Imagination and Causality in Quantum Physics

[Ellen Stuttle]

Paul, to spare your wondering what connections I might see between your views and those of Donavan Hall (not the correct Hall), I went searching for the name of the Hall I'm thinking of.

The name is R. Stewart Hall. I found it in an Old Atlantis post by his proselytizer, Everett E. Allie ("Humanity's Ultimate Challenge"), who used to try to interest Atlanteans in Hall's physics, and in Allie's conclusions pertaining to the social world. (Allie was of the opinion that certain conclusions about human society followed as the night the day from the physics. Some of us made halfhearted attempts to rebut this argument, saying that even if the physics were true, Allie's social theories wouldn't follow. Allie wasn't listening, and no one wasted time in a sustained effort to convince him.)

Allie's website is still up. On a quick glance, I don't see any indication of when it was last revised. Whichever year that was, Hall had turned 90 on February 14th of (see the text below).

http://www.speciesup.org/

Here are excerpts which give the general idea:

=== Start Quote

Objective reality, in terms of its fundamental , mechanisms, functions and prinicples, stands alone, impervious and inviolable.  At its most fundamental level, structure is generated as cycling ring systems of the fundamental unit volumes, developing into atoms and all higher constructions.  The foundation particles exhibit massless motion at the speed of 'c', the speed of light and the fundamental speed of Existence.  These fundamental systems constitute the physical matrix out of which all things develop throughout a boundless and ever changing Universe.   (See Analytic MetaPhysics under 'Resources')

The factual, fundamental nature of Existence was discovered over twenty years ago and cannot be refuted, The proof is so comprehensive and obvious, few even try. Their defense mechanisms are largely aversion and silence. Further, neither can this new knowledge be recognized and effectively disseminated within present instituted social systems that accommodate the dementing delusions..

   The discovery of the definitive foundation of Existence included the foundation unit volume of Existence, the 'Genesis Particle'. This is the necessary foundation of any and all developing structure, particles with an intrinsic speed of light that form interacting ring systems of cycling movement. This, the fundamental nature of Existence, cannot be refuted nor made to be other than in fact it is, but it has been 'stonewalled' by all institutions contacted.

   This discovery shows that Theoretical Science, including Theoretical Physics and Cosmology, is fundamentally misdirected and functions to accommodate the instituted belief in myth and magic.. This new knowledge is mutually exclusive with a Creation Theory, in a Big Bang or otherwise.

   By showing what structure 'is', and how it works, all other physics phenomena can be accounted for, and addressed as well. Both Physics and the Universe are truly unified. This is knowledge that could ultimately dissolve religious belief and unify our species, allowing us to make fundamental corrections and become sustainable within the Earth environment. There is never conflict over known reality. Virtually all conflict, globally, is generated by belief, which is, by nature, mutually exclusive with every other belief.

   The details of this discovery, and the new Physics system it spawned, are now available to anyone in a book entitled "Analytical MetaPhysics, A New View of the Cosmos", 2002, by R. Stewart Hall, ISBN: 0-7596-5252-X . Hall is a retired engineer from General Electric Co. and Allison Division of General Motors. He lives in Hollywood, Florida and had his 90th birthday February 14th.

   To date, scientists within the major Physics Institutions, globally, have been sent the new material, regarding the discovery of definitive fundamental Existence, yet none have acknowledged it. The major media institutions have been contacted, as well. From all this, over the past decade, we received but one comment from an institution, The University of Chicago Press. The reply comment stated that the material was "Compelling" but that they would not publish the work. None of the Physics Institutions have responded. The material was finally published through 'on demand publishing' as "Analytic MetaPhysics".

   The problem is that this discovery shows 'structure' to be generated by stable patterns of cycling motion at the speed of 'c', light speed. Motion is seen to be intrinsic to matter. The fundamental particle has an intrinsic speed of 'c' and these come together to generate cycling, spinning ring systems that constitute physical structure.

   This shows that all energy and fundamental control is mechanistic, intrinsic to the foundation particle, the Genesis Particle, if you will. Existence is seen to be a Continuum of ongoing development, degeneration and renewal through gravitational recompression.

   All matter has the same basic structure, 'ring systems' that provide the structures of electrons, gammas, photons, nucleons, atoms, molecules and all further development.

   Matter is forever drawn together, but with limitations as to how much can be compacted before the mass becomes unstable. There was no Big Bang, only endless ongoing lesser bangs.

