Imagination and Causality in Quantum Physics

[Dragonfly]

The retinal image isn't "simply the pattern of the photons that strike [the retina]" (your post #272).

Yes it is, this 2-dimensional pattern produced by the refraction of light rays coming from a 3-dimensional world is by definition an image; just check any book about geometrical optics.

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).

This is a typical example of verbalism, creating imaginary problems by a meaningless playing with words. These are just different descriptions of one and the same phenomenon, the image is not a "by-product", it is the pattern of light that stimulates the retina. This reminds me of someone who told me once that it was "wrong" to say that plants grow towards the light, no, you should say that the cells in the dark parts of the plant grow faster than in the lighted parts and that as a result the top of the plant was bent into the direction of the incoming light. Nonsense of course to say that this is "correct" and saying that the plant is growing towards the light is "wrong", both statements are equally correct, the second one only gives somewhat more detail than the first one, but that doesn't make the first one incorrect. I've seen a lot of such verbalist arguments on Objectivist forums (they are probably popular in philosophy in general), and I find that kind of discussions a complete waste of time.

[Ellen Stuttle]

Dragonfly, if you think that what I'm trying to explain to you is mere verbalism, I can only conclude that you didn't read the material I posted about how psychophysicists of about the first half of the 19th century approached the problems of visual perception. I'll repost part of the material I copied in post #273 from Boring's A History of Experimental Psychology. And please do keep in mind reading this that we're talking in the context of 19th-century theories of the nature of light. They didn't even have the 20th-century theory of photons at that time. They thought of light as waves propagating in a luminiferous aether. The mechanism being proposed here isn't what you're thinking of the mechanism as being. The difference is much more than verbal. (If you don't "see" the difference from reading this, I don't know what else to say and shall give up, at least for now.)

The facts [of the eye as an optical system] were [considered] 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 [emphasis added], 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.

[....]

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).

---

I'll add about the example you gave that I don't consider that an example of "verbalism" either, depending on the context in which one is talking. You wrote:

[DF, post #276] This reminds me of someone who told me once that it was "wrong" to say that plants grow towards the light, no, you should say that the cells in the dark parts of the plant grow faster than in the lighted parts and that as a result the top of the plant was bent into the direction of the incoming light. Nonsense of course to say that this is "correct" and saying that the plant is growing towards the light is "wrong", both statements are equally correct, the second one only gives somewhat more detail than the first one, but that doesn't make the first one incorrect.

In casual parlance, to speak of a plant growing toward the light is good enough to do the job. But if one is talking in a scientific context, no, it isn't strictly correct, since there it's a way of speaking which is a holdover from vitalist sorts of theories in which the plant is being credited with a form of desire to reach the light.

Ellen

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Edited October 12, 2006 by Ellen Stuttle

[Dragonfly]

Dragonfly, if you think that what I'm trying to explain to you is mere verbalism, I can only conclude that you didn't read the material I posted about how psychophysicists of about the first half of the 19th century approached the problems of visual perception. I'll repost part of the material I copied in post #273 from Boring's A History of Experimental Psychology. And please do keep in mind reading this that we're talking in the context of 19th-century theories of the nature of light. They didn't even have the 20th-century theory of photons at that time. They thought of light as waves propagating in a luminiferous aether. The mechanism being proposed here isn't what you're thinking of the mechanism as being. The difference is much more than verbal. (If you don't "see" the difference from reading this, I don't know what else to say and shall give up, at least for now.)

What's the use of this? I don't give a damn about 19th century theories, no doubt they'll not be as accurate as modern theories, but so what? I didn't come up with them, so why dredge them up? I can only conclude it is a straw man technique by suggesting that what I say is the same as some antiquated theory, merely while we both use the word "image".

In casual parlance, to speak of a plant growing toward the light is good enough to do the job. But if one is talking in a scientific context, no, it isn't strictly correct, since there it's a way of speaking which is a holdover from vitalist sorts of theories in which the plant is being credited with a form of desire to reach the light.

