Craniopagus twins revisited: A response to Professor Egnor

Professor Michael Egnor has kindly responded to my post, The craniopagus twins from British Columbia: A test case for Thomistic dualism (TSZ, November 25, 2017), in a new post, titled, The Craniopagus Twins and Thomistic Dualism (ENV, December 10, 2017). In my earlier post, I had argued that “the twins’ ability to share thoughts without speaking weakens the case for Thomistic dualism, and lends support to a subtle variety of materialism which incorporates top-down causation.” In his response, Professor Michael Egnor gets to the heart of our disagreement and explains why he does not think that the experiment I proposed would serve to test whether dualism or materialism is true. Egnor proposes another test of his own, relating to mathematical abilities. In this post, I’d like to explain why I object to Professor Egnor’s test, before putting forward another one, very similar to it, which I believe could experimentally resolve whether dualism or materialism is true. Finally, I offer a few reflections on the philosophical argument which, Egnor contends, makes materialism logically untenable.

Do the Hogan twins share thoughts or just images?

In his latest article, Professor Egnor contests my claim that the Hogan twins are capable of sharing thoughts (“We talk in our heads” is how the twins describe it). Instead, he thinks, what the twins are sharing is probably mental images. Egnor also maintains that because the girls are twins who spend all their time together, it is likely that their thoughts are very much alike, which means that when they share the same image, they will both (individually) think the same thought, in parallel:

Where Torley disagrees with my view that the twins’ mental abilities are consistent with Thomistic dualism is on their ability to share thoughts. I assert that what they share are images, which are material mental things on the Thomistic view, but that they do not share abstract thought, which is immaterial. (By “images” I mean reconstruction of sensations — visual, auditory, tactile, etc. — in the absence of the object originally sensed.)…

It is clear that the Hogan twins share some thoughts — they giggle at private thoughts that they seem to share. Torley believes that these private thoughts entail some immaterial content. I believe they do not. I believe that the twins share images and perceptions, and that their reaction to the images that they share (giggling) is a manifestation that they both quite separately find the images funny.

In my view, the twins don’t share the intellectual immaterial thoughts. They do share some imaginary material thoughts (sensible species), from which they (at times) each individually extract similar immaterial thoughts (intelligible species). It is only the material sensible species that they share by virtue of their brain connection…

“Talking in their heads” can mean many things, and may just refer to shared perceptions from which they independently derive similar propositions. They may arrive at similar propositions from their shared image, in the same way that two different people may look at the same object and draw similar conclusions from it…

Personally, I think the girls’ description of how they communicate mentally without speaking aloud (“We talk in our heads”) is not at all what one would expect them to say, if they only shared mental images with one another. Professor Egnor evidently thinks differently. Fair enough. But as Huckleberry Finn famously put it, “RECKONING don’t settle nothing. You can reckon till the cows come home, but that don’t fetch you to no decision.” (Tom Sawyer Abroad, by Mark Twain, chapter 9.) What we need is an experiment.

Why Professor Egnor objects to my proposed experiment for testing dualism vs. materialism

In my earlier post, I proposed an experiment: allow each girl to (a) silently choose one statement from a list of six simple sentences containing abstract concepts, (b) decide whether she agreed or disagreed with the statement, and (c) mentally formulate an argument as to why she agreed or disagreed. If each girl could report on the other girl’s choice, agreement or disagreement, and her reasons, without the other girl telling her anything, then that, I argued, would surely show that the girls can share propositional thoughts, and not merely images. Professor Egnor is unconvinced. All it would show, he says, is that the girls think alike:

…[E]ven if they don’t share intelligible species, which is the Thomist view, they may still share sensible species/images and may separately derive the same intelligible species from it. This is particularly likely because of the close relationship between the two girls. They may routinely and individually derive the same abstract thoughts from a sensory image, yet not actually share the same abstract thought. This kind of thing is quite common, for example, with married couples over many years, who both think of abstract things at about the same time (my wife and I do this all the time). Similar things happen with non-conjoined twins and even with close siblings, for whom the actual sharing of thoughts is not an issue.

Now, this would be a perfectly legitimate criticism if the girls consistently made similar choices in the test I have proposed. But what if each girl held different opinions on some of the statements, but was nevertheless able to report accurately on the reasons underlying her sibling’s view, even if she violently disagreed with it? Now that would be a significant finding. Nor could it be explained by saying that as twins, they’re used to arguing over certain issues that regularly arise between them, such as what to eat (interestingly, the girls have different tastes in food). For in the experiment I proposed, the six sentences were entirely novel, and unlikely to have been seen or discussed by the girls previously. So I still think that the test could discredit dualism in the event of a disagreement of opinion between the girls over some of the sentences.

Professor Egnor’s new test

To his great credit, Professor Egnor then proposes a test of his own. He argues that if the girls differ in their mathematical aptitude, that would support Thomistic dualism, but if their mathematical aptitudes never diverge significantly from one another, then that would bolster the case for materialism:

I suggest another approach to testing the girls… If the twins share both material and immaterial powers of the mind, they should share mathematical ability very closely. They should have the same aptitude and the same comprehension of mathematical concepts at every stage of their education. If they share material and immaterial thought, they should share mathematical aptitude, and do so identically.

