Friday, September 17, 2010

"Biologico-Teleological Considerations as to Space" (Ernst Mach)

Just for a little historical perspective on our topic, I am appending an excerpt from Ernst Mach's book, Analysis of Sensations (1897), the beginning of Chapter 9 entitled "Biologico-Teleological Considerations as to Space":

We have already repeatedly had occasion to notice how very different the system of our space-sensations--our physiological space, if we may use the expression--is from geometrical (by which is here meant Euclidean) space. This is true, not only as regards visual space, but also as regards the blind man's tactual space in comparison with geometrical space. Geometrical space is of the same nature everywhere and in all directions, it is unlimited and (in Riemann's sense) infinite. Visual space is bounded and finite, and, what is more, its extension is different in different directions, as a glance at the flattened "vault of heaven" teaches us. Bodies shrink when they are removed to a distance; when they are brought near they are englarged: in these features visual space resembles many constructions of the metageometricians rather than Euclidean space. The difference between "above" and "below," between "before" and "behind," and also, strictly speaking, between "right and left," is common to tactual space and visual space. In geometrical space there are no such
differences. (p. 181f)

By "physiological space," presumably Mach means that which is customarily called "perceptual space" (or "phenomenal space") today, including but not being confined to visual sensations. His use of the term "visual space" to denote just the visual component of perceptual space supports my previous contention that this term has long been used for the space of visual sensations (at least in science, if not philosophy). Rather than relating some of the characteristics of VS to projective geometry, Mach relates them to metageometry (i.e., what today is called non-Euclidean geometry). Other characteristics that he notes (e.g., left and right) as departing from Euclidean space are now considered to be topological properties of space.

In a previous chapter Mach notes that "optical space" [a term he uses synonymously with "visual space"] represents geometrical space (Euclid's space) in a sort of relievo-perspective." (p. 169) There is a wealth of other observations and points about visual/perceptual space in Mach's book, and I highly recommend it for that reason, and as ostensibly being the first to propose that VS is non-Euclidean, though not apparently on the basis of curvature, but on the basis of it being like a perspective projection.


  1. Ludwig, Jonathan Harrison's celebrated "brain-in-a-vat" has a phenomenal space just like ours, but has do access to physical space. The afferent input to his brain is supplied entirely by Professor Smythson's supercomputers that provide the same input that Ludwig's brain would have had from his sense-organs had they not been removed by Professor Smythson. This suggests that phenomenal space and physical are ontologically different spaces (as Broad, Price, Russell, Carr and I have suggested). More details on Ludwig will be supplied if anyone wishes them.
    Two other authors with something interesting to say:
    1. W.C. Gogel ("A theory of phenomenal geometry and its applications" Perception and Psychophysics, 48, 105-123, 1990) says
    "An observer, upon viewing a three-dimensional visual scene, acquires an internal spatial representation...This internal representation, usually supported by sensory information, is an instance of phenomenal space. The geometrical description of this phenomenal space will be called phenomenal geometry."
    2. T, Indow ("A critical review of Luneberg's model with regard to the global structure of visual space." Psychological Reviews, 98, 430-453, 1991) says that visual space is the final product of a long series of processes from retina to brain, and phenomenologically it is articulated nto individual objects, backgrounds and Self...VS is bounded in all directions. We never perceive anything at an infinite distance." He adds that The Self (0) and VS are separated by "vacant space" and there is a correspondence between the structures of VS and physical space.

    Note the "internal spatial representation", "final product" and "vacant space" above.

  2. I think we should distinguish between geometries and spaces. Today geometers would say that a space may contain different geometries, but that the space itself has its own geometry. In Mach's day that distinction was not made. Whereas the four-dimensional space-time continuum of physics may contain many geometries, Einstein believed that the geometry of space-time itself was curved due to gravitation, i.e., gravity curves space-time: A ray of light moving in a straight line would continue to infinity in a straight line were it not for gravity curving the fabric of space-time itself and thus bending light.

    An identity theorist could counter that Ludwig's "phenomenal space" is a subset of the physical space between his ears, so in spite of the diabolical Dr. Smythson's experimental set up, the fact that Ludwig still has a phenomenal space might reflect the continued functioning of his CNS, and does not demand positing another another space(-time) system.

    Walt Gogel is not talking about VS, but of cognitive representations of it. Indow's account really offers nothing new. I would argue that VS contracts drastically towards the observer when we close our eyes. Just compare VS with eyes open vs. eyes closed to "see" the difference. The depth provided by stereopsis has a good deal to do with the impression of "vacant space" extending outward from the observer I should think.

  3. In James Culbertson's book "Consciousness: Arificial and Natural" he details an account he first proposed in his "Minds of Robots" (1963) that conscious perception requires certain special connections in space-time sequences, and shows what those are (so he thought at least; physicist Nick Herbert expressed some reservations about them in his own book "Elemental Mind"). Culbertson described a set up quite similar to Jonathan Harrison's.