Oh my god... this kind of PC (Philosophically Correct) talk drives me crazy. What do we care about some morons who believe in vitalist theories? By the same reasoning we no longer could say that the Earth moves around the sun (while some idiot might think that the Earth desires to move around the Sun), and we couldn't say that a magnetic north pole and a magnetic south pole attract each other (while some nitwit might think that this means that magnetic poles have sexual feelings). Arrrrrgghhh! Stop this nonsense!

[Ellen Stuttle]

What's the use of this [my posting a passage describing theories of vision in the first half of the 19th century]? I don't give a damn about 19th century theories, no doubt they'll not be as accurate as modern theories, but so what? I didn't come up with them, so why dredge them up? I can only conclude it is a straw man technique by suggesting that what I say is the same as some antiquated theory, merely while we both use the word "image".

Dragonfly, I can't imagine why you see no use in understanding the background of and context in which the questions pertaining to a scientific subject you're trying to talk about are posed. Communication is very difficult if terminology is used in different ways, for one thing. For another, specifically pertaining to theories of visual perception, the early theories are still very much with us in setting paramaters of debate, in setting a framework from which people approach the questions. (A major thing Gibson was doing was trying to change the framing of the questions so as to correspond to the realities of how the visual field is processed instead of retaining the hangover of point-by-point modeling of vision.)

It does seem, though, to be the moral of your and my current exchange that little profit is to be had from our attempting dialogue on...well, basically anything to do with perception, cognition, how the brain actually works. This business of different uses of "image" when referring to visual perception is a small issue compared to some of the larger discrepancies of usage between us. I think we wouldn't get very far attempting to discuss the discrepancies.

But there are some others reading this exchange. (I noticed, e.g., that Martin Radwin was reading it when I opened your reply.)

Thus, in the hopes of making my point clear to anyone else reading who might be puzzled about it, I'll synopsize what I've been attempting to explain about the difference between what's called "the retinal image" and the pattern of firings of the photo-sensitive neurons of the retina. The "image" I've been speaking of is the photographic image which forms on the surface of the retina, an image which can be seen if one is looking at a retina (in proper conditions). This image is a separate phenomenon from the pattern of neuronal firing. Dragonfly is referring to the second, the pattern of neuronal firing, in speaking of what he calls a "2-dimensional image" (though the neuronal layer isn't actually 2-dimensional, but I at least understand why it might be described thusly). However, the "image" which the early psychophysicists were speaking of -- and which still is meant in writings about the eye, at least as typical usage in psychophysical literature I've encountered -- is the photographic image. The early psychophysicists thought that this image was what caused -- in point-by-point fashion -- the nerve impulses from the retina (by mechanisms they didn't know; little was known about how nerves fire at that time, though it had been known since Galvani's work with dissected frogs' legs in the last decade of the 18th century that an electrical impulse would stimulate nerves in the dissected legs). Those early psychophysicists were wrong; it is not the photographic image which stimulates firings of the retinal neurons; it's absorbed photons.

Ellen

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[hbar24]

The subconscious creates fairies as symbols and they should be seen as such. That is not going astray but not puting constraints on thought. An objective view can't start with conclusions, if you see what I mean. Everything must be up for grabs at every query or we start with assumptions. It is just like adding all information to the concept or truth, even lies as they are imagined and therefore are true enough. Lies form a pattern as does truth so lies can help identify liers. Truth should include everything now and room for that to come. Even random words and pictures can be used to identify random words and pictures. That thought can best be understood intuitively. Ayn presumably had 30% more intuitive ability, if she was just the statistical 'average woman', which I somewhat doubt.

[heusdens]

I went back to RoR to read some of Bob and Dragonfly’s (Cal’s) exchanges with various others on QM. I read most of the first three pages to get a sense of the ideas that were being exchanged and of the general tone of the interactions. The ideas were interesting. The quality of the communication was more interesting. There was an apparent breakdown in communication that seemed to be frustrating to everyone and tended to cause flashes of aggressiveness and disrespect on both sides of the issue. In terms of the breakdown in communication, it made me think of the Einstein-Bohr debates.