If they share perceptions (images), but not abstraction (concepts), they would be expected to differ at times in their mathematical aptitude. For example, both girls may share the perception for the symbol for a square root, but if they do not share immaterial thought, it is quite likely that one girl will understand what square roots mean before the other girl understands it… [I]f they do not share abstract thought, it is likely that in at least a few aspects of their mathematical education they will progress at different rates, because they have different comprehensions of the mathematical perceptions they share.

This can be tested rather easily. Thomistic dualism predicts that they will have at least occasional disparities in their understanding of mathematics, which would show up on standardized tests, school grades, etc. If they share intellect as well as perception, their scores and grades should be indistinguishable.

I would suggest that the mathematical test is more comprehensive and practical than the test suggested by Torley. If Thomists are right, the girls will diverge at times in their mathematical aptitude. If Thomists are wrong, and the girls share intellect and well as perception, they should not diverge at all.

I have to say that I regard this test as flawed, as it stands. My reason is very simple: the girls only share parts of their brains, not all of their brains. As I put it in my previous post, “the girls have two brains, not one, even if those brains are uniquely inter-linked.” In an article titled, Parts of the Brain Associated With Thinking Skills (Livestrong.com, August 14, 2017), neurologist Dr. Heidi Moawad writes:

Mathematical and analytical skills require a system of interaction between the temporal lobe, prefrontal region and parietal lobe, which is located near the back of the brain at the top of the head. Skills for algebraic mathematical tasks and calculations are generally concentrated in the left parietal lobe, while skills for geometric perception and manipulation of 3-dimensional figures are determined primarily by the right parietal lobe.

It is almost certain that the two girls’ brains differ in their relative proportions, in some of these areas, and in the number of neuronal inter-connections. That would likely give one girl a mathematical edge over the other, even if the materialistic hypothesis were correct.

An amended version of Professor Egnor’s test

Nevertheless, I think Professor Egnor is on the right track with his proposed test. So I’d like to propose a slight modification to it. Let’s say that one twin is having trouble grasping an abstract mathematical concept – say, the notion of congruence and how it applies to triangles, or the concept of a prime number, or for that matter, a negative number. If the more mathematically gifted twin were then able to correct her sister’s misunderstanding and enable her to grasp the new concept, without saying anything out loud, but simply by “talking in her head” to the other sister, then that would suffice to demonstrate that the two sisters can actually share abstract concepts, and not merely images.

I hope that Professor Egnor will accept my proposed modification to his test. I gather from his remarks on a recent podcast (Michael Egnor on What the Craniopagus Twins Tells Us about Mind and Brain, ID the Future, December 13, 2017) that he knows Dr. Douglas Cochrane, the neurosurgeon at B.C. Children’s Hospital who treats the Hogan twins. If that is the case, and if the girls’ mother is agreeable, then there is no reason why the test I have proposed could not go ahead. What say you, Dr. Egnor?

Why I don’t think philosophical arguments about the mind-body problem are logically compelling

Let’s suppose, for argument’s sake, that my modified version of Professor Egnor’s test was performed, and that it supported the hypothesis of materialism (the brain is capable of abstract thought) over that of Thomistic dualism (the brain stores images and sensory memories, but does not engage in abstract thought). Here’s an interesting question: would Professor Egnor change his mind? I suspect that he wouldn’t. It appears that he regards the philosophical arguments against materialism to be so powerful that no experimental finding to the contrary would cause him to alter his view. As he puts it:

I do point out, however, that in the Thomist view it is not merely empirically true that perception is material and intellection is immaterial. It is logically necessary for the intellect to be immaterial, because the intellect is that by which we contemplate universals, which by definition do not have particular existence and thus cannot be material.

If the twins were shown to share intellect as well as perception, it is not merely our theory of mind that would need revamping, but the logical and metaphysical basis for Western thought as well.

Now, I will readily acknowledge that there are some very powerful prima facie arguments in favor of dualism. Associate Professor Edward Feser has discussed some of these in a series of posts:

Some brief arguments for dualism, Part I
Some brief arguments for dualism, Part II
Some brief arguments for dualism, Part III
Some brief arguments for dualism, Part IV
Some brief arguments for dualism, Part V

But there is an ocean of difference between a highly persuasive argument and a compelling one: the former may (in theory) be mistaken, while the latter cannot. So it’s worth quoting what Dr. Feser himself has to say about the much-vaunted argument from universals:

Whatever one thinks of arguments like this, it is important to understand that (like the other arguments I’ve presented in this series) they are not the sort that might be undermined by the findings of neuroscience, or any other empirical science for that matter. They are not “soul of the gaps” arguments which purport to give a quasi-scientific explanation of some psychological phenomenon that we simply haven’t got enough empirical data to explain in a materialistic way. Rather, they purport to show that it is in principle impossible, conceptually impossible, for the intellect to be accounted for in a materialistic way. If such arguments work at all, they establish conclusively that the intellect could no more be identified with processes in the brain than two and two could make five. If they are mistaken, they would be mistaken in the way one might make a mistake in attempting to carry out a geometrical proof, and not by virtue of having failed to take account of this or that finding of brain research.

