Monday, June 27, 2005

Hasker on Stapp

In the course of the previous discussion of the unity of consciousness and physicalism, I got som responses from Mike Wiest, who took a position that anti-physicalist arguments work against physicalism if the "physical" is understood in terms of classical physics, but quantum mechanics opens the door to answer the questions posed by these arguments. My initial reaction was that this was a form of scientific idealism and a rejection of mechanism at the level of fundamental physics. I sent the link to Stapp's paper, which Wiest recommended, to William Hasker, who responded as follows:

Greetings! Your query about Wiest’s message came at a (relatively) good time – no major projects are underway at the moment, and I am pretty well caught up on F & P stuff. So, I printed out Stapp’s article, and have been trying to figure it out.

To begin with, I think Stapp does have a fairly good grip on the unity-of-consciousness argument, and on the evolutionary version of the Argument from Reason. Roughly, the idea seems to be this: a “thought” – say a belief – typically involves nervous activity in widely scattered parts of the brain. But, on classical assumptions, each micro-area within the brain is in direct causal contact only with immediately adjacent areas; also, the physical description of what is going on at a given point in the brain (i.e., values for the several physical “fields” at that point) is far too simple to register a complex state of consciousness. So consciousness, if it exists, must be something “external” to the brain, but then (assuming causal closure) it would have no effect on behavior and would confer no evolutionary advantage, and would thus be scientifically inexplicable. This is pretty rough, and it’s a mixture of what he says and some of my own ways of putting things, but I do think it basically captures what he is saying up through section 2.

The tricky part begins in section 3. I’ve tried to figure out the mathematical notation; it doesn’t help that parentheses have got converted into tildes, and some guesswork is involved in putting them back! I think I’ve got a fair grip on what he is saying up through 3.5. But what he says about the quantum-mechanical description of a system leaves me in the dust. I can to some extent interpret the formulas, but I have no idea what they represent or what the point is of describing the system in the way he sets out. So for present purposes, I have to take it on faith that he knows what he is talking about. But the payoff (in 3.9f) seems to be this: the quantum-mechanical description of a system (such as the brain) is enormously more complex than the classical description, such that (I hope I’ve got this straight!) a description of what is going on at any one point involves the simultaneous de­scrip­tion of what is happening at all the other points in the system. Thus, the quantum-mechanical state-description, unlike the classical state-description, is sufficiently complex to correspond to a belief or some other complex state of consciousness.

This amounts, in fact, to a kind of ontological holism: “The fundamentally holistic character of the quantum mechanical description [of] nature is perhaps its most basic and pervasive feature” (3.12). And this does respond to the challenge of the UOC argument: to account for the UOC, we need something that functions holistically rather than atomistically, as physical reality does on a classical model. Actually, 3:11 is the bit that best summarizes the point of this section as a whole.

So far, this does not tell us why thought is involved in the quantum-mechanical process. (Note that all of the above would apply to any physical system, not just to the brain.) I take it the following section is supposed to help with this. Or rather, to point us in the direction of other work of the author’s (surprise, surprise!) that does the job. The big promissory note (so far as the present article is concerned) is the claim that the author’s theory “appears to be able to explain in terms of the laws of physics the causal connections underlying human behavior that are usually explained in psychological terms” (4.7). My reaction, as you may surmise, is along the lines of: “This blank check and a dollar bill will get you a can of pop out of the machine.” Of course, the author apparently has made an effort, in his book, to cash out the promissory note. My instinct, however, is that the Argument from Reason is going to kick in here, and I see nothing that suggests he will have a good answer to it.

The “Conclusions” (section 6) summarizes very nicely the limitations of classical physics (as captured by the UOC argument) in providing an understanding of mentality. The way in which quantum physics overcomes these limitations is, unfortunately, not spelled out with equal clarity.

Appendix A gives some of the basics of the author’s theory, which strikes me as extremely interesting though highly speculative. (Incidentally, I believe David Chalmers has recently come out for something roughly along these same lines.) It’s possible that the holistic character of quantum mechanics can be used to account for the holistic nature of thought. But I see nothing so far that shows me that Stapp has crossed the divide (or perhaps, even seen clearly the divide) between the “mechanistic” nature of matter and the intentional and teleological character of thought, as featured in the AFR.

I guess I’ll leave it at that, for now. Does this help at all towards clarifying your perplexity about the material? And, do you have any further thoughts to share? This really is interesting stuff, though the author has lots to learn about writing for non-physicists.

6 comments:

Mike Wiest said...

Howdy; Wiest here. I hope a few comments from me will clarify rather than muddy the waters...

First, about the scope of that Stapp article. (Sorry I couldn't find a version without the damn tildes.) I brought it up only with respect to the unity of consciousness. Neither I nor that Stapp article were trying to make a general case against "non-physicalism." The point is limited to this: classical mechanics does not allow irreducible wholes, but quantum mechanics does.

So while I'd quibble a little bit with your summary of Stapp's arguments, the main point is, as you say, the "ontological holism" of quantum theory. It's not about needing enormous complexity, it's about the need to objectively "bind" a multiplicity into a unity to account for the unity of each moment of consciousness. (Maybe this is only a "need" for a physicalist account.)

So, so far the argument is not claiming to explain consciousness, but merely saying this physical theory LEAVES ROOM for an irreducibly unified (and causally efficacious) consciousness, whereas a classical model RULES IT OUT. The quantum picture as sketched so far does not explain why particular states would be conscious, for example (neither do the rest of Stapp's writings). It just gives us a self-consistent way of imagining the possibility of unified conscious physical states.