  4. No phenomena "demand" any particular hypothesis. The postulate (1) that phenomenal space and physical space are ontologically different spaces (each a different slice of a higher-dimensional space) is one hypothesis. The postulate (2) that phenomenal space is somehow entirely "generated" by the continued function of the CNS is another hypothesis. The former runs into alleged problems with Occam's razor: the latter runs into real problems with Leibnitz's Law of the Identity of Indiscernibles. Also proponents of hypothesis 2 do not explain how brain activity generates a real space.
    Re "space" v "geometry": would it be true to say that space exists quite independently of humans, whereas geometry is a human endeavor? Another view is that space does not exist—only objects (or the quantum energy field) exist and these have spatial relations to each other. But then can empty space, lacking both objects (contents) and the quantum energy field, properly be said to exist? Theory 1 suggests that phenomenal space contains events—i.e. sensations changing over time: the Identity Theory (2) claims that these phenomenal events are identical to certain brain events. Neither postulates an empty space.

  5. Pt. 1. That a given phenonemon, observation, set of observations, or scientific findings "demand" one theory over another to explain them is a figurative usage in the philosophy of science that refers to logical necessity (or logical entailment): "that state of things that obliges something to be as it is because no alternative is logically possible." (OED) This is the so-called "necessary and sufficient condition" for something to be true.

    To postulate a special region (slice, section--whatever) of space-time to account for the space (-time) of sensations is fine for the purposes of science fiction, but the principle of parsimony would tend to oppose it, because it is not clear that it is *necessary,* and nothing in physics seems to prompt it either. Occam's razor states that entities must not be multiplied beyond necessity ("entia non sunt multiplicanda praeter necessitatem"). How does one then establish the necessity to theorize that there is such a special "slice" of space-time for sensations? That is what is meant by facts "demanding" a certain explanation over any other.

    If, as Schroedinger claims, sensations have been deliberately omitted from the picture of the world formed by the physical sciences, then it seems to me that the most logical tactic is to put them back in--just as Mach argued 100 years ago in his "Analysis of Sensations." We must analyze exactly *how* they have been omitted from the physical picture in order to restore them to it.

  6. Pt. 2 Whether or not space exists independently has been a topic of much deliberation among philosophers and scientists for centuries already, so no need to rehash that here. Suffice to say that Einstein argued that objects are spatially extended, and that "space" is really just an abstraction meaning "spatial extention," so the idea of "empty space" is without meaning, at least in the physical universe. That is because "empty" physical space is not empty at all, and is pervaded by all the physical forces of the universe, not the least of which is gravitation.

    Oddly enough, it seems only in the perceptual world that the idea of "empty space" has meaning. To the best of my knowledge no one has ever done an epistemological analysis of the concept of "empty" perceptual space to determine upon what perceptual experiences the notion rests.

  7. In ordinary language we speak of an "empty room," which I suppose might be the origin of the idea of "empty space." It refers to a container (a room) being empty, whereas outdoors we do not say that a given region is "empty," because there is no enclosure. In German the word for space is "Raum" which can also mean "room," especially in the sense of "room enough" to put something (an object). "Leer" is the German word for "empty," so a "leer Raum" can be both an empty room and an empty space. The Latin word "vacuum" simply means empty space or void, but no doubt in the same concrete sense (at least initially) as an empty room. There is a large German literature that deals with ordinary ideas about space, little of which is available in English.

  8. We could really use here some contributors who are working on the philosophical problems of space and time!

  9. I think that we need to be a little careful here in the context of talking about Mach, since he was a phenomenalist, and didn't, for example, believe in an independent existence of atoms. I think that it would be quite useful though to get a discussion going about the relationship between the two spaces, and in particular about neural causal correlates (whether this is one to one or some other relationship) with events in visual space, or phenomenal space in general.

  10. Mach called atoms "things of thought" because they did not jibe with the characteristics of sensations (yes!) His version of phenomenalism was more a criticism of the validity of the "picture" of the physical world formed through measurement and mathematics in physics, rather than through sensory experience.

    But phenomenalism came back into physics through the back door with Q.M. in conjunction with the so-called "observer problem." It prompted Niels Bohr to exclaim that "no phenomenon is a phenomenon until it is an observed phenomenon." John Wheeler expanded that idea into his so-called "observer-participant" theory of the universe, that argued the universe is brought into existence through observation (!)