Reading between the lines, I get the sense that Dr. Feser himself isn’t 100 per cent sure that the arguments for dualism are both valid and sound. Why might that be?

(i) Universals are particularizable

Let’s look at Professor Egnor’s argument first:

1. By definition, universals do not have particular existence.
2. By definition, material things and processes have particular existence.
3. Therefore, necessarily, universals are not material.

The problem lies in the vague term “particular existence.” It is certainly true by definition that universals are not particular objects belonging to the group whose properties they generalize. The concept of a panda is not a particular panda; nor is the concept of a triangle a particular triangle. But it does not follow that these concepts do not possess particular existence of some sort or other.

How might this be so? Let’s take the common concept of a triangle: a closed two-dimensional figure having exactly three sides (and three angles). (Mathematicians will tell you that’s actually a Euclidean triangle, but let that pass.) I could represent this concept in code, if I wished: C23, where the first letter indicates whether the figure is open (O) or closed(C), the second character represents the number of dimensions (2) and the final character denotes the number of sides (3). Viewed in this way, the concept of a triangle does turn out to have particular existence, after all: each of the characters in the three-letter code has a particular value.

The same goes for the common definition of a giant panda: a large black-and-white herbivorous bearlike mammal. The panda is a mammal, and not a bird, reptile, amphibian or fish. It’s a member of the bear family (not the dog family), within the order Carnivora (animals whose teeth and claws make them specially adapted to meat-eating). Unlike other bears, it’s black-and-white in color. And most unusually, it’s a herbivore. Once again, the concept seems to be “particularizable,” to coin a term. The only vague predicate in the definition is “large,” but even here we can set particular limits by specifying a range: adults are 1.2 to 1.9 meters long, for instance. I see no reason in principle why the brain cannot store such information. I am not saying that it does, of course; only that it might.

(ii) The term “concept” is not a natural kind

Dr. Feser’s argument is somewhat more subtle (which is hardly surprising as he is, after all, an Associate Professor of Philosophy). Feser writes:

Consider that when you think about triangularity, as you might when proving a geometrical theorem, it is necessarily perfect triangularity that you are contemplating, not some mere approximation of it. Triangularity as your intellect grasps it is entirely determinate or exact… Of course, your mental image of a triangle might not be exact, but rather indeterminate and fuzzy… Any mental image of a triangle is going to have certain features, such as a particular color, that are no part of the concept of triangularity in general. A mental image is something private and subjective, while the concept of triangularity is objective and grasped by many minds at once.

Quite so; but all that proves is that the concept of a triangle is not a mental image. What it doesn’t prove is that the concept of a triangle is immaterial. But Feser is not done yet, for he continues:

Now the thought you are having about triangularity when you grasp it must be as determinate or exact as triangularity itself, otherwise it just wouldn’t be a thought about triangularity in the first place, but only a thought about some approximation of triangularity. Yet material things are never determinate or exact in this way... And in general, material symbols and representations are inherently always to some extent vague, ambiguous, or otherwise inexact, susceptible of various alternative interpretations. It follows, then, that any thought you might have about triangularity is not something material; in particular, it is not some process occurring in the brain. And what goes for triangularity goes for any thought that involves the grasp of a universal, since universals in general … are determinate and exact in a way material objects and processes cannot be.

The key premises in Feser’s argument appear to be as follows: (i) concepts are inherently determinate; (ii) our thoughts about these concepts are likewise inherently determinate; (iii) material objects and processes, on the other hand, are inherently indeterminate; therefore (iv) our thoughts are not material objects or processes.

Unfortunately, Dr. Feser does not provide us with anything like a general argument as to why he believes material things and processes are inherently ambiguous or capable of alternative interpretations. (He refers to the work of the philosopher James Ross, which is summarized here. Ross’s main argument is that the various instantiations of a mathematical concept – e.g. the concept of the square of a number – do not uniquely determine its content, as a finite number of instances cannot fix the rule: another interpretation is always possible. But what this proves is not that material processes are inherently ambiguous, but that the meaning of a mathematical concept can never be exhausted by its instances. Fine; but who said it could? And in the case of squaring, the instances aren’t even material, anyway; they’re numbers!)

Feser appears to believe that abstract objects (such as the concept of a triangle) are incapable of alternative interpretations, but again, he does not tell us why. Perhaps his thinking is that you either grasp them or you don’t. This is more promising; but the question we need to ask is: what makes them graspable? Is it their immateriality, as such? And if so, why? Feser does not tell us.

