause and the other as the effect. The Popper-Putnam argument challenges you to show that there is something about the way the world is (and not the way that the interests of observers pick out the events) that makes the one event properly 'the beginning' and the other one 'the end.' The fact that the event that causes the event that is its effect was also the effect of some other cause isn't supposed to be the problem. The question remains, rather, why should the plane smashing into the building be identified as the beginning of a discrete series of events that terminates in Jimbo Smith's observing via television the plane smashing into the building? Why shouldn't we pick out, or at least include, a whole bunch of other stuff as 'the cause' or 'the beginning' of the causal chain? The fact that the plane hitting the building was a necessary condition of Jimbo Smith seeing it on television doesn't really help you -- there seem to be lots of other necessary conditions, too, but the only people who pick them out as causes are desperate philosophers.

    So, if you want to answer the Popper-Putnam argument, you need to show that there are features of the world that make one event the cause (the 'beginning') and the other the effect ('the end') independently of the interests of anyone describing the events. You haven't even tried to do that, so you haven't even begun to answer the argument.

    You seem pissed off that Edward is a philosopher who is also 'religious' and thinks that his philosophical views are deeply consistent with his 'religious' beliefs. But insofar as you're resisting this particular argument, you aren't resisting religious belief at all. The two most famous defenders of the argument are Popper, who had no interest in religion, and Putnam, who, practicing Jew though he is, emphatically does not believe that his philosophical views can serve as anything remotely resembling a foundation for his religious views. Furthermore, plenty of lesser philosophers follow these two, and they take the argument as a reason to reject, variously, 1) realism, whether quite generally or scientific realism in particular; 2) causal theories of the mind, of any kind. Ed is different, it's true, because his use of the argument is to show that causal theories of the mental don't work unless you abandon the distinctly modern conception of causation in favor of an Aristotelian analysis. It's also true that he thinks his Aristotelianism is essential in defending the rationality of his religious views. But there's no more sense in resisting a particular argument because it plays a role in one person's defense of the rationality of his religious views than there is in resisting, say, Darwinism because the Nazis appealed to it to justify their racial theories (and no, I don't think that Catholicism and Nazism are anything remotely alike, by the way). The point is: argue with what you actually oppose, not with some other thing associated with what you actually oppose.

    J, your responses here repeatedly show no signs of actually engaging carefully with what you read. Please prove me wrong and actually address the argument instead of spouting off a bunch of non sequiturs and assuring us that processes in the brain are related to mental processes (nobody here or anywhere else has denied this, so get over it).

  5. Also, your comments about the 9/11 attacks and the problem of evil are just asinine. If anything, theologians and philosophers of religion have given too much attention to the problem of evil and taken it too seriously. Presumably you've missed the boat because you assumed when you read some selections from Hume's Dialogues as a sophomore that all the theists left in the world were just dumb, naive bastards who either hadn't read Hume or just dismissed him as immoral? I'd recommend some reading on the subject for you, except that you've proven to us by now that you only read philosophy at the WikiPedia and Short Introduction levels.

    Get real, dude.

  6. As I said, the sequence of the "9-11 crime" starts when the plane hits the building, and not until that point. So, yes, there's a point in time when the actual crime starts. That's not merely arbitrary.

    While induction, and natural science is not formal logic (a rather trivial point, which empiricists from the time of Hobbes have pointed out)
    most useful knowledge--like physics-- (yes, let's play pragmatist if you want) depends on observation, and a type of inductive method: for that matter so did the empiricism of Aristotle (who is hardly consistent on some metaphysical realism, if his texts are even to be held as accurate at all).

    As I said, the events leading up to the crime are only relevant because of the actual crime--had they missed the building, it wouldn't have been a big deal. It's not merely Jimbo Smith: it's a crowd of Jimbo Smiths, and departments of physics with Dr. Smiths examining the entire situation--all mostly in agreement with the applicability of Newtonian causality--and the objectivity of phenomena--in regards to macro events like a plane smashing into a building. They determined that the force of impact (impact itself sets out a rather specific point of time) was sufficient to knock down the building.

    That one cannot deductively establish causality, or even knowledge of the external world means little, except perhaps about the limits of deduction. Hume himself vented about that did he not, and then more or less still says Newtonian physics holds (as it does, except at subatomic levels, or near the speed of light), and that phenomena is regular more or less. That's what experimentalists had said for years: they were against the rigid orthodoxy of Aristotle. For that matter, one can easily turn the same skeptic-lite arguments against Aristotle, or any "realists": prove the supposed a priori nature of Aristotelian categories holds, or even of logic, mathematics itself.

  7. You're the naif here, if not outright vichy machiavellian and liar.

    But we await your proof of a prioricity!

  8. J,

    Just so you know, philosophy is about arguments, not assertions.

    Let me know when you come up with some.

  9. Ednonymous, you're the one making the rather outrageous and unscientific claim that we do not have sure knowledge of an external world, and that causality is all mind-made and subjective, denying a even something like "proximate cause": in effect even denying Hume's points about the regularity of nature (many (including Popper, probably) have mistaken Hume's points on causality for ultra-skepticism, when in fact it really concerns the difference between the inductive/probabilistic claims of natural science, vs, the axiomatic knowledge of logic and math).

    And you make the typical scholastic mistake (or is it subtle manipulation) that all arguments are deductive, when in fact even philosophical tradition distinguished between analytic/deductive argument (ie syllogistic ) and synthetic/inductive/probabilistic reasoning. For that matter, per Quine (not far from Hume, in many ways), analytical a priori itself has been called into question. So I think that would apply even to St. Aristotle's categories, but leave it to the theological

  10. There's something I'm still missing here. It seems like the neuroscientists can still detect which parts of the brain are correlated with immaterial abstractions. For example, some set of neurons fires when presented with a picture of a cow, and a different, non-disjoint set when presented with another cow. Then perhaps the intersection of these sets of neurons contains a representation of the concept of "cow" independent of a concrete cow image.

    Or if the concept of "cow" isn't enough to engage the intellect, what about the concept of "two". If someone is shown a sequence of images each with two objects, there is some common set of neurons that fires representing the concept of "two". Likewise, when the person performs some reasoning task involving the number two, the scientists might detect this same set of neurons firing. So I'm missing how some intellectual activities can't be grounded in brain activity.

    1. @S Jilcott,

      I know you posted this question 9 years ago, but anyway I thought I'd offer my two cents on the chance that someone else might find it useful.

      I think of this work that's being done on studying brain patterns as similar to studying a book in a language one doesn't speak. The story is written in a book. Anyone reading the story needs to look at the book, observe the ink on the pages. If you rip pages out of the book, the story will have parts missing. When you listen to someone reading the book, you might detect patterns - "ah, whenever you hear 'shtaim' you see the characters 'שְׁנַיִם'". There's a real and important relationship between the story, the ink and the paper. But it's not the case that the story IS the ink and the paper, and that mastering literature is equivalent to becoming an ink and paper expert.

      The brain is definitely the organ that is chiefly involved in thought (there's some recent studies hinting that we might think with our whole bodies). But the brain is not the whole story.

      Hope this helps