  11. Part 1. I do not think that Broad,Price, Russell, myself and Bernard Carr were indulging in science fiction when we postulated that phenomenal space and physical space are different sections of a common higher-dimensional space. Obviously current physics does not "demand" it, because current physics is not focussed on phenomenal events. The possibility of higher-dimensions in this context arises when one tries to integrate phenomenal and physical spaces—or thinks "how to put sensations back into the world". But brane theory in current physics suggests that such parallel universes may exist, although, at present it is fixated on seeing them as containing only variations on what our physical universe contains, although logically a parallel universe could contain anything.
    One reason for "suggesting" this theory is the fact that its main rival—the Identity Theory—is logically impossible on account of the fact that it flagrantly breaks Leibnitz's Law. Moreover IT gets into hopeless tangles when it tries to account for how the brain, as a machine, produces the visual field (and other such) that we experience. Secondly, whether such extra dimensions do or do not exist, I suggest, is a matter of empirical fact, and that is not a matter that can be decided by appeal to Occam. I have suggested one way to test the theory by experiment (by a further investigation of the Ehrenhaft phemonena) in "The Walls of Plato's Cave".

  12. Part 2. Bill's remark that we need an epistemological analysis of the concept of empty phenomenal space is right on target. What could "empty" phenomenal space be like? One answer might be what people without a functioning visual cortex "experience" visually—what they describe as "nothing": but what sort of "nothing"? Any answer from surrealism, Bill? Also Bob is right on another target with his comment. We did to do much spade work there. I doubt if philosophers could help—but a comment here from Bernard would be really helpful.

  13. In response to John's response (Pt. 1), I believe this may well illustrate another example of reasoning by analogy. It is a topological way of formulating the problem (or more than one problem), but generally saying that sensations are in some other place than the physical world. I'm not sure who was the first one to propose this idea, and why.

    Dimensionalization of measurements or data is common in mathematics (and especially mathematical physics), based as it is on the sole criterion of orthogonality. It is used extensively in multi-dimensional scaling in psychology as well. The question is the *reality status* of such dimensions, whether in mathematics, physics, or psychology. I don't think that thus far we have seen anything in the characteristics of VS that would compel one on the face of it to believe that it occupies orthogonal dimensions to those of the physical universe, and I frankly don't see the relevance of the Ehrenfels phenomenon, except again as a kind of physical analogy suggesting a dimensional (or topological) model, whether abstract or putatively real.

    The problem comes back to how literally to take such analogies. How useful are they? Analogies are useful in general only insofar as they hold. The basic mistake in analogical reasoning is to suppose that two things that are analogous are analogous in all ways. In this instance, it comes down to one main question: is the relationship between the physical world and perceptual world best formulated in terms of orthogonality? Both Mach and Schrodinger would probably argue against them being mutually exclusive, since our knowledge of the physical seems inextricably bound up with and indeed derived from the perceptual.

  14. I am not sure how much I can help here, but I am both a realist about quantum theory (see my website and thus disagree with Wheeler that quantum phenomena depend upon observations. I am also a realist about phenomenal space, but it is not obvious to me that the dimensions of the two spaces are orthogonal. I think it would help to try to sort out what evidence we have for neural causal correlates. For example how good is the evidence that neural correlates are from the cerebral cortex and not other areas of the brain?

  15. Here is a note on orthogonalocity in brane theory from John Gibbon's chapter on the evolution of universes in his new book "In Search of the Multiverse":—
    "Material in a black hole falling towards the singularity might be diverted into another set of dimensions that expand to become a new universes, The new space-time is easy to describe mathematically in terms of dimensions—three of space and one of time which are each at right angles to all the four dimensions of our own [the parent] space-time." To take up Bill's and Bob's point, I agree that it is not "obvious" that the dimensions used to locate events in phenomenal space are orthogonal to the dimensions used to locate events in physical space. This is just an hypothesis to be tested like any other hypothesis in science. If we only tested obvious hypotheses we should not get very far!
    Re the Ehrenhaft effect—Professor Ehrenhaft described dust particles in a strong beam of light in a low vacuum behaving in a way he could not explain. Many years later Frank Nelson and I confirmed these findings at the Edison-Swan Electric Light bulb factory. But we did not have the apparatus to investigate the fascinating patterns further. And, as Ehrenhaft was regarded as an eccentric, no one else did a follow up. A pity, for in a field over-full with speculation, I feel any chance of doing experiments, however small the chance of success, should be grasped.
    Even if you fail to support the hypothesis you were hoping to support, nevertheless the history of science repeatedly shows that you may turn up something esle of value.

  16. Responding to John's point, again, I am not sure how useful analogies from cosmology are, whether an analogy is made to the creation of new universes from black holes or to brane theory, because those theories are intended only to explain *physical* things, not perceptual ones. For that reason I do not see the relevance between the unexplained Ehrenhaft dust particle effect and this problem, as there are many such physical phenomena in want of an explanation. What is the connection?

    As nearly as one can determine, the relationship between perceptual space and physical space is epistemological unique--sui generis.

  17. I don't think Wheeler was rejecting realism, only specifying the conditions of it. If reality is observer dependent, as Berkeley and apparently Bohr maintained, than the nature of observation needs to be fully illuminated in order to understand perceptual space which, as we presumably all agree, is observer dependent.