The anatomy of a dog

Finally, Feser neglects to mention the inconvenient fact that not all concepts are equally determinate. For instance, the biological concept of a dog [pictured above] (which is capable of hybridizing with a wolf or a fox) is much fuzzier than the mathematical concept of a triangle, the chemical concept of gold (element number 79) or for that matter, the biochemical concept of DNA (which may contain non-canonical bases). And what about the geographical concept of a mountain (arbitrary cut-off point) or for that matter, the concept of “bald” (where does one draw the line)? What about the concept of love (which some people confuse with liking), or the concept of justice (which means different things to different people)? I could go on, but I won’t belabor the point.

The real problem here is that, as philosopher Edouard Machery puts it in a brilliantly argued 2004 essay, Concepts Are Not a Natural Kind. Indeed, Machery argues that we don’t even have a single concept of “dog”: we have several concepts. He concludes:

First, the notion of concept is ill-suited to formulate scientifically relevant generalizations about the mind. Psychologists should focus instead on other classes of mental representations, particularly prototypes, exemplars, and theories (and eventually others). In other words, the notion of concept does not carve the mind at its joints. Second, the controversy between the main psychological theories of concepts is deeply misguided. Concepts are neither prototypes, nor exemplars, nor theories. Some concepts are prototypes, some concepts are sets of exemplars, some concepts are theories. The theory view of concepts, the prototype view of concepts and the exemplar view of concepts are not inconsistent theories about our concepts: instead, they characterize the main features of three basic different kinds of representations. Finally, this position raises a provocative question: if the notion of concept is ill-suited for scientific purposes, do we need it at all? But this is certainly a topic for another day.

More recently, Machery has written a provocatively titled book, Doing Without Concepts, proposing that we jettison concepts altogether (see here for a critical review). This is a very extreme move, and in my opinion, an over-reaction, but Machery has at least performed the philosophical service of forcing us to re-examine our preconceptions about what the mind does and how it works. Philosophical arguments based on the nature of our mental concepts should never be used to over-rule the findings of science, because we can never be certain that we actually think in the way we assume we do.

I would like to close with a plea for an open mind. The philosophical tradition of dualism is a venerable one, which is supported by some ingenious philosophical arguments; but as far as I can tell, the case for dualism is far from airtight. That’s why experiments are so useful. They can, at least, help to eliminate bad hypotheses about the mind, even if they can never prove any particular hypothesis to be true.

In a recent podcast (Michael Egnor on What the Craniopagus Twins Tells Us about Mind and Brain, ID the Future, December 13, 2017), Professor Egnor cited the pioneering work of Wilder Penfield, Benjamin Libet and Roger Sperry, and concluded: “Any objective person looking at the science would have to come away with the viewpoint that dualism makes the most sense here.” Penfield and Libet were indeed both dualists; but Sperry was not. He was a monist, and a strong determinist at that, although he believed in a version of downward causation. His student, Michael Gazzaniga, is a materialist who maintains that determinism is compatible with a version of free will: brains are automatic, but people are free, as he puts it. The point I wish to make here is that neither the scientific data nor the philosophical arguments for or against dualism are compelling, right now. To take one instance: the split-brain work of Sperry and Gazzaniga seemed to disprove dualism, but more recent work by cognitive psychologist and physicist Yaïr Pinto points the other way: when you split the brain, you still end up with only one person. The moral of this story is that we need to keep digging and avoid a rush to judgement.

What do readers think?

85 thoughts on “Craniopagus twins revisited: A response to Professor Egnor

  1. Robert Byers: Ah. Yet thats not true. ether, etc, was not dismissed out of hand but defeated by investigion.
    the soul was never defeat in its existence but ruled away as a option based simply on a rejection of it as a option.

    It is rejected on the same basis as phlogiston and the ether.

    Take a look at the Campolo book “Why I left, Why I stayed”. Bart dropped his belief in an immaterial soul, after an accident he had that caused brain injury. From the effects of that injury, he could tell that what he had been crediting to the soul was due to the brain.

  2. Neil Rickert: I don’t see concepts as representations. I see them more as nodes in a perceptual network. Roughly speaking, concepts are what guides us in how we carve up the world.

    And here I was going to say that representations are what guides organisms in how they carve up the world, with concepts being a specific way of doing that.

    Perhaps I should not that I consider proprioception (roughly, self-perception) as an important kind of perception.

    As do I. I think the most primitive kind of ‘objectivity’ is the ability to compare perceptual changes that are a result of moving one’s body with perceptual changes that are not, and that’s not possible without proprioception.

    Maybe I should stop there, or we will finish up talking past one another.

    I think that we are quite close in one way and still far apart in another.

    We’re very close in our pragmatic theory of concepts, with two differences, one minor and one major.

    The minor difference is that I think it is important to use the concept of representations when explaining what’s going on at the neurocomputational level. That might be a semantic quibble because you and I mean quite different things by “representation”. (You don’t think that maps are representations, and I do, for example.)

    The major difference is that you think that concepts and theories should be assessed in terms of usefulness instead of in terms of truth. By contrast, I think that usefulness is strongly correlated with (but not identical with) adequacy: an animal representational system is more useful to the animal to the extent that it reliably tracks underlying real patterns that are relevant to the satisfaction of the animal’s needs and goals.