   The 'Principle of Physical Primacy' is necessary to any organization. There can be no organization in the absence of physical structure to generate and maintain that organization. This holds true for all physical development, as well as for any 'aspect' of the physical, e.g., for an individual or for a thought, dream or feeling.

~~~~~~~~~

   Just as the Universe, and every entity within it, is naturally  autonomous,  the human mind organizes itself around its foundation concepts, the internalized cognizance that provides the individual with its 'subjective reality', its personal view of what constitutes reality.

   To the degree this internalized 'reality' is a workable refection of objective reality, the individual is effective, operating in harmony with Nature. Where that cognizance is divergent from reality, the individual and the society is misdirected accordingly. There are no discrepancies in objective reality.

    Human behavior is determined by the concepts the individual has internalized.  The individual is naturally autonomous, the    mind organizing itself around the concepts that provide the individual's view of 'reality'. However, when delusion is taught, instilled and instituted, both the individual and the society are programmed for insanity.

        This is the case of all human societies today. Individual and Culture effectiveness is inversely proportional to the amount of instilled and instituted delusion.

=== End Quote

Ellen

___

Edited October 3, 2006 by Ellen Stuttle

[Paul Mawdsley]

Ellen,

Thanks for that. It seems I was barking up the wrong tree. Oh well, sometimes barking can be an end in itself.

After reading what you posted and following links that led me to a very brief editorial review of R. Stewart Hall's book, I was left with a single image in my head: the image of Rutherford's raisin bun atom. From the naivety of the understanding of social dynamics that must be behind the social statements, to the simplicity of the ring images from which reality is constructed, I would have to say this is not a worldview build from a particularly evolved view of causation. I readily see where you can connect Hall's statements with mine. How he imagines the physical nature of the foundations of existence is definitely pointing in the same direction. But, from what I can tell with the information I currently have, his worldview is as far removed from what I see as Rutherford's atom is from the view of the quantum atom with electron shells. It lacks causal complexity.

I get the sense you do not have time to participate much in further discussions of this nature. That's too bad for me. I'm going to keep writing though. I'm thinking of writing next on how to visualize the dynamics of non-local, non-linear physical systems. It will be an attempt to show, in principle, how a type of information can travel instantaneously over large distances even if we suppose a physical limit of the speed of light. An earlier attempt of mine was quickly shot down by Dragonfly on NB's Yahoo forum. I learned a lot from that. I won't make the mistake of underestimating my audience again. Your input is always welcome. You know you are one of my favorite on-line acquaintances. I have a lot of respect for the non-linear thinking side that comes through every once in a while. Of course, I have a lot of respect for the analytical side too.

Paul

(Edit: Sorry! Brain fart. It should be pre-Rutherford raisin bun model of the atom. As I recall, Rutherford discovered the nucleus when alpha-particles were deflected by a small, positively charged, massive part of the atom.)

Edited October 3, 2006 by Paul Mawdsley

[Mikee]

I find articles like this endlessly fascinating:

http://www.sciencedaily.com/releases/2006/...61003143520.htm

As long as there are people who continue to explore nature and are not daunted by the complexities anything is possible.

[Ellen Stuttle]

Dragonfly,

I finally got around to reading your post 244 (again, I apologize for the delay). I confess to feeling that my mind is spinning at the way you've mushed together various competing theories of perception with no apparent awareness of the differences amongst and between those theories. An analogy to physics might help in conveying to you my sense of being at a loss as to where actually to try to begin. Suppose someone were to be discussing the atom with you, and were to put together all in one explication the Newtonian hook-and-eye model, the plum pudding model, the shell model, and the more refined quantum model. Untangling this wouldn't be trivial.

I'm afraid I haven't the time to attempt the untangling, at least now. I think we'd have to go back and forth slowly, patiently, little by little; and I'm into the stretch of the year when I have even less time than I usually have in any case for email exchange.

Thus I'll select only a few phrasings from your reply to comment on.

You wrote: "[...] we construct a 3-dimensional representation that correlates with the real world."

Question 1: What is it you're claiming we see? Do we see the world, or do we see a picture of the world?

(Your phrasing reminds me of a placard I saw at a museum in Los Alamos when my husband and I were touring parts of the Southwest and of Colorado in Fall 2001. I think the museum was focused on the history of the atomic bomb, but it included displays talking about basic theory. One of those pertained to the nature of light, and touched, in passing, on perception. The placard read: "Scientists are studying how the brain creates the picture we think we see." Eyes rolled. If that isn't a stark statement of the representational theory in its most basic form, I don't know what is. But it sounds as if that's just what you're saying, though in a bit less stark a way, in the sentence quoted from your post.)

Question 2: If what we see is a picture of the world, then how is it that we can see the picture, when we can't see the world?

Question 3: And if what we see is a picture of the world, not the world, then how would we ever find out that said picture "correlates with" said world?

Another point: Your reference to the "2-dimensional image on the retina" is a red-herring, an inadvertent one I'd expect. We do not see the image on the retina (unless what we're looking at is a retina, either with opthamologist-type equipment or as a prepared retina dissected from an eye). Your phrasing reminds me of a supposed difficulty that various perception theorists got themselves into at one point back in the days of the Helmholtzian theory wondering how we manage to see the world topside up when the retinal image is reversed. Answer, just as to your phrasing: The image on the retina is not what we see. We aren't sitting there in the brain looking at the retina.

Which comment leads to another problem with what you wrote: You're attempting to avoid falling into the "Descartian theater" error, but the theory that what we see is a projection makes that error in spades. The projection theory is that of some central place analogous to the projectionist in a movie theater which puts together and then sends OUT an image (through what nerve paths, btw?), like a picture spray-painted across some sort of screen, which picture we watch as if we were watching a movie. It's a theory which enthrones the Descartian "witness program" which Dennett is trying to "dismantle."

And one last, defending my honor. ;-) (I still can't get the smilies to work; maybe I'm doing something wrong, but never mind.)

You say, in response to my reference to the problem of "the validity of the senses": "Come on Ellen, you can do better than this! [...] it sounds like a rehash of the standard randroid argument." No Randroidism involved. The problem is far, far older than O'ism. And you fall straight into the problem when you write: "the word 'illusion' does not mean that the information about the external world that we receive is incorrect [...]." How do you know that it isn't, when according to your own theory you're stuck viewing a "projection" rather than perceiving a world?

Well...maybe that will give you a bit to mull over.

Cheers.

Ellen

___

[Dragonfly]

You wrote: "[...] we construct a 3-dimensional representation that correlates with the real world."

Question 1: What is it you're claiming we see? Do we see the world, or do we see a picture of the world?

You're falling again in the trap of Cartesian dualism. "To see the world" means that we build a visual representation of the world in our brain, and that continuously updated representation in the brain is our "seeing the world", there is no interface or some dividing line between some picture in the brain that is watched by the "I", the representation is part of the mind itself.

Question 2: If what we see is a picture of the world, then how is it that we can see the picture, when we can't see the world?

See my answer on the previous question; the visible part of the world is mapped onto that part your brain that does the visual processing, so by definition there is a representation of the world in your brain, which we use to interact with that world, to move around, to grab things etc. As this representation is not the world itself, we could call it a picture, but this doesn't mean that someone inside is looking at a "picture", as in the Cartesian theatre, that "picture" is part of the looking process itself. As we usually think of pictures as things that we can look at, this term may be misleading here, so I prefer the more neutral term "representation".

Question 3: And if what we see is a picture of the world, not the world, then how would we ever find out that said picture "correlates with" said world?

I would rephrase that question: How can we find out that the representation in our brain correlates with the world? The answer is: by using it. It turns out that the representation of "something" in our brain is quite consistent, we can successfully act on it, we don't bump any moment in the walls, all the feedback we get indicates that there is something that is unchanging "out there", or if it is not unchanging, it is at least changing in a consistent way. In fact it is the consistent behavior of what we perceive that leads us to the conclusion that there is an objective reality. This in contrast to the representation of a "reality" when we're dreaming or hallucinating. The feedback we get may be the immediate feedback on our movements and actions, or the information we get from other people or through scientific experiments.

Another point: Your reference to the "2-dimensional image on the retina" is a red-herring, an inadvertent one I'd expect. We do not see the image on the retina (unless what we're looking at is a retina, either with opthamologist-type equipment or as a prepared retina dissected from an eye). Your phrasing reminds me of a supposed difficulty that various perception theorists got themselves into at one point back in the days of the Helmholtzian theory wondering how we manage to see the world topside up when the retinal image is reversed. Answer, just as to your phrasing: The image on the retina is not what we see. We aren't sitting there in the brain looking at the retina.

And I never said we did, so this is a red strawherring. I wrote: "the brain receives signals that correlate to a 2-dimensional image on the retina", and that is quite different from what you try to put into my mouth. My point was that we don't get a 3-dimensional input, but a 2-dimensional input from which we construct a 3-dimensional model, which is no trivial task as you'll realize when you try to write a computer program to do that (as I have done in times long past). BTW, your remark about the inverted image reminds me of that interesting experiment where people wore continuously upside-down goggles for several days. At first the experience is of course that everything seems to be upside-down, making moving around and doing things rather awkward, as the feedback you get is not the usual feedback. But after some days the brain adapts itself to the new, but still consistent feedback, and the world looks "normal" again. A nice example of the fact that the consistency of the feedback is what creates the user illusion.

Which comment leads to another problem with what you wrote: You're attempting to avoid falling into the "Descartian theater" error, but the theory that what we see is a projection makes that error in spades. The projection theory is that of some central place analogous to the projectionist in a movie theater which puts together and then sends OUT an image (through what nerve paths, btw?), like a picture spray-painted across some sort of screen, which picture we watch as if we were watching a movie. It's a theory which enthrones the Descartian "witness program" which Dennett is trying to "dismantle."

I said nowhere something outrageous like that. You're confusing different meanings of the word "projection". I never claimed that it was some kind of physical projection, it is a psychological effect in which in our brain a link is made between some part of the visual perception and its corresponding part in our 3-dimensional model of the world, in accordance with the consistent feedback we receive, creating the illusion that we have immediate contact with the outside world (the upside-down goggle experiment is instructive in this regard). You should forget all the talk about "looking at images", as I've never used that description. Another example of the projection we're talking about: a surgeon who is operating by using some manipulator coupled to an enlarged image on a screen. In principle the patient operated upon could be thousands of kilometers away. But if the manipulation mechanism is good enough (I don't know if mechanical feedback is used to give a better "feeling", in computer games it is already used), the surgeon could have the feeling that he's operating directly on the patient, and not via some cables or a radio connection. Professional flight simulators also seem to create a strong user illusion, so that the experience can be quite unnerving, while in fact nothing really can happen and the user knows that it is an illusion, which in this case doesn't correspond to an unforgiving real world, but to an innocent virtual world.