    If one loses the sight in one's eyes, one may continue to have visual experiences of a sort--sensations of light, and also visual dreams that persist for a time, but eventually seem to gradually disappear. However, destruction of the visual cortex seems to result in a complete obliteration of visual experience, though one question we need to answer is whether or not patients who have suffered the loss of cortical function--or have lost that brain region altogether due to surgery--continue to have visual dreams. That is a key question I should think. There are subcortical visual projections, though that are implicated in the phenomenon of "blind sight," in which people cannot see, yet respond as if they can!

  18. I agree with John that there is a lot to be said for testing implications of various hypotheses here. One that may be of relevance involves the claim that causes and their immediate effects have to be spatially contiguous (i. e., that there is no action at a distance). I also take it that there is a lot of evidence that in general the visual system in the brain works in parallel, and not serially like a TV signal. If this is the case then it would seem that the two spaces would have to overlap in regions where there is a causal connection between neural correlates of visual experience and the corresponding events in visual space. Of course this reasoning is only as good as the plausibility of the hypotheses going in, but it seems to me that they are not unreasonable.

  19. Re Bob's question about where are the visual NCCs in the brain. There seem, as far as I can make out, to be two hypotheses. The illustrious Professor Zeki thinks they are in area 17, the primary visual cortex. Certainly the recent evidence, that we see only what the brain computes is most probably "out there" and not what is actually "out there", may support this. The normal visual field is built up from the 'reality' input from the retina blended seamless with the 'virtual reality' input from the higher visual cortex. The retina reports what is out there (A). The higher visual cortex (HVC) ceaselessly computes (B) what the scene 'out there' ought to be given what happened in the recent past plus an estimate of what usually happened previously following this state of affairs. Thus the visual pathway must contain somewhere a high-level template or screen where A and B are collected and matched. Any significant discrepancy leads to activation of the N. Basalis of Meynert and activation of the cholinergic system in the cortex that controls the balance between A and B—so that attention can be focussed on the new and possibly salient stimulus.
    In Zeki's hypothesis the visual input from the retina is sent to area 17 and thence is distributed to the higher visual cortex, where it is exhaustively analysed for content. The results are relayed back to to area 17. (There are 10 times more axons going from cortex to area 17 than there are going in the other direction). The HVC also projects its predictions down to area 17. Here is where a mismatch is detected (i.e. when something unexpected occurs) and signals are sent to N. Meynert.
    The opposing hypothesis is that the template is in the HVC itself where the retinal input to layer 4 carrying A interacts with the cortico-cortical input to layers 2-3 carrying B and so unexpected events are detected. The up-down cortico-cortical projections may carry out some modulatory role. In this hypothesis the NCCs are in the HVC.
    I have not been in touch with this debate recently and there may be developments that I am not aware of.

  20. In vision science area 17 or "striate" cortex is called "V1," the extrastriate areas 18 and 19 are thus V2, and V3 (etc.), as I have referred to them in previous postings. David Hubel and Thorsten Wiesel shared a Nobel Prize with Roger Sperry in 1981 for their pioneering work in mapping of visual areas and hemispheric lateralizaiton, respectively.

    I don't share John's view that the brain is "computing," though, nor that it is engaged in creating virtual reality, simply because in virtual reality a person can in principle compare it with "real" reality, which is something we cannot do in comparing the visual world with the physical world to which we have no direct access.

    Again, this is a potentially useful analogy--as far as it holds--but I'm not sure that it says much more than the going paradigm in cog. sci. that we maintain an "internal representation" of the world that we "update." But this doesn't just apply to "out there," but to the so-called problem of "other minds," because "out there" includes other people, and we do not have direct access to their minds, and there is reason to believe that we "model" them in much the same way as we do our "surroundings," even though they are "inside" someone's head. But much like Raymond Tallis, I have become increasingly critical of all the loose application engineering jargon, even of "input/output," "computing," etc., because as I have stated already, I believe it may obscure the truth as much as it illuminates it: The brain is not a man-made machine, yet people talk about it as if it were. Indeed, if anything, it is perhaps more like a gland, as Richard Bergland argued in his book "The Fabric of Mind," as evidenced by the now huge field of neuroendocrinology.

  21. In response to Bill, what if we are caught up in a virtual reality game, where both we don't realize that it is virtual reality, and where, short of suicide, we cannot escape from it? I think though that visual space usually does give a good model of at least macroscopic properties of they physical world, it is just that we need the methods of science to gather pretty indirect evidence for the way that world actually exists.
    I appreciate John's points, and agree that the visual cortex is probably as good of a candidate for the immediate neural correlate of visual space as anywhere. A hypothesis, which if either of you can conclusively refute I would be quite interested, is that the superior colliculus is the correlate. I realize that it is not usually considered to be such a center (and has been considered as controlling eye movements and possibly blindsight) but it evidently does have coordinated mappings of audition and touch along with vision.