I have long thought that the Einstein-Bohr communication breakdown was the result of two people trying to compare notes about what they believed to be the nature of existence when they produced their views via different epistemological principles. They used different methodologies to creating knowledge so neither would accept the other’s arguments for his conclusions. They talked a different language to one another.

Both Bohr and Einstein valued the evidence as the standard of reality. Both were committed to the highest exercise of reason. (So far they make good scientists or good objectivists.) Where they differed was in the value they each placed on models they were able to create in their imaginations. Einstein placed great stock in the intuitive/experiential models of reality he was able to produce by using causality to guide his imagination. It appears he viewed his imagination to be a legitimate tool for penetrating the underlying nature of existence through the modelling of existence provided his imagination was limited by certain principles.

Bohr, on the other hand, seemed to want to keep his imagination in check by not letting it stray far from the evidence or from the path mathematics takes from the evidence. On his view, we cannot say any more about reality than the evidence and mathematics will allow.

Implicit in Bohr’s approach to epistemology is a distrust in the imaginations ability to be a reliable tool for modelling reality. Because the imagination can lead us astray in our understanding of reality, Bohr tied his epistemology tightly to two rocks he trusted: the evidence and mathematics. Einstein tied his epistemology tightly to three rocks: the evidence, mathematics and causality.

The Copenhagen interpretation of QM and those who tend to align themselves with it, agree with Bohr’s approach to epistemology. The detractors of the Copenhagen interpretation, who are looking for a causal interpretation, agree with Einstein’s approach. The difference between the two sides is a matter of epistemology, not physics.

We know the imagination can lead us astray. It produces unicorns, gold mountains, magic, fairies, gods and ghosts. The question is: can the imagination be guided and honed to be a reliable tool for penetrating the underlying nature of existence as Einstein seems to assume? What would we use to guide our imaginations in this way? Is this why Objectivists are so attracted to the concepts of identity and causality? Is it because the concepts of identity and causality act as a guide, placing limits on what models can be formed in the imagination to represent reality? If so, how important is it to reevaluate and define more precisely our understanding of the nature of identity and causality?

As guiding epistemological principles, the Objectivist view of identity and causality is insufficient for providing an understanding of the possible underlying nature of quantum reality. However, there is no question in my mind that the power of Ayn Rand’s and Nathaniel Branden’s insight into existence comes from their ability to guide their imaginations–- and with this, their intuitive/experiential views of existence-- using notions of identity and causality more complex than they specified explicitly. Objectivism is Rand’s intuitive view of existence brought within her own conscious power to evolve and made explicit through her writing. Her fiction was how she brought her intuitive view of existence within her own conscious power to evolve. Her principles of identity and causality are what guided the evolution.

As epistemological principles identity and causality are a posteriori concepts not a priori axioms. The principles of identity and causality have to be abstracted from the particulars in our experience of reality. We have to look at the evidence to figure out what are things and why they behave as they do. Our statements about identity and causality have to be precisely defined to not allow into our models elements not supported by the evidence and must be inclusive enough to not leave out any aspect of reality. “What a thing is determines what it does,” does not go far enough.

Of course, there are those who will still say the imagination that strays from the evidence and mathematics has no place in epistemology. I side with Einstein and Rand on this one.

Paul

Interesting subject. What are the implications of outcomes of for instance Quantum Mechanics and General Relativity for epistemology. I think they can be substantial.

One of the important outcomes of Quantum Mechanics (EPR paradox; Bell Inequality) is that it does not match with the idea that those subatomic events have an identity. Assuming they do is the proposition that there are local hidden variables. But this was sought for extensively and many hypothesis have been formulated and checked experimently. The end result is, and this is a proven fact, that no such hidden variable theory can account for the experimental results.

Likewise in the light of General Relativity. Bodies in free fall behave according to the metric of space time.

And NOT according to their intrinsic properties or identity. Assuming identity as the cause for such motion is then quite impossible. Or one would have to assume that spacetime itself has this identity. But spacetime itself is not a finite entity, when regarded as a whole.