And you fall straight into the problem when you write: "the word 'illusion' does not mean that the information about the external world that we receive is incorrect [...]." How do you know that it isn't, when according to your own theory you're stuck viewing a "projection" rather than perceiving a world?

There are so many errors in your question that I don't know where to begin... In fact I've answered all those points already, but I'll summarize: 1. I never claimed that we "view a projection", 2. There is no such thing as "direct perception" of the world, we may say that we "perceive" the world, but this is a process with many steps, which is not infallible. 3. As long as the fraction of errors is small, we can derive with great reliability conclusions about the world. 4. It is the consistency of the feedback we receive that indicates that our perception in general is faithful, and we infer the existence errors from inconsistent results. 5. This whole system is self-consistent, no there is no contradiction. That does not mean that it is fool-proof and invariably gives the correct results. It doesn't, but all the evidence indicates that, while we never may get to know the complete reality, we can improve our knowledge continuously and get a better and better view of what it is that exists (see the progress in science and technology).

Well...maybe that will give you a bit to mull over.

Nah, that was easy. Do you have any tough questions?

[Ellen Stuttle]

Dragonfly, each time I read a post of yours on the subject of perception, I wonder if you yourself have any idea of any consistent meaning of the terms you use. (I cannot discern any consistent meaning.) "[W]e build a visual representation of the world in our brain," you say. What is "a visual representation"? Is it something seen? What, precisely, is "a representation"? (That is, according to you; I know what it is according to some perceptual theorists. Many such theorists, though, are, like you, vague in their meaning. The term "representation" has historically been used in ways which cover many sins of missing detail in various theories of perception.) It's "part of the mind itself," you say. The mind?? How did "mind" get slipped into this? And what is mind, as distinguished from "brain"?

"As this representation is not the world itself," you write, "we could call it a picture, but this doesn't mean that someone inside is looking at a 'picture', as in the Cartesian theatre, that 'picture' is part of the looking process itself. As we usually think of pictures as things that we can look at, this term may be misleading here, so I prefer the more neutral term 'representation'."

You mean, the unexplained term "representation." And you've just gotten done speaking of "look[ing] at" something, while meanwhile saying that perception doesn't involve "look[ing] at," since we don't "look at" the representation. Or do we? Now I agree that there isn't "someone inside," a sort of homunculus looking, but I don't agree that you've gotten rid of the homunculus.

I asked:

"Question 3: And if what we see is a picture of the world, not the world, then how would we ever find out that said picture 'correlates with' said world?"

You reply:

"I would rephrase that question: How can we find out that the representation in our brain correlates with the world? The answer is: by using it."

Again, what is "the representation"? How do you use "it." How do you check "it" against...what? The world, which, according to you -- if you're saying anything consistent -- can only be accessed AS a representation?

"In fact," you write, "it is the consistent behavior of what we perceive that leads us to the conclusion that there is an objective reality."

Ah, here we are "perceiv[ing]." Perceiving what? The representation in our brain?

I wrote: "The image on the retina is not what we see. We aren't sitting there in the brain looking at the retina."

You reply: "And I never said we did, so this is a red strawherring. I [you] wrote: 'the brain receives signals that correlate to a 2-dimensional image on the retina', and that is quite different from what you try to put into my mouth. "

I'm afraid that I don't see the difference. And on what basis do you say that we don't "get a 3-dimensional input"? Is the world 3-dimensionsal? (Oops, musn't talk as if we actually see the world.)

You write: "BTW, your remark about the inverted image reminds me of that interesting experiment where people wore continuously upside-down goggles for several days. At first the experience is of course that everything seems to be upside-down, making moving around and doing things rather awkward, as the feedback you get is not the usual feedback. But after some days the brain adapts itself to the new, but still consistent feedback, and the world looks 'normal' again. A nice example of the fact that the consistency of the feedback is what creates the user illusion."

Welcome to my parlor, said the spider to the fly. I wondered if you'd promptly mention those experiments, which quite contradict your theory of how perception works -- to the extent, that is, I can get any coherent theory at all from your explications, which is a very small extent. What I mostly get is key words that change their meaning from one time when you use them to the next -- as you're now saying that, no, "projection" doesn't mean "projection," but instead some kind of "psychological effect." And what is that? How does said "psychological effect" arise and operate? Is the "effect" itself a "representation"?

It's like falling down the rabbit hole. Six impossible things before breakfast, and words mean whatever you say they mean, which isn't necessarily the same from context to context. Beyond my powers of getting an actual theory from what you write.

Ellen

___

[Dragonfly]

Dragonfly, each time I read a post of yours on the subject of perception, I wonder if you yourself have any idea of any consistent meaning of the terms you use. (I cannot discern any consistent meaning.) "[W]e build a visual representation of the world in our brain," you say. What is "a visual representation"?

A representation based on information transmitted by electromagnetic radiation in the visible region.

What, precisely, is "a representation"? (That is, according to you; I know what it is according to some perceptual theorists. Many such theorists, though, are, like you, vague in their meaning. The term "representation" has historically been used in ways which cover many sins of missing detail in various theories of perception.) It's "part of the mind itself," you say. The mind?? How did "mind" get slipped into this? And what is mind, as distinguished from "brain"?

In this case I mean by "representation" a mapping of a part of the physical world onto the brain, so that it contains information about that part of the world. It is a general term, which doesn't specify how that information exactly is stored in the brain; if you want to have more specific information, ask the neuroscientists, not me. Do you deny that such a mapping exists? About the relation between brain and mind: are you asking for the sake of asking? I have explained already that in dozens of postings, many of which you'll no doubt have read, so should I repeat it all here again?

You mean, the unexplained term "representation."

I have explained it now to you.

And you've just gotten done speaking of "look[ing] at" something, while meanwhile saying that perception doesn't involve "look[ing] at," since we don't "look at" the representation. Or do we? Now I agree that there isn't "someone inside," a sort of homunculus looking, but I don't agree that you've gotten rid of the homunculus.

Sigh. For the n-th time: we don't look at the representation, "looking at something" is itself is an action of the brain that involves the processing of input from our eyes in combination with the representation of that something that we've built and continuously update if there are changes in the input. No doubt this is a highly complex process, but we use a shortcut to describe this process by saying that we "look at (say) a tree".

"I would rephrase that question: How can we find out that the representation in our brain correlates with the world? The answer is: by using it."

Again, what is "the representation"? How do you use "it." How do you check "it" against...what? The world, which, according to you -- if you're saying anything consistent -- can only be accessed AS a representation?

I've explained now to you what I mean by representation. And as I already explained in my last post (and in previous posts), there is no contradiction in saying that we check something against reality when we only have a representation of reality, as we can check for the consistency of our representation. And to repeat it again: this does not exclude the possibility that we're wrong, but the evidence is that our representation of the world in general is quite consistent and therefore may be considered to be a faithful representation of something that is invariant with regard to our feelings, thoughts and wishes, and that we call "reality".

"In fact," you write, "it is the consistent behavior of what we perceive that leads us to the conclusion that there is an objective reality."

Ah, here we are "perceiv[ing]." Perceiving what? The representation in our brain?

For the n+1th time: we don't perceive the representation, the representation is the perception.

I wrote: "The image on the retina is not what we see. We aren't sitting there in the brain looking at the retina."

You reply: "And I never said we did, so this is a red strawherring. I [you] wrote: 'the brain receives signals that correlate to a 2-dimensional image on the retina', and that is quite different from what you try to put into my mouth. "

I'm afraid that I don't see the difference.

If you don't see the difference between "looking at the retina" and "the brain receiving signals that correlate with a 2-dimensional image on the retina", you're really a hopeless case. If even such a simple and obvious difference escapes you, I have no idea how to explain anything to you. Perhaps you're too tired? Or you should reread my posts and think about them some days before you reply. You continuously reproach me for being inconsistent or vague in my terminology, but this is an example of how confused and inconsistent you are yourself when you speak about "looking".

And on what basis do you say that we don't "get a 3-dimensional input"? Is the world 3-dimensionsal? (Oops, musn't talk as if we actually see the world.)

I say that on the basis of considering the mechanisms that are used. The world may be 3-dimensional, but we don't get a 3-dimensional input, like that of a hologram. Our signal processing starts in the retina, and the information there is a 2-dimensional mapping of the 3-dimensional world. We may use clues by comparing the images from both eyes, by changing our viewpoint, by selective focusing and by interpreting different contrasts in the image to construct a 3-dimensional representation, but it is a reconstruction based on 2-dimensional images. Further, I nowhere say that you can't see the world, I only point out that it is not the simple process of "direct perception" (whatever that means, talk about vague notions...) you seem to adhere.

Welcome to my parlor, said the spider to the fly. I wondered if you'd promptly mention those experiments, which quite contradict your theory of how perception works

Not at all, they confirm the theory.

What I mostly get is key words that change their meaning from one time when you use them to the next -- as you're now saying that, no, "projection" doesn't mean "projection," but instead some kind of "psychological effect."

Now you are "projecting" your own confusion onto my argument. I never said that "projection" doesn't mean "projection", you think that "projection" has only one meaning, namely as the physical projection of an image on a screen. Apparently you've never heard of mathematical projections or psychological projections. I have already explained in previous posts what I mean by projection in this case, so I see no use to repeat myself here.

And what is that? How does said "psychological effect" arise and operate? Is the "effect" itself a "representation"?

I have already given an indication of what that I mean by projection. Yes, only in very general terms, as I don't pretend to know all the details of what happens in our brain (in contrast no doubt to your theories about the brain).

It's like falling down the rabbit hole. Six impossible things before breakfast, and words mean whatever you say they mean, which isn't necessarily the same from context to context. Beyond my powers of getting an actual theory from what you write.

That's your problem, there is nothing impossible in what I wrote. I have explained many times what the terms that I use mean, I'm nowhere inconsistent, but you keep misrepresenting what I write, erecting strawmen by continuously using your own idiosyncratic interpretations of terms that I have clearly explained more than once and then telling me that I'm not consistent. I would probably be a bad teacher, I really don't have the patience to explain the same things again and again.

[merjet]

Dragonfly wrote:

In this case I mean by "representation" a mapping of a part of the physical world onto the brain, so that it contains information about that part of the world.

This exemplifies the misuse of "representation" to describe perception.

As I say in greater detail here here

a representation requires three components. Dragonfly's description has only two. Completing the analogy takes a third component, the representer, e.g. a homunculus. Dragonfly denies there being a homunculus in his account, but something that plays that role is what is needed to complete the analogy. Otherwise, it is poor analogy.

I can agree to his use of "mapping" in one sense. One sense I would not accept is a parcel of land, a map, and the maker or viewer of the map. The map does represent the parcel, the maker or viewer is the representer, so the analogy holds. The acceptable sense is the way "mapping" is used in mathematics, but that is not a "representation."

[Dragonfly]

This exemplifies the misuse of "representation" to describe perception.

As I say in greater detail here here

I think Stephen Boydstun answered your objections very well in his last post in that thread. It seems to me more semantic quibbling about the meaning of the word "representation" than a real problem. Now I know nothing about all those representational schools, so I don't know how they use the term, I just use terms that seem to me the most appropriate and I don't see why one should limit oneself to only one of the possible meanings. The word "representation" is for example also used in mathematics (as in representations of groups) without any need for a homunculus or a representer. But if you prefer "mapping", that is fine with me (I was in fact thinking of mapping in the mathematical sense).

[Ellen Stuttle]

Dragonfly, I'm going to backtrack somewhat on this conversation, though I don't want to quote from all the way back to where I entered it, since I think that the resultant "she said/he said" would become too confusing to follow. However, I think some context is needed to show why I'm not finding your use of "projection" clear.

I came into this (specifically addressing you; I'm not referring to exchanges with RCR and with Paul) over the issue of where the pain is when we hurt a finger. I said that the word "in" is ambiguous, in similar style to the question "If a tree falls in the forest and there's no one there to hear it, where is the sound?," but that I would answer that the pain is "in" the finger. By this I mean that, whatever the details of the neurophysiological process producing the experience, what we experience is that the finger hurts, not that the brain hurts.

It was in this context that you spoke of "projection." You said that what happens is that the pain is projected by the brain so that we "think" we experience the locus of the pain as the finger. Now I'm not quoting you there (except for the use of scare quotes around "think," which is the styling you employed); I'm stating the context in which I understood you to be using the term "projection." To me this conveys a spatial idea: something which is "sent" from one locale to another, something which actually occurs here (in the brain) but which is felt there (in the finger), at a different place from where it occurs, giving us the "illusion" that it's occurring at the place where it's felt. (You sometimes used "illusion" in scare quotes and sometimes spoke of the user illusion. I expect you're borrowing that latter term from Dennett. As I understand your usage, you employ "user illusion" more widely than he does; but I'll leave that issue aside for now.)

I listed as (2) in my list of summary critiques: "[Your, DF's, perspective] resorts to a mechanism -- 'projection' -- which amounts to saying 'somehow' in scientific-sounding language."

You replied in part (past #244):

First, I don't see why that mechanism of "projection" would be so mysterious. It is the result of the way we interact with the physical world. With our eyes and our proprioception we can move effortlessly through a 3-dimensional world. This is no trivial task, however, as the brain receives signals that correlate to a 2-dimensional image on the retina, that changes with every movement we make, and yet we can in real time infer from these changes a 3-dimensional structure.

You continued by saying that "[you] think this ability is largely or even completely prewired. [but whether it's learned or not, and to what extent] is not really relevant to this discussion, however."

I agree that whether or not the ability proposed is learned or not, and to what extent (which you indicated you thought might vary in different animals), is "not really relevant to this discussion." But I differ as to whether or not what you describe even happens. Instead, I think that to consider the retinal image relevant at all to seeing is seriously mistaken, a point to which I'll return.

First, I want to indicate that, again, from anything I can gather from the above-quoted paragraph, you're thinking of "projection" as involving a spatial transfer of some sort; you at least appear to me to be thinking in terms of "a 2-dimensional image" which exists here ("on the retina") and is then translated into some sort of "infer[red]" "3-dimensional structure" somewhere else.

In elaborating you go on to say (your next paragraph) that "[...] we construct a 3-dimensional representation that correlates with the real world." You then give the example of what you describe as "us[ing] binocular vision to create a 3-d model," an example of which you explicitly state "This is an example of projection or the user illusion [...]." (Again, I think you're extending the idea of "user illusion" beyond my understanding of what Dennett means by it; I think he means the sense of a central self which is acting. But that's a side-issue to your meaning of "projection," which is the term I'm concerned with at the moment.) You also write (same paragraph, reverting to vision while navigating in an environment): "[W]e have to use the processing power of our brain efficiently, so that we have the time to construct a useful 3-d representation that correlates accurately with the real world. The result is that what we perceive corresponds closely with what happens in the real world, so our subjective experience is [...] that we are moving in the real world, that our perception is immediate" (all emphases mine).

Now all of this sounds to me as if you're talking about a something (a) which is produced at a spatial remove from the sensory input; (b ) which is "what we perceive"; and ( c) which is not, but which "correlates accurately with" the real world. If you thought that what we are perceiving is the real world, why would you say that what we perceive "correlates" with that world? I don't think I'm putting words into your mouth in concluding that you're saying that the object of (in this case visual) perception isn't the world we're navigating around in but is instead a "3-dimensional representation." Nor do I see where I'm misinterpreting in taking your use of "projection" to refer to a spatial transfer, a something seen as "there" though it's sent from "here."

However, upon my probing further, it seems as if you think that I indeed was misinterpreting in getting at least parts of the above synopsis paragraph from what you wrote. Rather than attempting to trace a blow-by-blow of most of the details of the further mutually frustrated back and forth, I'll first summarize my understanding of your corrections:

By "projection," no, you don't mean anything spatial but instead a "psychological effect," which effect IS the very process of seeing, and which effect is produced by the constant forming and updating of a 3-d representation...where? Near as I understand, you give two at least somewhat different answers to the "where" question when you write (post #255):

"'To see the world' means that we build a visual representation of the world in our brain, and that continusouly updated representation in the brain is our 'seeing the world', there is no interface or some dividing line between some picture in the brain that is watched by the 'I', the representation is part of the mind itself."

When I asked you (in post #256) precisely what you meant by "representation" and by "mind, as distinguished from 'brain,'" you replied:

(From your post #257):

In this case I mean by "representation" a mapping of a part of the physical world onto the brain, so that it contains information about that part of the world. It is a general term, which doesn't specify how that information exactly is stored in the brain; if you want to have more specific information, ask the neuroscientists, not me. Do you deny that such a mapping exists? About the relation between brain and mind: are you asking for the sake of asking? I have explained already that in dozens of postings, many of which you'll no doubt have read, so should I repeat it all here again?

Well, I'm sorry to tell you, but if you have already explained "in dozens of postings" what you see as "the relation between brain and mind," no, I don't recall your having specifically addressed that question, except maybe once. I do seem to recall (and I don't remember where, whether in a post on this list or RoR) your having said that you think of "mind" as analogous to "programs" by contrast to viewing the brain as "hardware." But if this is how you see the difference, then I'm not understanding why you'd describe the "information" which is "mapped" as being "stored in the brain," since I thought that you thought of a "program" as non-physical (though that description of itself, coming from you, whom I think of as an arch-psychicalist, puzzles me).

In any event, re the "mapping" you're speaking of here, yes, I do deny that such a mapping exists -- provided I understand what sort of "mapping" you mean. (I think that there are "projection maps" in the brain, but by this I mean anatomical structures of neurons in one part of the brain connecting to another part.) My understanding of what you mean by "mapping" comes from your speaking of a 3-dimensional representation being produced from the 2-dimensional image on the retina. However, I think that that description is mistaken. Instead:

I think that what the brain does is better described as interpreting spatio-temporal arrays of input with the assist of memory processing so as to enable us to perceive as a continuous scene discontinuous impulses triggered by the structural patterns of photons being absorbed by the retina.

Now that sentence is a mouthful. I don't swear that I'll stick with the exact wording of it. But it expresses my current understanding of how visual perception works. It's a sentence which combines Gerald Edelman's theories of brain functioning with J. J. Gibson's theories of perception. I don't know what Gibson would have thought of the computer/computational model-type which I think is your basic model. I'm not sure even to what extent such model-types were being developed at the time Gibson died. (I think he died in the mid- to late-'70s.) Edelman believes that the computer/computational model-type is just wrong, and I find his arguments on that score persuasive. (He after all is a neuroscientist who is well informed of the details of current knowledge of neuro-anatomy and physiology.)

The one issue pertaining to visual perception on which I think you and I do agree (if I'm now correctly understanding your approach) is that seeing is the whole process, that no "picture" of the world is formed which is being "looked at" internally. However, I think that our respective ideas of the details of what occurs are different enough, we have significantly different theories.

I'll leave off there until after Thanksgiving. I haven't time now to try to explicate my own views.

Ellen

___

[Ellen Stuttle]

A brief follow-up thought (to my long post #260) pertaining to the total non-significance of the retinal image to visual perception: What happens is more like a visual experience of the firing of the cannons in "The 1812 Overture." (I suppose that I thought of the comparison because it seemed to be something which Dragonfly, with his musical knowledge, would understand. The issue is much more one of the timing of bursts of neuronal firing than it is one of literal spatiality, though the distribution of the firings is important, but not in the sense of an "image" being translated from 2-dimensional to 3-dimensional.)

I hope that will help in understanding how I ... well, in a sense ... "visualize"... or "conceptualize" ... the visual process.

Ellen

___

Edited October 9, 2006 by Ellen Stuttle

[reason.on]

I think that what the brain does is better described as interpreting spatio-temporal arrays of input with the assist of memory processing so as to enable us to perceive as a continuous scene discontinuous impulses triggered by the structural patterns of photons being absorbed by the retina.

Now that sentence is a mouthful. I don't swear that I'll stick with the exact wording of it. But it expresses my current understanding of how visual perception works. It's a sentence which combines Gerald Edelman's theories of brain functioning with J. J. Gibson's theories of perception. I don't know what Gibson would have thought of the computer/computational model-type which I think is your basic model. I'm not sure even to what extent such model-types were being developed at the time Gibson died. (I think he died in the mid- to late-'70s.) Edelman believes that the computer/computational model-type is just wrong, and I find his arguments on that score persuasive. (He after all is a neuroscientist who is well informed of the details of current knowledge of neuro-anatomy and physiology.)

For anyone interested, here are few examples of both Edelman and Gibson's thoughts on the matters ES presents above...