  22. The superior colliculus has a very simple mode of operation. The retinal input is displayed as a topographic sheet in the superficial layer spread out on the top of the motor output inferior layer, so that an S ('fly') coming in triggers activity in a spot in the superior layer directly over the spot in the inferior layer that directs the frog's tongue to grab the fly. I doubt if the SC in humans has the capacity to hold the entire visual field in enough detail but the same principle may apply to the layers of the cortex. Only here a mismatch between cortical activity in layer IV versus layers 11-111 (between reality and prediction) might trigger a signal to N.Basalis as detailed above.
    If Bill does not like the term 'virtual reality' we can replace it with 'predictions' (better than Gregory's term 'hypotheses'?) which the hard experimental and clinical evidence shows the visual brain certainly is making all the time (and which sometimes win out over the competing reality interpetration as in the monkey and leaves experiment). Odd though that there does not seem to be as much of this going on in the auditory brain.
    However, in the various experiments I quote in my papers, it is not the case that the subject compares his "visual world" with the physical world to which we have no access—as a conscious observer might try vainly to do, because I completely agree we cannot do this as we have no direct access to the physical world. What I am talking about is something quite different—the completely unconscious comparison that the brain makes between the actual visual input coming from the retina, and what the brain's memory and prediction systems predict as what should most probably be seen in those particular circumstances. The fact that this is going on has only been discovered recently when it was teased out by subtle experiments.

  23. Overlapping sensory "maps" are found in many species, and of course, this has fuelled speculation that perhaps because we experience a perceptual world in which the senses are integrated, such a site in the brain might be closely associated with conscious perception because of congruence. For example in the optic tectum of retiles there are overlapping retinotopic and infrared maps (!)

    The problem, as I see it, is that all these various areas seem to work in concert in generating conscious perception--or are at least in some way involved in it--yet to make VS congruent with the various visual areas, cortical and subcortical, is topologically impossible, because the principle of congruence is violated.

    As for the brain making comparisons rather than hypotheses, or even the "unconscious" doing that, is still to anthromorphize individual parts of the brain (or mind) into doing what whole conscious people do. This basic conceptual pitfall is examined at length in Raymond Tallis's little book, because if not corrected for, leads to the need for a homuculus--which is just another way of saying that the conceptualization is explaining what the whole person does consciously, and thus has gone afoul. Most of neuroscience has fallen into that trap, alas.

  24. Given Bob's comment above, I suspect he may agree with me that part of the problem may be that different senses of the words "real" and "reality" are being conflated, and therefore have a tendency to lead to insoluble puzzles. This is a sort of unintentional equivocation of which we are probably all guilty.

  25. I agree Bill, the word "real" can have many different senses and people can argue past each other because they use it in different ways. J. L. Austin has a nice discussion of it in Sense and Sensibilia where he contends that the negative usage is the "trouser word" in that something can be "unreal" in several distinct sharply defined ways, such as being artificial, fake, toy, a picture or image etc., and something is then characterized as being "real" because it is not "unreal" in one of these senses.

  26. Quite so, Bob. Reification is another problem, in which purely abstract entities are given a reality status equal to any ordinary sense of reality (mathematicians are particularly prone to this in creating "mathematical fiction").

    The old 19th century doctrine of "localization of function," that still persists and pervades neurology and neuroscience today, is probably the chief source of misconception.

    I was reminded of this yesterday when I took my old Volvo in because the dashboard lights and tail lights had ceased to function. I feared the worst, that it was an electrical short, would be expensive to repair, etc. Turns out two fuses had blown--$12 total repair--but it was enough to render one whole part of the car's light system non-functional.

    The fallacy of localization of function arises by attributing to a certain brain area what may actually be a function of a whole system--in the context of this discussion, whatever controls visual consciousness. Obviously in normal circumstances one needs a light source, eyes, and brain in order to see--not just a visual cotex.

  27. It looks like the current research of Jan Koenderink and his associates in Holland is addressing a number of the issues we have been discussing about distortions of visual shape, and what constitutes straight lines and planes in visual space. Here is a link to their most recent paper on this subject, "Does monocular visual space contain planes?"
    Hopefully either he or one of his associates may join our discussion.

  28. Thanks for the information which you gave on the superior colliculus John and Bill. I also think that you make some good points Bill that functions may not be sharply localized in the brain. It seems like we do need some new hypotheses to try out with respect to the issue of neural correlates of consciousness. Also, if either of you come across cases of people surviving the loss of the tectum (assuming that this is possible) and what this results in, I would appreciate it if you would inform me.