And another point of view. Evolution. Mankind has traditionally attributed identities to species. The traditional theistic view is that - while most will agree on what is termed 'micro' evolution, which is nothing else but evolution but taking place on smaller time scale - species or kinds are immutable. These are deeply rooted beliefs which for a great part explain the resistence from traditional religious thinkers against (macro) evolution and abiogenesis. It conflicts with the deeply rooted idea that the world exists in the form of distinguisable entities with a fixed identity.

In the light of the whole of science, this idea can not be true. The inititial configuration of the Universe shortly after the Big Bang consisted of nothing but (mainly) Hydrogen, Helium and Lithium (and perhaps a few other light elements), of which all material entities (in baryonic form) now in existence are made.

The clouds of these light elements, and seeded by the small inhomogenities formed the galaxies and stars which produced the other elements through nucleosynthesis, and these materials ejected by super-novae formed the chemical components through chemical reactions on (proto)planets, astroids, etc., eventually leading to life forms on earth.

In the light of this macro scale material transformation taking place everywhere and anytime, a concept of a 'fixed' identity for material entities is simply inadequate, or at least one-sided.

I see this (the absence of such a thing as 'fixed' or immutable identities) as a fact of science, and either we side with science, or we are left over to superstitition and/or unfounded and irrational beliefs.

I don't see a real problem with it, even when taking to the more human scale of individuality and personality. We know we are changing entities too. We have in fact become someone else in the course of our life, one never stays the same person. At any given time we DO have an identity, but yet such is not immutable to changes. In fact everything changes, society, nature, ourselves.

That is how life/nature is folks!

[Paul Mawdsley]

Hi Rob,

Welcome to OL. I've been very short on time recently, and will be for the foreseeable future, but I will try to take the time to read over and respond to your posts.

Paul

Edited March 5, 2007 by Paul Mawdsley

[heusdens]

Hi Rob,

Welcome to OL. I've been very short on time recently, and will be for the foreseeable future, but I will try to take the time to read over and respond to your posts.

Paul

Hi Paul, and hello to you too

I am rather new to this forum, and Objectivism as well (must still read some books about it, although I have read a lot of available material about it online --it's basic premisis and political ideas/worldview, and more philosophically how it differs from either Idealism and Materialism and what it's position is towards Dialectics).

You (or someone else) might want to educate me on some of the basic premises of Objectivism (as I still have some questions on the basic premises, which I posted as a seperate post).

I hope some time later we can have some good discussion about such issues, and in the mean time, I will try to understand some more about Objectivism.

Rob

[BaalChatzaf]

Dragonfly,

Causality is an Objectivist axiom. However, as an axiom, it means something different than what you guys are saying. All it means axiom-wise is that an entity will behave according to its attributes.

And some of the attributes are a function of how the entity is observed, i.e. interacted with a physical observation system. Google <Stern-Gerlach Experiment>. Also read the first few chapters of -Quantum Mechanics and Experience- by David. Z. Albert. The book is not too mathematically demanding.

Ba'al Chatzaf

[Michael Stuart Kelly]

Bob,

From what I have read so far, that is a supposition to explain certain measured phenomena, but there are other suppositions I have read (like wave and particle being identical). Before I discuss much more about quantum physics, I need to read more.

Also, just because a property operates in a certain manner at a micro level, that does not mean it operates at an entity level.

Michael

[BaalChatzaf]

Bob,

From what I have read so far, that is a supposition to explain certain measured phenomena, but there are other suppositions I have read (like wave and particle being identical). Before I discuss much more about quantum physics, I need to read more.

Also, just because a property operates in a certain manner at a micro level, that does not mean it operates at an entity level.

Michael

Actually it does. Electrons are both waves and particles. So are Buckeyball molecules (C60) which is very, very large compared to a electron. Quantum physics holds at all scales. As the mass of a system or object increases the uncertainty in position/velocity decreases which is why it looks like a baseball has a definite trajectory. It is very difficult to detect the quantum effects of a large object or system with the unaided senses which is why it took so long to discover quantum physics. There is no "cut off" for Heisenberg Indeterminism. The Standard Model applies at all scales, from the very small to the very large.

By all means, read more.

Ba'al Chatzaf