Naturalizing consciousness: A theoretical framework

Gerald M. Edelman Neurosciences Institute, San Diego, CA 92121

Contributed by Gerald M. Edelman, March 7, 2003

According to the framework proposed here (Fig. 2), consciousness arises as a result of integration of many inputs by reentrant interactions in the dynamic core. This integration occurs in periods of <500 ms. Selection occurs among a set of circuits in the core repertoire; given their degeneracy, a number of different circuits can carry out similar functions. As a result of the continual interplay of signals from the environment, the body, and the brain itself, each integrated core state is succeeded by yet another and differentiated neural state in the core. This capability confers an evolutionary advantage on individuals possessing it, for, by these means, richly structured events can be related adaptively to the past history of value-dependent learning events in an individual animal.

The sequences and conjoined arrays of qualia entailed by this neural activity are the higher-order discriminations that such neural events make possible. Underlying each quale are distinct neuroanatomical structures and neural dynamics that together account for the specific and distinctive phenomenal property of that quale. Qualia thus reflect the causal sequences of the underlying metastable neural states of the complex dynamic core. The relationship of entailment between these neural states and the corresponding states of consciousness has the property of fidelity. Given the hyperastronomical functional connectivity patterns of the dynamic core, however, no two subjects can have identical core activity. This is consistent with the TNGS, which views the brain as a selectional system in which myriad neural states provide degenerate repertoires for matching a rich array of signals. Degenerate patterns (24) in the reentrant dynamic core provide an adaptive system for dealing with the enormously complex combinations of such signals.

The qualia that constitute these discriminations are rich and subtle. The fact that it is only by having a phenotype capable of giving rise to those qualia that their "quality" can be experienced is not an embarrassment to a scientific theory of consciousness. Looked at in this way, the so-called hard problem is ill posed, for it seems to be framed in the expectation that, for an observer, a theoretical construct can lead by description to the experiencing of the phenomenal quality being described. If the phenomenal part of conscious experience that constitutes its entailed distinctions is irreducible, so is the fact that physics has not explained why there is something rather than nothing. Physics is not hindered by this ontological limit nor should the scientific understanding of consciousness be hindered by the privacy of phenomenal experience. At the end of our studies, when we have grasped its mechanisms in greater detail, consciousness will lose its mystery (4, 25) and be generally accepted as part of the natural order.

The Purple Perils (unpublished manuscripts of J.J. Gibson)

The Relation Between Retinal Stimulation and Visual Sensation

The theory (a) that sense impressions are the basis of perception and that an inventory of these impressions is possible, the supposed law (b) that sense impressions are specific to particular afferent neurons or (nowadays) receptive units, and the assumption © that a visual stimulus is analogous to a prod applied to one of the receptors or receptive units of the retina, albeit by light, in the way a sharp point is applied to the skin (the retinal image being a pattern of such stimuli) ñ these assumptions have led to a set of psychophysical expectations about vision. That is, experimenters will expect that certain corresponding variables of the stimulus applied to the retina will yield certain corresponding variables of the sense impression.

These expectations can be listed. (1) The intensity of a stimulus, either a spot or a patch, is supposed to determine a sensation of brightness. (2) The wavelength of a stimulus is supposed to determine a sensation of hue. (3) The "purity" of the wavelength-composition is supposed to determine saturation. (4) The location of the stimulus on the retina is supposed to yield a sort of sensation of location, the "local sign." (5) The form of a luminous patch is supposed to yield a sensation of "extensity." (7) The beginning and the end of stimulation (if abrupt) are supposed to yield sensations of "on" and "off," and a pulse of stimulation is supposed to yield a flash of brightness. (8) The duration of the stimulus is supposed to yield a sensation of duration (propensity). (9) The motion of a stimulus over the retina is supposed to yield a sensation of motion, and then velocity a sensation of velocity (the "retinal image displacement" hypothesis, Gibson, 1968).

Not one of these expectations has been borne out in simple form during a century of psychophysical research. There is no correspondence of brightness to intensity except in the night sky or under wholly artificial conditions. The same is true of hue and saturation except when a spectroscope is used. There is no impression of stimulus location on the stationary retina (as there is on the stationary skin) and not even an impression of external location when a point-source of light is projected on the retina in complete darkness (this being the significance of the so-called "autokinetic" phenomenon). There is no correspondence between an external pictorial form and the phenomenal form when the picture is slanted; there are only the puzzling anomalies of the tendency to "form constancy." The sensation of extensity, or "retinal size," is a myth; therefore the experience of object-size cannot be reduced to retinal size however hard experimenters try to do so. (This explains why experiments on the size of the moon in the sky are unrevealing: it is nonsense to ask an observer about the experienced object-size of the moon.)

The last three of the listed expectations have to do with temporal variation. Perhaps there are sensations of abrupt "on" and "off," but psychophysical correspondence is spoiled by the interaction between time and intensity, and by the "fusion" of successive pulses of light. Attempts to link physical duration with phenomenal duration, the "time sense," have not been convincing and the experiments are full of anomalies. Lastly, the supposed correspondence between the notion and velocity of a stimulus on the retina and sensations of notion and velocity simply does not exist. Efforts to discover it by treating the retina as if it were the skin have failed. The supposed correspondence is violated every time the eye moves (Gibson, 1968).

What are the implications? If simple and reliable correspondences cannot be established between "proximal" retinal stimuli and visual sensations there seem to be two alternatives for the theory of sense perception. One can cling to the assumptions stated above in the first paragraph and suppose that sense impressions would correspond to stimuli except for the intervention of a process of sensory organization ñ a process that explains not only the puzzling interactions among sense impressions but also the formation of percepts. This is the road of Gestalt theory. It partly accepts and partly rejects the expectations of sensory psychophysics (what Koffka called the "constancy hypothesis"). The other alternative, more radical, is to question the generality of all three of the primary assumptions, to suppose that the results of psychophysical experiments applying stimuli to a stationary retina are irrelevant to perception, and to begin the study of perception as an autonomous subject based on ecological optics and the notion of stimulus information.

An Insoluble Puzzle of Epistemology

Sensation-based theories of perception seem to face a dilemma which can be stated in the following way: Is it the senses that are to be trusted and ideas not? Or is it only ideas that can be trusted and the senses not? All previous theories of what is ordinarily called sense perception take for granted that separate contributions are made to perception by sensations and ideas, an objective contribution and a subjective contribution, one coming from outside and one from inside. If so, is it the objective contribution that makes perception veridical and adaptive and the subjective contribution that makes it distorted and susceptible to illusion? Or is it the other way round, the objective contribution (concepts or accumulated past experience) makes it adequate and trustworthy?

It seems to me that no theory of perception, either any old or new form of empiricism on the one hand, or any form of rationalism, nativism, or Gestalt theory on the other, has been able to resolve this perplexity. Even Piaget who attempts in The Mechanisms of Perception to combine what he considers to be the best features of all these theories is forced in the end to conclude that the objectivity of perception depends on the subjective contribution, that is to say on concepts. This seems to expose the contradiction.

The only solution, I suggest, is to reject the sensation-based theories of perception with their underlying assumption of separate contributions from the external object and the perceiving subject. Perception is of the object (environment) by a subject (observer). These sources of available information are not cognate and the information picked up is not combined or mixed. There is direct perception of the world accompanied by direct proprioception of the self. Errors, of course, can occur for both, but that is another matter.

This suggests, in the last analysis, that both the perceiving and the remembering of the environment are modes of apprehending it, i.e. that they cannot be dichotomized. Hence percepts are not mixtures of sensations and memories and, equally, memories are not the rearousal of "old" percepts. Apprehension is not "time-binding" in the sense that the past is stored, but "time-free" in the sense that what does not change is perceived along with what does change. The radical implications of this hypothesis remain to be worked out.

The Puzzle of Optical Structure

What is an optical array? Should it be treated as a distribution of different luminous intensities (stimuli) or as a topological map of different areas (patches)? It certainly is not a stimulus; is it then a pattern of stimuli, or is it a map? A distribution is analyzed in terms of energies; a map is defined in terms of contours. Intensities vary continuously but contours are discontinuous. Intensities imply corresponding point-sensations of brightness; the map implies only impressions of contour or "contrast." The lower-level analysis suggests that perception is based on sensations; the higher-level description does not suggest this, since sensations are changing all the time . It suggests that perception is based on invariants.

We need to be able to talk about an optic array at a point of observation whether or not an eye is stationed at that point. If no eye is there, no stimulation occurs; but information is available there (and even more information if the point moves). How do we describe this information? What is the structure of the array, especially its invariant structure? Is it to be treated as a distribution of energies or as a topological map?

The issue becomes evident in the phenomenon of Mach bands. If we ask what this phenomenon means for the perception of the environment, instead of treating it as a problem for visual physiology (Ratliffe, 1965), a deep puzzle must be faced. In the case of an array in which a Mach band appears, there is no step of intensity, no jump in the distribution and thus no contour in the array; and yet a contour is seen! This puzzle has led sensationists to suppose that somehow a contour in the array is "accentuated" by physiological interaction in the nervous system. But this reasoning will not do, for a contour cannot be accentuated if there was none there to begin with. The sensationist ought to conclude that a contour is created by the nervous system where none exists in the array. But this would also be unsatisfactory, for psychophysics teaches that no experience is created without a stimulus correlate. Is there a contour in the array or is there not?

My tentative solution to this puzzle is to suppose that a discontinuity in the array exists and that it is perceived as a discontinuity of the environment. The discontinuity in the array need not be a jump or step of intensity; it can be one of several kinds. As we now know, there can arise "anomalous" contours in perception without there being any ordinary contours at all in the array. The effort to explain the Mach band in terms of a point of inflection on the curve of the intensity distribution, or in terms of a high second derivative of the function, is to be understood as a sort of halfway effort in this direction.

A discontinuity in the array is an "objective" fact, not a creation of the nervous system, or of the mind. It may not be amenable to analytical geometry and calculus, inasmuch as these disciplines presuppose continuity; but that does not prove it is subjective. The environment is sliced up by all sorts of discontinuities (even if the world of physics and mathematics is not) and it is a great mistake to think that these cuts and splits are imposed on the world by the act of perception. We have too long supposed that the physical world is continuous (or at least very fine-grained) and that hence the light to the eye is continuous or fine-grained, concluding from this that the discontinuities in perception are a "subjective contribution." But ecological physics and ecological optics do not make this mistake.