  3. Neil Rickert: It is rejected on the same basis as phlogiston and the ether.

    Take a look at the Campolo book “Why I left, Why I stayed”.Bart dropped his belief in an immaterial soul, after an accident he had that caused brain injury.From the effects of that injury, he could tell that what he had been crediting to the soul was due to the brain.

    he got the equation wrong.
    It was his memory that would be affected in a accident.(Actually I say the triggering mechanism for memory and not the memory itself)
    i don’t think our souls do remember things WHILE we have a material memory.

  4. Kantian Naturalist,

    Ok, for both your sakes, concepts are representations. Abstractions are representations. That doesn’t conflict with thinking of concepts as nodes in a network. Except: what the hell is a perceptual network? A network of perceived stuff? A network with concepts would be a conceptual network, not a perceptual one, even if applicable to something we perceive. The networks themselves are conceptual.

    Seems like you’re talking past each other because some need for clarifications everywhere.

    Anyway, was this conversation between Neil and you prompted by the incredibly imbecilic argument for dualism by Eggnog?

  5. Entropy,

    To me personally dualism doesn’t even make sense from biblical/Christian point of view though I do admit that many of those concepts are fairly new to me….
    Having been raised Catholic and abandoned that religion and its non biblical teachings, I have been researching the possibility of quantum consciousness/soul that requires fully functionality of human brain to experience awareness…

  6. Kantian Naturalist: an animal representational system is more useful to the animal to the extent that it reliably tracks underlying real patterns that are relevant to the satisfaction of the animal’s needs and goals.

    This is where we disagree.

    There are no such things as “underlying real patterns”. We do not find patterns in raw reality. We find them in our representations. In turn, our representations depend on our concepts. So what we see as patterns depends on our concepts.

    You want to start with patterns, and then get to concepts. But it is the other way around. We (or, really, the developing organisms) have to start with concepts. And initially, pragmatic judgment is the only way available for making decisions.

  7. Vince,

    I think you gave Eggnog too much credit. Isn’t he a lawyer? Either way, I doubt that he deserves to be called “professor.” Sophist might be more appropriate.

    I do point out, however, that in the Thomist view it is not merely empirically true that perception is material and intellection is immaterial.

    Empirically? I’d like to see that evidence. How was it determined that the intellect is immaterial empirically? Did they measure the spirituality of the intellect? What’s the equipment for measuring spirituality like? What an ass.

    It is logically necessary for the intellect to be immaterial,

    Here I was preparing for some deeply insightful stuff (nah, I wasn’t).

    because the intellect is that by which we contemplate universals, which by definition do not have particular existence and thus cannot be material.

    The level of stupidity condensed in this pair of sentences is beyond belief. Ah! That means that sentences are immaterial! How else could that amount of imbecility be concentrated in just two of them!

    When we “contemplate” universals, we’re not really “contemplating” them, we’re just imagining them. Nobody really sees the whole enchilada in their minds, we use a single concept to mean a lot of the same kind of shit. For example, the concept of “universal” doesn’t use a lot of space, but can refer to anything and everything. If I refer to the concept of a human, the space for the concept is finite, and I really don’t have every human who has ever existed, or who’s ever going to exist, in my mind. Each concept in itself, whether referring to a “universal” or to a “particular” is finite and “particular.”

    Eggnog is mistaking concepts and referents. Concepts about universals are not the same as the universals themselves. Having a concept about something that might be imagined as “universal” doesn’t mean we have some limitless thing in our minds. We only hold the concept, not the universe, in our minds. The “method” for such “contemplation” is nothing but induction-then-extrapolation.

    Jumping from “I hold a concepts about things that could not possible exist in a particular form, therefore it’s all magical crap” is an imbecilic non sequitur of unsurmountable magnitude. Therefore immaterial (muahahaaaaaaahaaaaahaaaaaa!).

  8. Neil Rickert: You want to start with patterns, and then get to concepts. But it is the other way around. We (or, really, the developing organisms) have to start with concepts. And initially, pragmatic judgment is the only way available for making decisions.

    I agree with the first part (which I didn’t quote), we go from perceived shit to concepts and we find the patterns in our conceptual shit. But we cannot “start” with concepts. Concepts cannot be formed without perceived shit to build upon.

    Percepts are first, then concepts, then we work with the concepts.

    The mistaking our conceptual frameworks and descriptions for their referents is one of the many problems with “fine-tuning,” by the way. Imagining that because our descriptions require very precise “constants” therefore the universe is finely-tuned is to mistake our descriptions for the universe for the universe itself. It’s the other way around, the constants in our equations are finely-tuned in order to represent our observations about the universe. If we change those constants, the equations no longer describe our observations. Oh, how surprising!

    Hey, if I change the value of pi in the equation of a circle the equation doesn’t describe a circle any more! Wow! Then the circle was finely-tuned to have pi!

    Yes, it’s that stupid, only we don’t notice because people have gotten used to the idea that some equations “govern” the universe, when all they do is describe our observations about it.

  9. Entropy: Concepts cannot be formed without perceived shit to build upon.

    That’s backwards. Without concept, perception is impossible.