  29. I have abstracted some significant papers from Pubmed on the role of the tectum in consciousness. The most significant is by E.H. Strehler in "Where is the Self: A neuroanatomical theory of consciousness." (Synapse. 1991 Jan;7(1):44-91.)
    The key statement is
    "It was discovered that only one brain structure receives the prerequisite information from the sense of vision plus information derived from cortical memory stores plus a variety of other relevant sources needed to generate a coherent sense of selfness. This structure is the superior colliculus of the tectum. The superior colliculi not only receive a highly precise retinotopic representation of inputs to the eyes, but also receive inputs from a great variety of other structures, including many areas of the cerebral cortex, vestibular inputs, auditory inputs, "affective" inputs, and inputs that putatively define the positions of the eyes and of the head. This information, it is deduced, not only allows this structure to generate a continuing synthesis of representations of the self-vs.-environment, but also allows a part of it to assess the significance (probable meaning) of these integrated inputs with respect to the selection of an implementation of actions that serve the interests of the physical structure in which the self-experience is generated."
    I have put the others on a file and have e-mailed them separately on account of their length. Supportive of your ideas Bob!

    Bill's comments on the role of of brain v person in 'comparisons', 'hypotheses', 'computations', etc., etc. open up a fascinating theme for debate, as this issue, raised by philosophers, has very largely been ignored by neuroscientists, and consequently there has been very little exchange of ideas on the issue. I grant that there has been a somewhat free-and-easy attitude in neuroscience and neurophilosophical circles to statements like "the brain thinks", "the brain believes" and even "the brain falls in love". On the other hand we need an exact technical wording to describe what the brain actually does in both conscious states and unconscious reactions. Also the role of the "Self" in all this has been relatively overlooked by both camps. However, this seems to me to stray rather too far from the theme of this blog: it needs another blog all of its own.

  30. "Appearances can be deceptive," as the paper by Strehler exemplifies, being a veritable tour de force in localization of function-oriented conceptualization, notwithstanding any or all of the criticisms that have been leveled against the notion for decades now.

    For one, Strehler does not explain very explicitly what exactly he means by "self," but instead seems to be talking about the perceptual body in relationship to the perceptual world, without explaining how the "self" sort of got lost along the way--let alone why it is conscious.

    In the 20 years since Strehler's paper was published, behaviorial neurbiology has apparently settled down to conclude that the SC is apparently involved in visually-guided behavior, given its role in eye and head movements, and what happens when it sustains damage vs. what happens when the cortical visual areas are damaged.

    Even if the SC was a neuroanatomical candidate for creating/controlling VS (for one), what is it about that region that would make it conscious and the rest of the brain not?

    I feel like quoting what Sgt. Joe Friday used to say in the TV police show "Dragnet," namely, "Just the facts, m'am, just the facts!" He was really echoing Sherlock Holmes who was always at pains to see the data first before drawing any conclusion. Strehler's account is so laden with assumptions and interpretation that it is hard to separate just what the "facts" may be.

    The problem with all attempts to identify consciousness--let alone the mind--with the brain, boils down to this: just what is it that that identification consists of? Are we identifying sensations with electrical activity? The behavior of neurotransmitters? Protein metabolism? The fact that the *substance* of sensations, whether visual or of any other sense modality, seems so remarkably stable and noiseless is at odds with the intensely dynamic nature of such physical correlates as I have named.

    It is for this reason that William Sickles proposed that sensations are identical with liguid crystals, paracrystalinity being exemplified by digital displays in watches, that seem solid yet can behave like a liquid (thus the paradoxical name "liquid crystal"). Perhaps the "stupidest" example of a substance in the body that can assume a paracrystaline state is cholesterol! Of course this only begs the question of *where* such a paracrystaline perceptual world would reside, if in the brain, because it would presumably be several orders of magnitude smaller than even a single neuron...

  31. I have often thought that in turning to cosmology for models we may be looking at the wrong scale of structure, and that perhaps we should be looking at the other end of the physical continuum, as Sickles did. Of course there are a number of physicists who have floated ideas that consciousness is indeed rooted at the level of quantum reality (whatever that might be), whereas for unstated reasons neuroscience always seems to assume that consciousness must be a more macroscopic phenomenon, at the level of cellular activity, much like some sort of secretion.

  32. It's partly a matter of levels. The tectum does one thing in primitive animals and gives over much of this to the cortex when that develops. As you know, I do not think that phenomenal consciousness is located in the brain, be it cortex, tectum or anywhere else. But, as you say, why should NCCs not be liquid crystals—if you can make a case for that. The stroboscopic patterns might give one a lead.
    Yes, I agree one needs to be more sophisticated about the Self than Strehler is.

  33. I suppose the example of SC function being taken up by the cortex is an example of the evolutionary processs of "encephalization."

    Lord Russell seemed to say that it was the logic of *physical* causality that perceptions were inside the head, given the seemingly unidirectional sequence of light -> retina -> brain -> consciousness. The problem is the last link in the chain: brain -> consciousness, because the presumption is that it, too, is a physical-to-physical causal link or stage, yet it is unlike any other link known to us.