The deep question is not whether Mach bands are subjective or objective but whether contours are subjective or objective. The problem is whether optical structure, more generally "form," is a contribution of the mind or a fact of the world, and my solution to this problem is ultimately to assert that it is a false problem. It is false because the objective-subjective dichotomy is false. The basic fact of ecological optics, the ambient optic array at a point, is neither "objective" nor "subjective" since it escapes the objective-subjective dichotomy. It implies both the environment and a potential observer, both the world and the possibility of observing it. It assumes a logical reciprocity of animal and environment, not a dualism of the phenomenal and the physical, nor a correspondence between the phenomenal and the physical. To perceive something is not to have a thing called a "percept" of it, and to be conscious of something is not to have a consciousness-copy of it. To perceive is simply to perceive.

The ambient light rays coming to a "point sink" in space can be represented as a distribution of intensities that make a closed surface, i.e., a sort of "lumpy bag." The ambient optic array at a point of observation in an illuminated environment can be represented as a set of nested visual solid angles with a common apex having a reflecting surface as its base. Which representation is more appropriate for the study of perception? Are there intermediate representations that would be appropriate for certain problems of vision? I favor the "ecological" representation, but it's not the only possible one. It does, surely, have the virtue of emphasizing discontinuities, and suggesting problems like the perception of occluding edges. It presupposes a steady state of reverberating light in the medium. It abandons certain classical problems of sensory physiology, but it embraces certain other problems that have either been neglected or treated in terms of a vague and speculative mentalism.

RCR

[Dragonfly]

Ellen, I just don't have the time to answer all the points in your long post. I think most problems arise while you interpret terms in a different sense than I intended, like the term "projection". I think it was obvious that I didn't mean some physical, spatial projection, but the psychological illusion, for example that the pain "is" in the finger (we feel it is there, but that is an illusion: whatever is wrong with the finger, the pain is in the brain (it is generated in the thalamus), just disconnect the appropriate nerve and the pain will vanish completely, whatever happens to your finger). Another example is the term "mapping"; you seem to think I use that in the sense of a geographical mapping, while I mean it in the more general, mathematical sense, which in my opinion not different from your viewpoint. Further the word "perception" may be used in different ways, in the general, loose sense we may say that we perceive a part of the world around us, but that is a shortcut for describing an intricate process in the brain, which may be appropriate if the perception (as a process in our brain) is more or less accurate. But what we "perceive" is not always correct, and then we don't perceive reality, but something that doesn't really exist. I think that the intended meaning will be clear from the context, so that we don't have to qualify our all our statements continuously.

Instead, I think that to consider the retinal image relevant at all to seeing is seriously mistaken, a point to which I'll return.

Well, of course the retinal image is relevant to seeing, without it there wouldn't be any vision at all! It is the input for our visual system. Now no matter how this image is digitized and processed in the brain in terms of the timing and distribution of neuron firings, it is the information in that 2-dimensional image that is used to construct a 3-dimensional model of the world. (BTW, I'm not such a big fan of Tchaikovsky, although his ballet music is nice.)

[Michael Stuart Kelly]

Dragonfly,

I have been following all this with interest, but stepped back for a while. There is one issue, however that has caused me a considerable itch - this business about where pain occurs. Aren't t all the parts necessary for pain to occur? Isn't pain a perception involving brain, nerves and finger?

You said:

I think it was obvious that I didn't mean some physical, spatial projection, but the psychological illusion, for example that the pain "is" in the finger (we feel it is there, but that is an illusion: whatever is wrong with the finger, the pain is in the brain (it is generated in the thalamus), just disconnect the appropriate nerve and the pain will vanish completely, whatever happens to your finger).

If you disconnect the appropriate nerve, doesn't the pain vanish in the brain also?

Rather than say perception of pain is in the finger or in the brain, wouldn't it be more useful to say something more like the following? Part A of the pain is in the finger, Part B is in the nerve pathways, Part C is in the brain, etc., and if you remove any of these elements, the perception of pain goes away.

(I would consider perception of pain for a member that no longer exists a malfunction of the brain, not actual pain perception, just as I would consider hypersensitivity in a finger a malfunction of the nerves.)

Michael

[Dragonfly]

I have been following all this with interest, but stepped back for a while. There is one issue, however that has caused me a considerable itch - this business about where pain occurs. Aren't t all the parts necessary for pain to occur? Isn't pain a perception involving brain, nerves and finger?

It's true that all these parts are necessary for the pain to occur, but that doesn't imply that the pain is distributed over all these parts. If we make a picture of the moon we don't say that the picture is on the moon (well, unless it's taken by an astronaut there, but that is not what I mean), although it is a picture of the moon, which wouldn't exist if the moon weren't there.

If you disconnect the appropriate nerve, doesn't the pain vanish in the brain also?

That was exactly my point.

Rather than say perception of pain is in the finger or in the brain, wouldn't it be more useful to say something more like the following? Part A of the pain is in the finger, Part B is in the nerve pathways, Part C is in the brain, etc., and if you remove any of these elements, the perception of pain goes away.

You might say that, although I think it is a less satisfactory way of describing the situation. My point is rather that if you want to localize pain at just one part of the chain, you should distinguish between the subjective experience (it's in the finger) and the objective description (the experience, the qualia if you want, is generated in the brain), just as we say (at least as I would say) that the perception of the moon if I look at it is in my brain and not on the moon or in the photons coming from the moon.

(I would consider perception of pain for a member that no longer exists a malfunction of the brain, not actual pain perception, just as I would consider hypersensitivity in a finger a malfunction of the nerves.)

Well, I suspect that people who experience such pain would disagree that it is not an actual pain perception, for them it is no less real than that of pain "in" a real member. They would probably not be pleased if you told them that they didn't have real pain. The cause may not be the usual one, but that doesn't make the perception less real - a real perception is not necessarily the same as a perception of something that is real.

[Michael Stuart Kelly]

Dragonfly,

Two points:

My point is rather that if you want to localize pain at just one part of the chain...

My question is why would anyone want to do that? You need all of it for the pain to exist. Saying that the sensation came from contact by the finger with something is no illusion, nor is the identification by the brain of where the contact is located.

Do it the other way - pleasure. Can we have sex without genitals and without a brain? We need them both. When orgasm comes (for a male), you might say it is in the brain, but the ejaculation is in the penis. So there is physical evidence. The experience is in both places and cannot exist without either.

This is what I think is meant by mind-body integration.

On the last point:

Well, I suspect that people who experience such pain would disagree that it is not an actual pain perception, for them it is no less real than that of pain "in" a real member. They would probably not be pleased if you told them that they didn't have real pain. The cause may not be the usual one, but that doesn't make the perception less real - a real perception is not necessarily the same as a perception of something that is real.

A malfunction is a malfunction. That does not make it less (or more) intense. People with psychosomatic illnesses have real symptoms all the time. That does not put that experience into the same category as an actual organic cell degenerative disease.

With my drug experiences, I have experienced acute paranoia - the heart-pounding, cold-sweating terror type paranoia. I would not put that into the same category with my normal fear mechanism. It was a malfunction due to overriding chemical influences, not experiential influences that the mechanism was evolved to deal with. When those chemical agents were expelled, the malfunction stopped.

We do not identify the characteristics of a healthy organism (or healthy part of an organism) by the malfunctions.

Pain perception is one such mechanism. The pharmaceuticals industry has many, many studies on pain and has been very successful in designing drugs to alleviate it by interfering with one point or another along the "pain chain". This is why I repeat that it is a whole thing that ceases to exist if all the parts are not present.

Michael

[Dragonfly]

Michael, I think this discussion has become a question of semantics and definitions, which may sometimes be useful, but which isn't really interesting to me. I think that my definitions are more logical than yours, but if you want to use different definitions you're of course free to do so. The only important thing is that clearly is understood what is meant. I'm afraid that a lot of philosophical discussions and disagreements boil down to a different use or interpretation of certain terms, as if only one single "true" meaning of these is possible.

[Ellen Stuttle]

Dragonfly, I think you're right that in part the discrepancies in our views result from different interpretations of terminology. However, I do think that there's a more basic problem of differing underlying theoretic approaches, and I think that your idea that the "retinal image" is translated into a 3-d model is significant to the difference.

In response to my writing "Instead, I think that to consider the retinal image relevant at all to seeing is seriously mistaken, a point to which I'll return," you replied (post #263):

Well, of course the retinal image is relevant to seeing, without it there wouldn't be any vision at all! It is the input for our visual system. Now no matter how this image is digitized and processed in the brain in terms of the timing and distribution of neuron firings, it is the information in that 2-dimensional image that is used to construct a 3-dimensional model of the world.

Let me first explain again what I mean by "the retinal image," attempting to avoid further terminological misunderstanding. What I'm talking about is that the retina, from the perspective of someone looking at the retina (either a dissected prepared retina or an in vivo retina viewed with appropriate opthamological equipment), is like a photographic film; an image can be seen on it. This fact led in the history of psychophysics to thinking of the retina as responding in a way analogous to points on the skin responding to pin pricks, and thus to many, many attempts at correlating a lay-out of retinal points with the phenemona of vision. As Gibson writes in one of the excerpts RCR posted (post #262):

The theory (a) that sense impressions are the basis of perception and that an inventory of these impressions is possible, the supposed law (b ) that sense impressions are specific to particular afferent neurons or (nowadays) receptive units, and the assumption (c ) that a visual stimulus is analogous to a prod applied to one of the receptors or receptive units of the retina, albeit by light, in the way a sharp point is applied to the skin (the retinal image being a pattern of such stimuli) -- these assumptions have led to a set of psychophysical expectations about vision.

He goes on to list resultant expectations, and then writes (and explicates) that: "Not one of these expectations has been borne out in simple form during a century of psychophysical research."

At some point if you have the time, I recommend reading the material from Gibson which RCR provided. It talks at length about features of what I tried to summarize in a mouthful of a sentence in post #261.

Re Tchaikovsky, you wrote: "(BTW, I'm not such a big fan of Tchaikovsky, although his ballet music is nice.)"

Basically the same feeling here, "btw."

--

RCR: THANK YOU! Having those excerpts easily available will save me a lot of time if I can return to this subject after Thanksgiving. As usual, your google talents are a boon. ;-)

Ellen

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Edited October 11, 2006 by Ellen Stuttle

[reason.on]

RCR: THANK YOU! Having those excerpts easily available will save me a lot of time if I can return to this subject after Thanksgiving. As usual, your google talents are a boon. ;-)