    There’s a dynamic interaction involved. Start with concepts (non-linguistic non-conscious concepts) so as to make perception possible. And then adjust and improve those concepts so as to improve perception.

  10. Entropy,

    Egnor is a neurosurgeon and professor of pediatrics, for what it’s worth. That’s not to say that his credentials extend to speaking authoritatively about the nature of concepts.

    As I see it, the real problem with Egnor’s Thomism is the following line of thought:

    1. There is a real difference between universals and particulars.
    2. Particulars are material.
    3. Therefore, universals are immaterial.

    The problem is this argument conflates three quite different distinctions: the universal/particular distinction, the concept/object distinction, and the immaterial/material distinction. For it is only if we conflate all three of these do we get the conclusion that since universals are not particulars, and all particulars are objects, then universals cannot be objects, and since they are not objects, then then must be “immaterial”.

    It is perfectly true that we distinguish between the sense of a concept and its application. When we classify an object as satisfying a concept (“that’s a lion!”), we index the concept to some spatio-temporal particular. That’s different from reflecting on the sense of the concept (“lionhood”), or inquiring into the place of the concept lion within our conceptual system.

    But nothing in that line of thought tells us that concepts cannot themselves be material objects of some sort or other.

    The relationship between concepts and objects could very well be a relationship between two different kinds of material dynamic processes: those that are endogenous to the organism (its neurocomputational processes) and those that are exogenous to the organism (the processes in its environment).

    To close the door to this view (which is, for what it’s worth, the consensus view among cognitive scientists and naturalistic philosophers of mind), one would have to argue that since we are not immediately aware of concepts as being neurocomputational processes, then they cannot actually be neurocomputational processes.

    The problem here is that this response invites the following naturalistic reply: just because we’re not immediately aware of physical objects as being temporally stable sets of quantum fields, it doesn’t follow that physical objects are not actually temporally stable sets of quantum fields.

    What the contemporary Thomist needs is a Cartesian move: that introspection is epistemically reliable in ways that perception is not.

    The contemporary Thomist needs this because she needs to be able to say that just because our sense-perception doesn’t tell us what physical objects really are, it doesn’t follow that introspection cannot tell us what concepts really are. And that works only if introspection reveals to us what concepts really are, even though sense-perception doesn’t tell us what objects really are.

    It is worth noticing that Aquinas himself did not need this, because his physics is Aristotelian physics, which is to say, it is nothing over and above a description of how we experience physical objects. To use a term of art, Aristotle’s physics is a phenomenology of nature: he is describing how we experience movement and change. But while there is real value in a phenomenology of nature in aesthetics and ethics, there’s also a real conflict between an Aristotelian phenomenology of nature and what we learn from the experimental, quantitative sciences, i.e. “the scientific worldview”.

    So what the Thomist needs, to salvage her views about the mind in the wake of the Scientific Revolution, is to become a Cartesian: she needs to maintain that while the scientific worldview does give us new understanding about objects, it does not challenge our ordinary assumptions about concepts. And this in turn requires her to maintain that introspection is epistemically reliable in a way that perception is not.

    Thus, while the Thomist does not have to endorse Descartes’ version of mind/body dualism, wherein the mind and body are different “substances”, she does have to endorse the Cartesian assumption that introspection is a reliable source of knowledge about what concepts really are even though perception is not a reliable source of knowledge about what objects really are.

    Without that assumption, the door is wide open for the naturalistic philosopher of mind to say that experimental sciences can call introspection into question just as they call perception into question.

  11. Entropy,

    No, I’ve been ignoring Egnor. And I don’t find any version of dualism viable. Metaphysical naturalism is the only game in town. The difficulty is to figure out a version of it that works.

    My argument with Neil is a long-standing discussion that he and I have been having for years. We’re both strongly influenced by Wittgenstein on language and Gibson on perception, so to some extent we’re haggling over the details. But that’s where it’s possible to get down to the fine-print of philosophy.

  12. Neil Rickert: That’s backwards. Without concept, perception is impossible.

    No it isn’t. All that’s needed for perception is the senses and the machinery that links what the senses capture to the brain processes. It seems like you’re mistaking perception for identification. Identification is where the processes of the brain called “mind” get involved. But perception can be simpler than with our human example. Bacteria perceive without any concepts involved.

    Neil Rickert: There’s a dynamic interaction involved.

    With this I agree, but how would we form a concept of a human without ever perceiving a human?

    Neil Rickert: Start with concepts (non-linguistic non-conscious concepts) so as to make perception possible.

    Disagreed again. Perception is possible because of the senses.

    Neil Rickert: And then adjust and improve those concepts so as to improve perception.

    No amount of thinking about it have ever made my sight any better.

  13. Entropy,

    I think it’s useful to distinguish between perception and sensation. Sensing is (or can be) passive or (as Kant would say) “receptive”. That’s different from perceiving — especially in the kinds of cases that Neil is interested in, where we perceive objects.