    I don't think in making his argument for a causal theory of perception that Lord Russell had in mind that the causal sequence suddenly took a right turn (literally) and went into another space-time manifold that is non-physical, as John suggests, and which I doubt Russell would endorse.

    So one is left with two possible alternatives (at least): either (1) physical causality is wrong (so-called "classical" casuality in physics), at least as it pertains to this causal sequence, or (2) the causal theory of perception is wrong. Culbertson, for one, rejected both (1) and (2) in his theory of consciousness, in arguing that sensations occur before brain processes.

    But it seems to me that we already have enough brain evidence to suggest that something does not equate, if much to the distress of those who are heavily invested in the psychoneural identity theory (which does not include me). I don't think dimensionalizing the problem per se will solve the problem, though (pace, John), for the simple reason as I have already stated so much of the our picture of the physical world seems to derive from the perceptual one--even in today's physics.

    In the mid-1980s I had the idea that sensations indeed exist in the physical world as naturally as atoms, but have not been detected by instruments because they differ only in quality, not in any quantitative and thus measurable way. How would a physicist know if he was measuring a blue atom or a yellow one? In other words, sensations could represent an aspect of reality that has simply gone undetected by science because it is unmeasurable. Scarcely and ironically can I call it an aspect of *physical* reality, for the simple reason that such "secondary qualities" have been excluded from the nature of the physical world. It has occurred to me that the only way this sensory order makes itself known is through our consciousness and through psychic phenomena (or paraphysical phenomena), which seem to thumb its nose at physics--that and so-called "UFOs" which defy all the laws of physics. I have often wonder if those phenomena are telling us that there is an aspect of our collective reality to which science is completely blind, because it falls in science's "blind spot," if I may be pardoned a visual analogy....

  34. Science, in its hauteur, never seems to have even posed the question that perhaps Nature might make things or consist of things that its instruments cannot detect because they only differ in quality. Yet I seem to recall it was Occaam himself who posed just this possibility long before the rise of modern science. I remember this coming out in a philosophy graduate seminar at UCSD in the 1980s--one not attended by the Churchlands--in which one of the students expounded on Occaam's subversive views of how God might just bedevil in this way! He actually quoted Occaam chapter and verse, too, and I was astonished at how contemporary his thoughts sounded, seeming to face squarely the whole problem of so-called "qualia."

  35. Many thanks for the references on the superior colliculus John. I do think that the mind body problem is wide open (even though many people think that it is a pseudo-problem for various reasons) and I have always found the superior colliculus to have intriguing properties concerning coordinations among different sensory systems, so I have considered it to be a possible candidate for the center of conscious experiences, but there are other candidates as well including cortical projection centers.
    One point concerning the concept of the self. There is a famous passage from David Hume's Treatise of Human Nature where he speaks of searching his mind for his "self" and just encountering various other sensations. I agree with Hume here, if not on much else, I don't know as there is a self apart from our various conscious experiences, and there are certainly regresses if one talks about a separate self which is conscious of the experiences. The very existence of a space of the experiences is enough for me. I think that maybe the best that we can do as far as forming theories of neural correlates for the experiences is to test out various hypotheses and point to considerations either in favor or against them. I also think that it would be a good idea if we could get some more people in on the discussions.

  36. Yes, it was very good indeed of John to dig out those references to the SC literature so as to see if they might shine a light on all that is dark to us. But these papers are also a source of frustration because in a way what they are really doing--or trying to do--is amateur philosophy. Pat Churchland called it "neurophilosophy" with her book of that title. They are using the brain to philosnophize with, as it were, advancing fancy-sounding terms like "neuroepistemology" which psychologists Sigmund Koch might have dismissed under his rubric of "epistemopathology," requiring under his skilled hands an "epistemopathectomy" to set straight.

    Trouble is, most of the philosophizing in neuroscience is constrained and thus unproductive because it presupposes a neuroreductionist framework as its foundation, rather than at the same time challenging its assumptions. Because of that, "central state materialism" and "promissory materialism" persist as they do in neuroscience as a field because, I suspect, the philosophically-minded but philosophically naive have been drawn to neuroscience with the expectation that they will be able to solve the mind-body problem through it once and for all.

  37. That said, some philosophers haven't done much better, those such as Ryle who would like to just categorically dismiss the mind-brain problem as a pseudo-problem as Bob suggests, or "explain it away" by various arguments--usually fallacious ones as it turns out (Fodor, Dennett, Searle, et alia).

  38. John, as we have now been looking at it these past several weeks almost daily, could you apprise us of the significance of the Marie-Therese thaler? You mention Plato...