My pleasure, of course. I've just stumbled upon another short piece from *The Purple Perils* (Gibson's unpublished work), that might add in clarifying further part of the distinction you are trying to make..

Note on the "Topography" of the Visual Stimulus

F. Klix has just written a book on the psychophysics of space perception, partly based on the 1950 hypothesis that the terrestrial environment is mapped into the retinal image as gradients of size, density, spacing, proportion, and the like. The "topography" of the stimulus, he suggests, is crucial, for it is related to the topography of the world by rules of transformation known to geometers.

This program for a psychophysics of space perception will undoubtedly be pushed to its limits, both at Cornell and elsewhere. What are its limitations, if any? Promising as it is, I do not see how it can handle all those types of perception involving sequential stimulation. Some of these are (1) the perception of the surrounding world by head and eye turning, (2) the perception resulting from (and controlling) locomotion, and (3) the perception of external events.

Topography is the accurate description of a permanent terrain by map-making. By analogy, stimulus topography could apply to a sort of frozen stimulus. Ultimately, the available energy for arousing vision is not completely analyzable as a map, or by the operation of mapping. For a complete analysis we shall have to consider (1) the spherical array of ambient light, (2) the continuous change in the projection of light to a non-stationary point, and (3) the continuous transformation of a "figure" without motion of the "ground". Even if "topography" were adequate for the description of ambient light, accordingly, it would still be necessary to analyze changes in stimulus topography, one type being (2) propriospecific and the other being (3) exterospecific.

A projective transformation, that is a mapping of one surface on another or a correspondence between one form and another should not be confused with a sequence-transformation, that is, a transmutation, a change, or "motion", or continuous process. These two have an entirely different status for stimulus-geometry. the first is a relation between object and stimulus; the second is a enduring stimulus in its own right. I have not been clear about this distinction in the past.

Consider the effect of Kohler-spectacles on perception; they cause a projective transformation of the entering array relative to the ambient array. But they also cause a visible sequence - transformation (an elastic deformation) of the phenomenal world when the head is moved. Adaptation to such spectacles is not simply a matter or "remapping" the picture delivered by the retinal image, but something much more comprehensive. The problem of space perceptions includes not only the question of how we see the correct arrangement of things but also how we see the rigidity of this layout during exploration and locomotion.

There is also the following, which outlines and constrasts, step-by-step, classical theories of vision with Gibson's more radical views, most interesting is the final point:

Contrasting Assumptions of (A) the Classical Theory of Vision and (B) a New Theory of Vision

X,A. The brain (or the mind) performs operations on these data of sense, the kind of operation assumed depending on the theory of perception adopted. A minimal list of such operations follows.

1. The gap in the sensory image caused by the retinal blind spot is "filled in".

2. The sensory image from the right eye is "fused" with that from the left eye to produce single vision, but when the two images do not exactly coincide the disparity is experiences as double imagery.

3. The half of each sensory image in one hemisphere of the brain is combined with its other half in the other hemisphere.

4. The displacement of the sensory image in the brain caused by an eye movement is canceled so that the phenomenal object does not move (or perhaps the local signs of each sensation are shifted by the amount of the eye movement).

5. The series of temporary sensory images caused when the animal turns around is converted by memory into a simultaneous composite image of the surroundings.

6. The expansion of the sensory image caused when the animal approaches an object (or vice versa) is compensated so that the object does not seem to get larger.

7. The rotation of the sensory image caused when the animal inclines its head to right or left is compensated so that the object does not seem to tilt.

8. The sensations of brightness and color composing the sensory image are transformed so as to correspond not to the amplitude and wavelength of the energy-points in the retinal image but approximately to the reflectance and pigmentation of the surfaces of the object.

9. The third dimension of depth (or distance) is added to the sensory image, perhaps by memories of touch becoming associated with sensations of vision (Berkeley), or by unconscious interpretation of visual cues (Helmholtz) or by spontaneous self-distribution of brain processes (Koffka) or by innate categories of mind (Kant).

10. In particular, the size of the sensory image is compensated so as not correspond to the angular size of the retinal image but approximately to the physical size of the object.

11. The form of the sensory image is transformed so as to correspond to the appearance of the object viewed from in front instead of the foreshortened appearance when viewed at a slant.

12. The sensory image of the front side of an object is supplemented by memory images of its back side, and the perception of the hidden background of an object is provided either by memory images or by the spontaneous segregation of ground and figure in the brain. The impermanent images are thus converted into a conception of permanent objects in a fixed layout.

X, B. The brain is the highest controlling center of the nervous system but it is not the organ of the mind nor the theater of consciousness. It does not perform operations on the data of sense, or view sensory images, or store and retrieve memory images, although it controls the visual system.

1.The gap of hole in the sensory image is an artifact of monocular eye-fixation. The optic array is perfectly continuous.

2.Single vision from two eyes is a false problem. If two images in the brain do not exist, they do not have to be combined.

3.If half-images in the two hemispheres do not exist, they do not have to be combined.

4.If the physiological image in the striate cortex is myth, it is not something whose displacement with eye movement has to be canceled.

5.If the visual system samples the ambient light the sequence does not have to be converted into a single pictorial scene. Awareness of the surroundings is not pictorial to begin with.

6.The incidental impression of an expanding scene during approach to an object is one symptom of locomotion (visual proprioception); the expansion of the figure of an object with increased covering of the background and without expansion of the array is information for an approaching object.

7.The incidental (usually unnoticed) rotation of the scene when one inclines his head is also visual proprioception; the rotation of a figure relative to the array, however, is information for a tilting object.

8.The information for the reflectance and pigmentation of any part-surface in the world is given by the discontinuities (transitions, contrasts) in the extended optic array from a layout of surfaces. Sensations of brightness and hue corresponding to amplitude and wavelength of radiation are either artifacts of "reduction-viewing" or are perception of the luminosity of radiating sources of light as such).

9.The third dimension of empty space as such is not specified for vision. The layout of surfaces in the environment, however (the dihedral angles, convexities, concavities, and occluding edges of one thing in front of another) is specified by the structure of contrasts in the ambient array that is invariant with change of position of change of illumination.

10.The size of an object is usually specified along with its distance in a natural optic array. The size is given by the amount of ground-texture its figure intercepts, and the distance along the ground by the place (in the here-to-horizon gradients) where the figure intercepts the ground. But there is no reason to suppose that a sensory image of size is enlarged in proportion with sensory impressions of a distance.

11.The form of the edges of a surface is specific in a natural optic array along with its slant relative to adjourning surfaces (dihedral angles and edges) by relative gradients. The rigid form is given by the invariants under perspective transformations. The perspective (pictorial) form is an incidental sensation that is seldom noticed in the detecting of slant-layout. There is no need to suppose that a pictorial impression of foreshortened shape is converted into another pictorial impression of frontal shape by a reciprocal impression of slant.

12.Animals and children are not aware of the pictorial impression of the front side of each object in the world. They do not notice at first its perspective size of form, nor do they notice the invisibility of its back side, not do they pay attention to the invisibility of an occluded surface behind it. They are interested in the invariant distinguishing features of objects instead. They are also concerned with permanent layout. The optical covering and uncovering of background by edges (and the simultaneous differential amounts of covering and uncovering of background in the two eyes) provides information for the perception of hidden surfaces. There is therefore no need to suppose that sensory images have to be supplemented by memory images in order to explain the phenomenal permanence of the environment.

RCR

Edited October 11, 2006 by R. Christian Ross

[reason.on]

One more relevent excerpt from *The Purple Perils*...

In sense physiology, the excitation of a receptor by stimulus energy is nowadays said to carry information about the environment. This information is said to be conveyed to the central nervous system and then it is supposed to arouse a sensation, the sensation being specific to the receptor stimulated. But the input can only "carry information" to the extent (1) that each receptor is specialized to receive one and only one kind of energy, and (2) that each receptor transduces or translates the intensity, frequency, or other quality of the stimulus into nervous impulses in a specific way, that is, only to the extent that the is "psychophysical correspondence" between stimulation and sensation.

Even if this orthodox formula were correct, the information carried to the central nervous system would only be such as to specify the stimulus environment, not the environment of objects and events that are sources of stimuli. Only the pattern and flux of the sea on ambient energy in which the animal lives would be specified, not the pattern and change of the surrounding substances and surfaces of his environment. He would detect the proximal stimuli only, and they are notoriously poor indicators of the environment proper. The environment of stimulation, which includes self-produced or obtained stimulation as well as imposed stimulation, should not be confused with the environment that stands behind stimulation and makes it possible. But physiologists do not usually realize this fact, lumping everything together under the term physical environment.

But even the orthodox formula of sense physiology is inadequate. It is beginning to appear that receptors are not highly specialized to receive one and only one kind of energy, and that each receptor does not simply translate the physical variables of stimulus energy into corresponding variables of nervous impulses. If so, nervous inputs to the brain cannot be said even to carry information about stimuli," let alone information about the environment.

In the face of this situation, sensory physiologists are (reluctantly) appealing to vague concepts like patterns of stimuli and are otherwise casting around for new explanations. The question arises whether it would be more useful for them to discard the whole theory of discrete stimuli, discrete receptors, one-way sensory inputs, and central "sensations" instead of trying to salvage it and reconcile it with the facts of information-pickup. They should consider the logical possibility that information about the environment cannot possibly be transmitted along a nerve; then they can begin to think about ways in which a perceptual system might work.

The kind of information necessary for perception is simply not comparable to the kind of information that can be transmitted as messages from a sender to a receiver. It is true that nerve impulses are necessary for the activity of perception, along with adjustable organs and nerve centers, but the fibers run in both afferent and efferent directions. It is true that cutting a nerve stops nerve activity. But this does not imply the doctrine of sensory messages transmitted to the brain by way of the sensory nerves, along with its embarrassing corollaries of a sensorium, a seat of consciousness, a storehouse of memories, and so on. The activity of perception is not localized at any point in the circular process, nor is it terminated in any part of the nervous system.

RCR

[Dragonfly]

Let me first explain again what I mean by "the retinal image," attempting to avoid further terminological misunderstanding. What I'm talking about is that the retina, from the perspective of someone looking at the retina (either a dissected prepared retina or an in vivo retina viewed with appropriate opthamological equipment), is like a photographic film; an image can be seen on it. This fact led in the history of psychophysics to thinking of the retina as responding in a way analogous to points on the skin responding to pin pricks, and thus to many, many attempts at correlating a lay-out of retinal points with the phenemona of vision.