    He wants to say (I think) that we cannot perceive an object without having a concept of that object. I think that’s right, to some extent: perceiving an object as being an instance of a kind (e.g. being able to see a lion as being a lion) requires having the concept of a lion. Without the concept, the mind would have no way of organizing the sensory influx in the right way.

    This is, by the way, perfectly compatible with being a metaphysical naturalist and thinking that concepts are neurocomputational states.

    In the predictive processing model of cognition (see here and then here), brains are generating predictions about what sensory stimuli to expect (both exteroceptive and interoceptive) and then revising those predictions based on prediction errors: the spike trains initiated at sensory receptors feed into sub-models that convey estimates of how far off the predictions were.

    Thus, one needs a representation of “lion” in order to have a model that expects there to be lions in ones environment, but the function of sensory receptors is to convey whether those expectations are satisfied or frustrated. This can happen at varying levels of cortical hierarchy: if you’re turning a street corner and see a lion, you’ll be surprised or terrified — but you’ll still see it as a lion, if the concept of “lion” is in your model of what the world is like.

  14. Entropy: All that’s needed for perception is the senses and the machinery that links what the senses capture to the brain processes.

    With just the senses, about all you can get is:

    Ooh, something was stimulated. Ooh, something else was stimulated.

    That’s not enough.

    No amount of thinking about it have ever made my sight any better.

    Your sight had already been honed into shape, well before you learned to think.

  15. Kantian Naturalist:
    Entropy,
    I think it’s useful to distinguish between perception and sensation. Sensing is (or can be) passive or (as Kant would say) “receptive”. That’s different from perceiving — especially in the kinds of cases that Neil is interested in, where we perceive objects.

    Then we’re having a problem with our definitions. In my words above, perception is the same as sensation in your explanation, while I used “identification,” probably to mean what you called “perception.” Our definitions seem to be “one times removed.”

    Kantian Naturalist: He wants to say (I think) that we cannot perceive an object without having a concept of that object. I think that’s right, to some extent: perceiving an object as being an instance of a kind (e.g. being able to see a lion as being a lion) requires having the concept of a lion.

    Which is why I prefer to say “identify,” because the action is not really one of perceiving, but one of identifying the lion as a member of the group we have conceptualized as “lion.”

    Kantian Naturalist: Without the concept, the mind would have no way of organizing the sensory influx in the right way.

    Yep, but we cannot form the concept of a lion without ever sensing one. In my wording, identifying a lion as a lion requires the prior concept, but the concept could not be formed without having experienced (perceived) a lion before.

    Kantian Naturalist: This is, by the way, perfectly compatible with being a metaphysical naturalist and thinking that concepts are neurocomputational states.

    I agree. As I said, I think that most of the problems with your conversations is that you seem to be using different definitions, and, often, with little clarity about them.

  16. Entropy: Which is why I prefer to say “identify,” because the action is not really one of perceiving, but one of identifying the lion as a member of the group we have conceptualized as “lion.”

    Perception couldn’t work the way that you seem to think that it does.

  17. Neil Rickert: Perception couldn’t work the way that you seem to think that it does.

    It would help if you explained what you mean here.

    If perception, as I define it, is what the senses do, then it works exactly as I explained. In my wording, identification would not work without perception. Identification requires the concept to be there (which looks like what you’re saying, but who the hell knows). But perception requires the objects and the senses.

    Concepts are representations. To represent lions we need the experience of lions. Identifying other lions requires the concept, but the concept itself could not be formed without the prior experience of lions.

    In your view, where do concepts come from?

  18. Entropy: If perception, as I define it, is what the senses do, then it works exactly as I explained. In my wording, identification would not work without perception. Identification requires the concept to be there (which looks like what you’re saying, but who the hell knows). But perception requires the objects and the senses.

    But what do you mean by “the senses”?

    For most people, “the senses” means some sort of unexplained magic that goes on, so that it all works. I don’t find the expression “the senses” to be at all useful.

  19. If “the senses” means “sensory receptors”, then “the senses” means such things as the rods and cone cells in the retina, the stereocilia in the cochlea, and so on.

    But if “the senses” means “modes of sensory consciousness” — what we are aware of as seen, heard, smelled, etc. — then there’s going to be far more cognitive processing than just the activation of sensory receptors.

  20. Neil Rickert,

    Holy crap. Sure Neil, I meant magical shit.

    By the way, all the context where I talked about the senses, it was there for no reason. I’m glad you noticed and ignored the whole thing.

  21. I tend to take Neil’s side in discussions of perception. I don’t think ordinary language is helpful. And “scientific” language is in its infancy. Kind of like alchemy. A transition from animism to science.

  22. Kantian Naturalist:
    If “the senses” means “sensory receptors”, then “the senses” means such things as the rods and cone cells in the retina, the stereocilia in the cochlea, and so on.

    But if “the senses” means “modes of sensory consciousness” — what we are aware of as seen, heard, smelled, etc. — then there’s going to be far more cognitive processing than just the activation of sensory receptors.