  39. 1. Re Russell. This is what he said
    "The objects of perception which I take to be ‘external’ to me, such as coloured surfaces that I see, are only ‘external’ in my private space . . . When on a common-sense basis, people talk of the gulf between mind and matter, what they really have in mind is the gulf between a tactual percept, and a ‘thought’—e.g. a memory, a pleasure, or a volition. But this, as we have seen, is a division within the mental world; the percept is as mental as the ‘thought’." and again
    "All this [the physiological account of perception], I say, has long been a commonplace, but it has a consequence that has not been adequately recognised, namely that the space in which the physical
    table is located must be different from the space we know by experience.’ Lord Brain (1955) says much the same ‘. . . it is essential to recognise the distinction between the space of perception and the space of physics, and between phenomenal
    objects and physical objects’.
    One reply to Hume, when he was searching around in his consciousness looking for his Self, and failing to find it, is to ask him what was doing this searching (appears as "O" in psychophysical experiments)?

  40. 2. Bill's remark that NCCs as liquid crystals in neurons must be very "small" jogged a thought "small relative to what?". In the phenomenal world entities have a definite size, relative to other entities:e.g. one after-image may be observed to be larger than another. Likewise in the physical world one object is judged 'small' or 'large' relative to other objects. But how can one judge if an after-image is larger or smaller than say a plate in the physical world? The point of this is that a person's phenomenal world at any one moment (A) may be tucked inside a very small part of the brain (B) and no one could tell. The only constraint seems to be that the information content of B cannot be less than the information content of A.

  41. 3. More on Russell:

    Broad (1923) puts it thus:
    "For reasons already stated, it is impossible that sensa [Broad’s term for sensations]should literally occupy places in scientific space, though it may not, of course, be impossible to construct a space-like whole of more than three dimensions, in which sensa of all kinds, and scientific objects literally have places. If so, I suppose, that scientific space would be one kind of section of such a quasi-space, and e.g. a visual
    field would be another kind of section of the same quasi-space.
    Kuhlenbeck (1958) says that ‘. . . physical events and mental events occur in different space-time systems which have no dimensions in common’ (as did H.H. Price).

  42. I shall reply in a separate posting to the views of Russell, Broad, Kuhlenbeck, and Price.

    The point about the size of percepts was relative to the difference in scale between celluar events (the neuronal level) and that of the molecular level, the scale at which Sickles envisioned the visual percept to be constituted as, he put it, a tiny "piece of space lattice." To state it differently, Sickles was conceiving the VS in its entirety at any given instant to be smaller than a single neuron, through the process of progressive shrinkage of the visual simulus pattern conveyed through the visual system. How this would "work" geometrically (or topologically) is another matter, because the visual "information" would be already distributed over many cells and cortical area at V1.

    Nonetheless to reduce the pattern in toto to the molecular level let alone to a single molecular structure (presumably in the protoplasm) would seem difficultb to even conceive, except when one recalls that all of us begin life as a tiny fertilized ovum regulated by DNA, and the corrolary theory that memories are encoded in RNA.

    If we are going to appeal to engineering analogies, perhaps they should be molecular engineering models, rather than computing machines. I cannot even begin to do justice to the late Dr. Sickles' quite extensive biophysical analysis justice here (which he developed over a period of 40 years, his point of departure being Gestalt theory), but I can say that his argument is both closely reasoned and supported by research in biophysics and physiology. On a manuscript he sent me (now some years ago) he noted: "The thesis here is that the brain is a large, varietistic gland--not an assembly of microchips." He had reached that conclusion some time before neuroendocrinology as a field came into its own.

  43. Yes, Bill, the current narrow focus on electricity in the brain leaves out a lot. What molecular engineering models were you thinking of in particular?

  44. I should think DNA nanotechnology might be worth a look, especially as B-DNA involves paracrystalinity:
    It is thus relevant to Sickles' proposal that the basic "information" medium of perception is the same as that of life in general and memory respecitvely: DNA and RNA. If VS is supported by a memory component, Sickles would probably argue that it involves RNA's molecular "machinery."

  45. Update on my antique Volvo's dashboard and tail lights: After they mysteriously went out once again, it became apparent that it was not the fuses after all. Turns out that though the fuses were blown again, the real problem was the wiring in the tailgate that had a short in it, due to wear and tear from opening and closing the tail gate of the car. The mechanic told me that the cashier's son had a similar problem of fuses blowing, had substituted a higher voltage fuse, only for it to blow--and it turned out his windshield wiper wiring had gotten wet, and was shorting and blowing the fuse.

    The reason I mention these mundane details once more is because with an electrical circuit it would be a mistake to localize the function of the whole circuit in a single portion of it, and it is not even clear that connections in the nervous system can properly be called circuits, even though electrical potentials are being generated and moving down axons. So even the analogy of a circuit may be misleading, which gives all the more pause to question what it is that is being localized in the brain's visual areas?


Note: Only a member of this blog may post a comment.