The retinal image is simply the pattern of the photons that strike it, which does exist whether someone else looks at it or not. And it is of course essential to seeing. People use spectacles to create a sharp image on the retina when this is no longer possible by natural means, due to errors in focus and astigmatism. You can't get a driving license if the image is not sharp enough, as you in that case are deemed not to be able to interact in an appropriate manner with your environment, creating an unnecessary danger on the road. This retinal image is the input for your visual system, that is an incontrovertible fact. Gibson's ramblings are not relevant, you may discuss different theories about how exactly the information contained in the retinal image is processed in the brain to create the visual perception, but there isn't any doubt that information contained in the retinal image is processed in the brain to create the visual perception.

[Ellen Stuttle]

Prefatory typographical query:

A number of months ago, Dragonfly told me some code which works on the Mac for writing an umlauted o, but I've forgotten the code, and misplaced the post (which I'd copied and filed...somewhere). I'd appreciate re-instruction; also instruction on how to code an umlauted u.

Ellen

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[Ellen Stuttle]

Sometimes a subject gets hold of my thoughts no matter how inconveniently. Yesterday, after I sent my post #267, I was still thinking about the idea of the retinal image as being key to the visual perceptual process, and I recalled that there's a good discussion of how that idea assumed importance in Edwin G. Boring's classic A History of Experimental Psychology. So I got out my copy of Boring and re-read part of that discussion, and of some other sections, too. Since the material is useful background for debates here, I decided to type part of it. All quotes are from the Second Edition, copyright 1950 by Appleton-Century-Crofts, Inc. (Copyright © renewed, 1957, by Edwin G. Boring; the First Edition appeared in 1929, Copyright The Century Co.)

As indicated in a prefatory post, I don't know how to code umlauts. Muller is correctly spelled with an umlauted u, and Handworterbuch with an umlauted o.

[i've inserted some extra paragraph breaks in hopes of rendering the main outlines easier to follow.]

In this period [approximately 1800-1850], almost every account of vision concerns itself primarily with the physics of the stimulus, the anatomy of the eye, and consequently the relation between these two subjects--that is to say, with the eye as an optical instrument. [Charles] Bell's [and brother's, whose first name isn't given] [1803] account is typical [the account referenced is in the third volume of The Anatomy of the Human Body], but the emphasis had shifted only a little thirty-five years later with Johannes Muller [in his Handbuch der Physiologie des Menschen (1833-1840), the publication of which Boring describes as of "tremendous importance" (pg. 98)].

Of the stimulus, beside the general fact that it is normally light, we are told of colors produced by refraction, by reflection, by transmission and by interference. All the essential structures of the human eye were known except the variability of the curvature of the lens. The comparative anatomy of the eye was studied for its own sake, but also because it seemed as if a knowledge of simple vision in subvertebrate forms would lead to a recognition of the more important elements in vertebrate vision. [This was pre-Darwin; the comparative work wasn't couched in terms of Darwinian theory.]

Starting with physics and the stimulus, the progress of knowledge was from without in. Thus a knowledge of the eye as an optical system, which results in the formation of an image on the retina, was the all-important problem.

Bell (1803) treated it in detail. Treviranus (1828) was primarily concerned with it. Muller (1838) made it the primary problem, dealing with refraction by the lens and other media, the achromatic character of the system, and the defects of the system in myopia and presbyopia and their correction by lenses. In Wagner's Handworterbuch, beside Volkmann's section on sight (1846) there is a section by Listing on dioptrics (1853), which contains the principle of the reduced eye and Listing's law of the relation of the image to the curvature of the retina and to torsion of eyes in movement. The problem by this time had been extended to binocular vision and eye-movement. [The next two sentences look ahead to the next period in psychophysics.] Such was the setting upon which Helmholtz's classical analysis of physiological optics (1866) supervened. Wundt (1862) and Hering (1868) dealt with the same problem. It was at first the fundamental problem of vision.

The facts were fundamental, partly because the doctrine of the specific energies of nerves raised the question of the mechanism of perception. [A section on "specific energies" follows this excerpt.] If we put the matter at the philosophically unsophisticated level of Johannes Muller, we shall only be presenting the problem as the physiologists of his day saw it. The common view was that perception consisted in the transmission, in some way or other, by the nerves to the brain of properties emanating from perceived objects. Muller argued that we perceive directly not the properties of objects, but the properties of the nerves themselves. How, then, did we come to know about objects correctly? Because the state of the nerves corresponds to the state of objects in ways that can be formulated under certain definite laws.

Now this means [Muller argued] that we perceive by sight, not an object nor even the light from it, but the state of the optic nerve and of the retina which is but the extension of the optic nerve. Aside from color, the most obvious thing about visual perception is that it yields correct information about space, size, shape and position. This fact comes about because the eye as an optical instrument projects an image of the perceived object upon the retina, an image that is as correct a copy of the object as a bidimensional picture could be. It seemed to Muller and other physiologists, therefore, that, by showing how the image on the retina resembles the object, one comes near to explaining perception. If the excitation on the nerve is a pattern, and the sensorium perceives directly the state of the optic nerve, no wonder then that it perceives a pattern; and, if this pattern is the optical image of an object, no wonder that it perceives it correctly.

Muller was also, of course, quite clear that the retina would thus at times misrepresent external space. All the arguments for specific energies that are dependent on 'inadequate' stimulation of the retina show that illusion is possible, that the sensorium is not always correctly informed. The size of the visual field [again, this is Muller's argument] is simply the size of the retina, for it is the retina that the sensorium perceives directly. Absolute size is thus dependent upon the size of the retinal image--that is to say, upon the visual angle and not upon the size of the object. The perception of direction depends upon the point of the retina stimulated, both relatively and absolutely.

The image on the retina is inverted, but Muller saw no problem as to why we do not see things upside down. [There were others who did see a problem; as I've said before, the issue of the inverted image raised some consternation.] It was plain to him that there is no meaning to 'up' except the sensation that results from the excitation of the bottom of the retina, and that only a man with a knowledge of physiological optics would ever, in directly perceiving his retina, know that this sensation actually came from the bottom of the retina. There is here in Muller the hint that one learns 'up' from 'down' by experience.

In general, Muller remains good doctrine today [so Boring said in 1950; just how "good" the "doctrine" was, others were already questioning], although [boring continues] we know that perceived size is neither entirely relative nor entirely proportional to visual angle [and see other problems indicated in the excerpts from Gibson in post #262].

It is plain that, for Muller, the theory of vision is merely the theory of the excitation of the retina by the optical image (my emphasis).

--

The idea of "specific nerve energies" is the idea that each sensory modality has a particular kind of nerve fiber. Here's a little of the early history on this (the history becomes highly complicated as it proceeds).

Johannes Muller in 1826 argued for five kinds [of sensory fibers], one for each of the five senses, and he characterized the different kinds as having five different specific energies. The idea was not new with Muller. Charles Bell had already made the same argument in [a] privately printed paper of 1811. Thomas Young had suggested in 1801 that color vision could be accounted for by three different kinds of visual fibers. John Locke's conception of secondary qualities (1690) implied that he thought that nerves are not mere passive conductors of the properties of the perceived objects, which is what Muller said he was chiefly arguing against [i.e., Muller was arguing that nerves are passive conductors]. Muller made his 'doctrine' formal in 1838, and not so many years later Helmholtz hailed it as a principle as important for psychology as is the conservation of energy for physics. (That was another principle which Helmholtz had helped to get established--in the 1840s.) Later Helmholtz extended the doctrine of specific energies to account for different qualities within each sense--three energies for colors, a thousand or more for tonal pitches, and so on. [pp. 27-28]

---

[Chapter 5 is entirely devoted to the theory of "Specific Energies of Nerves." Here's a short excerpt from near the start of the chapter.]

The doctrine of specific energies of nerves, as Johannes Muller named it, was the most important law in sense-physiology which these early decades produced. The law is associated especially with Muller's name because he had the most to say about it and insisted most emphatically upon it, and it is properly called the Mullerian theory when it is to be distinguished from the extension which Helmholtz gave it.

[boring goes on to detail that Bell had already argued for "everything of importance" in the doctrine, and others had foreshadowed it, but Muller is given primary billing because of his "explicit and precise formulation" and because of the emphasis he placed on the doctrine.]

In time the doctrine became almost a dogma, and the fact that it does not quite make sense nowadays is due in part to the way in which the theory of sensory centers supplanted it and in part to the fact that the meaning of the word energy changed radically with the formulation of the theory of the conservation of energy. Muller meant quality by energy, and we still hold the belief that different neural systems excite different sense-qualities, even though we must now think of all neural impulses as alike in nature. [pp. 80-82]

Ellen

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[Ellen Stuttle]

Dragonfly, I think we're enmeshed in a verbal snare again. No one is saying that retinal excitation isn't required for vision. The issue is what produces the excitation, whether the retinal image as such is what does it. The retinal image isn't "simply the pattern of the photons that strike [the retina]" (your post #272). The image is a visible phenomenon produced because of the eye's construction being like that of a camera. The question is whether the image qua image excites the retina. Muller thought, yes. See the passage I posted from Boring's A History of Experimental Psychology, in which Muller's view is summarized by the sentence:

"It is plain that, for Muller, the theory of vision is merely the theory of the excitation of the retina BY the optical image" (my emphasis).

What Gibson says is that it's exactly the patterned (spatio-temporal) features of the photon arrays striking the retina which are the relevant stimulus circumstance. It isn't that light produces an image which then stimulates the retina, but that light stimulates the retina, producing a visible image as a by-product (a genuine "epiphenomenon," like the red of hemoglobin, which similarly isn't functionally relevant to the blood's transporting oxygen).

Ellen

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[reason.on]

Bell (1803) treated it in detail. Treviranus (1828) was primarily concerned with it. Muller (1838) made it the primary problem, dealing with refraction by the lens and other media, the achromatic character of the system, and the defects of the system in myopia and presbyopia and their correction by lenses. In Wagner's Handworterbuch, beside Volkmann's section on sight (1846) there is a section by Listing on dioptrics (1853), which contains the principle of the reduced eye and Listing's law of the relation of the image to the curvature of the retina and to torsion of eyes in movement. The problem by this time had been extended to binocular vision and eye-movement. [The next two sentences look ahead to the next period in psychophysics.] Such was the setting upon which Helmholtz's classical analysis of physiological optics (1866) supervened. Wundt (1862) and Hering (1868) dealt with the same problem. It was at first the fundamental problem of vision.

I thought some may be interested to know that Helmholtz's work is available online:

Treatise on Physiological Optics

RCR