    This doesn’t fit at all with all the facts that have been documented by many experiments on patients under general anesthesia, where patients are totoally unconscious; they don’t dream, don’t feel anything, don’t remember anything…And yet, the EEG tests indicate normal brain activities…

    What’s interesting is that anesthetic gasses disable the functions in microtubles of neurons, where it was long suspected conscious experiences are “processed”…

  23. J-Mac: This doesn’t fit at all with all the facts that have been documented by many experiments on patients under general anesthesia, where patients are totoally unconscious; they don’t dream, don’t feel anything, don’t remember anything…And yet, the EEG tests indicate normal brain activities…

    No they don’t.

    To be sure, they’re thinking that the EEGs probably aren’t reflecting the more crucial aspects, but the EEGs still are affected.

    Glen Davidson

  24. GlenDavidson: No they don’t.

    To be sure, they’re thinking that the EEGs probably aren’t reflecting the more crucial aspects, but the EEGs still are affected.

    Glen Davidson

    This is the the introduction to the article you linked:

    “A large-scale study published in the New England Journal of Medicine has sparked a flurry of controversy among anesthesiologists. According to the findings, a commonly used device designed to prevent anesthesia awareness–the rare event when a patient is actually conscious during surgery–was largely ineffective.”

    Anesthesia awareness-the rare event …

    As the article goes on, usually in anesthesia awareness rare events, not enough anesthetic drugs where applied or they where wearing off faster than in most patients…
    Different drugs and drug amounts work differently on different patients…

  25. Entropy: It would help if you explained what you mean here.

    If perception, as I define it, is what the senses do, then it works exactly as I explained. In my wording, identification would not work without perception. Identification requires the concept to be there (which looks like what you’re saying, but who the hell knows). But perception requires the objects and the senses.

    Concepts are representations. To represent lions we need the experience of lions. Identifying other lions requires the concept, but the concept itself could not be formed without the prior experience of lions.

    In your view, where do concepts come from?

    Yes we must fIRST see lions and then place further sightings in the lion perception.
    its just a memory issue.
    Why not? Why make it hard!
    The issue in all this is its not understood one(soul0 is always reading the memory screen. so sticking anything to the memory is the only mechanism.
    You don’t need any other concepts or words.
    The memory is not a sidecar to the brain processing senses input.
    It is the only organ at work.
    Dreaming shows this too. Ones dreams are asw vivid as when awake because there is no difference. in both case,sleep/awake, the same mechanism is going on. simple soul reading of the memory screen.

  26. petrushka,

    Of course ordinary language is not useful. That’s my point. In philosophy, commonly, perception means the part where the senses, as in not-the-magical-shit-but-the-hearing-seeing-etc, do their work. The “data collection.” Whereas identification is what we do with what the senses have given us.

    Neil and Kantian have been discussing using nebulous terms, which leads to talking past each other. I think they don’t disagree too much. I don’t disagree too much with them either. It’s just that the language is not very clear, and thus the levels they’re describing don’t match each other, a few times not even within a sentence.

    Anyway, I’m out of the discussion. Seems like I brought more chaos than understanding. So I apologize for the interruption.

  27. Entropy,

    For what it’s worth, I appreciate your contributions to our discussions. Just because I disagree with you doesn’t mean I don’t value your comments.

    I think that one major source of confusions in philosophy of mind turns on the conflation of person-level concepts and subperson-level concepts. It’s one thing to talk about what animals and persons do (as sensing-imagining-knowing-willing systems) and quite another to talk about what brains are doing (as information-processing organs). It’s roughly the difference between what we’re doing when we do phenomenology and what we’re doing when we’re doing cognitive neuroscience.

    The debate between myself and Neil hinges on whether pragmatic coping can be cleaved apart from veridicality.

    Neil wants to say that cognitive systems are geared towards pragmatic coping and therefore not veridicality. And he rejects my urge to talk about representations because he thinks that representations have to be veridical to count as representations. (This is why he thinks photographs are representations but maps are not.)

    I don’t insist on veridicality as a criterion for representations, and I’m quite happy to say both that maps are representations and also that much of animal & human cognition involves map-like representations. My interest in predictive processing lies in its promise as a theory of what map-like representations are like.

  28. Kantian Naturalist: Neil wants to say that cognitive systems are geared towards pragmatic coping and therefore not veridicality.

    Not quite right.

    Rather, I see veridicality as a pragmatic invention.

    And he rejects my urge to talk about representations because he thinks that representations have to be veridical to count as representations. (This is why he thinks photographs are representations but maps are not.)

    I have no idea where that comes from.

    Well, okay, I suppose it is because of the contrast I drew between a road map and an aerial photograph. But the difference is in how we use them, rather than in what they are.

  29. vjtorley: If you’re going to speak of souls, then the new embryo has a new soul of its own.

    It’s likely science will advance to the point where creating a human embryo is trivial. Is there an inexhaustible supply of souls available?

  30. Neil Rickert: I see veridicality as a pragmatic invention.

    Whereas I would suggest the whole idea of “veridicality” is an unattainable existentialist essentialist* invention. It’s Plato’s fault, not the pragmatists. 🙂

    ETA *Oops!

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