Second: So the point here was limited to unity. But you guys are naturally interested in pressing on further to conclusions about non-naturalism or non-physicalism. So I'll try to indicate how the quantum picture might be able to deal with other problems, like "reason." I should admit two things first: (1) I'm not familiar with the argument from reason and related arguments; and (2) I don't really understand what non-physicalism means: i.e. if there is a new thing or influence not covered by present -day physics, why can't I consider it "new physics" instead of "supernatural"? Is it because you can't get morality from physical variables?

Anyhow, given those two major handicaps, I'll just point out that quantum mechanics leaves open the possibility of some kind of genuine free will or reason, in the form of non-mechanical, non-deterministic, but NON-RANDOM behavior. Many physicists would dispute the non-random part, but I believe I can support what I'm asserting if you want to go into it. With respect to "teleological" behavior: when one combines Einstein's relativity with quantum mechanics, you get "virtual" causal influences travelling forward AND BACKWARDS in time--this may be the opening for "forward-looking" behavior by physical systems. Of course these are just vague possibilities as I'm suggesting them here: the only "promisary note" I'm really offering is one that says you're right to think that classical mechanics can't do the job.

For my last comment I want to make clear that I'm speculating way beyond Stapp. In many quantum brain -type models, conscious moments are associated with the "collapse of the wave function," in which one of many possibilities is "actualized." However, this wave-function collapse is itself poorly understood, so there are a number of theories about it. In some, quantum gravity interactions couple the brain to "global modes" that are delocalized in space and time, and which can involve the whole universe. (There's an engaging popular account of such a scheme at http://www.coldcure.com/html/
quantumphysics.pdf.) Now the authors of these ideas are atheists, I'm pretty sure. However, these ideas seem to me to offer a glimmer of a way to understand some of the assertions of saints and mystics. In particular, I'm referring to stuff like that we can see directly into the fundamental reality, that we have a divine spark, that we have a connection to eternity, that the divine in us is the actor and the witness (as in the Hindu Bhadgavad Gita), etc. The crazy quantum gravity models start to show how those claims could be literally, physically true (if I think of God or Heaven or the Divine as "the one without a second" ie the whole cosmos throughout all time and eternity).

At this stage of my development I tend to think that there is just one truth, not a physical truth and a spiritual truth. So rather than choosing "anti-physicalism" or "physicalism," I'm just looking for a way to have a self-consistent world view that includes everything--including consciousness. Classical mechanics can't do it, but quantum mechanics (plus any new physics...) might.

By the way, it's really cool that you guys are trying to figure out this unfamiliar stuff that might appear hostile to your beliefs...

Hope this helps...

Clark Goble said...

With regards to QM and consciousness. A few things I've never seen people answer satisfactorily.

1. Exactly why should we assume there is a unified quantum phenomena across the brain. Given the nature of cells in the brain and the limited electro-chemical communication, it seems that at best quantum effects would be only very narrow in range. i.e. it seems that we'd only be slightly more expansive than what classical physics would describe and then just because of electrical effects.

2. Any appear to "collapse of the wave function" seems to me to be tying oneself to a very particular and problematic interpretation of quantum mechanics. Why assume the "collapse of the wave function" is anything more than a mathematical artifact? I don't see why we have to assume Von Neumann's approach is the best way. Indeed I can think of numerous problems with it, not the least of which is this mysterious collapse. While I don't really buy Bohmian mechanics, it certainly offers an alternative.

I tend to see emergent theories of consciousness as problematic. Admittedly the quantum chaos interpretation offers a lot. But ultimately I don't see it being that different fundamentally than what one could achieve classically. i.e. I don't see how it avoids the physicalist reduction.

Mike Wiest said...

Briefly:

1) Your question involves two parts: (a) how could it be possible to have a macroscopic quantum state across the brain, when we are told quantum mechanics only applies to very small or very cold things? and (b) even if it's possible, why would we think it might be true?

(a) Quantum effects are not just microscopic. Superconductors are an example of something irreducibly quantum and macroscopic. The Aspect non-locality experiments have demonstrated non-local causal influences out to ~50 km, and there's no reason to think it stops there. Re: brain temperature: Tegmark has claimed to show that the temperature rules out macro quantum effects in the brain. But his argument is based on assuming a system at thermodynamic equilibrium, which the brain is not, because it has a constant flow of energy through it (via ATP). The Frohlich model (circa 1968) gives a rigorous model of how energy flow through a system of electric dipoles (modelling bio-molecules, which are often polar) can cause the system to "condense" in to a coherent quantum state--at high temperatures. Tegmark didn't mention that model.
(b) The unity of consciousness is the reason to think there really is a macro quantum state in the brain. Because if the brain is purely classical, nothing that could correspond to a unified percept is allowed in the physical theory. If you tack such things onto a classical theory, they must be epiphenomenal. But if qualia are epiphenomenal, they could not evolve by natural selection, so there would be no explanation for why fire hurts and sex feels good--because the feelings could have no effect on the behavior. Roughly, introspection leads us to believe there are irreducible wholes; there are such things in quantum theory but not in classical theory.

(2) According to my understanding, there is no way to treat the wave-function as merely epistemic, ie just about our knowldege. The Bohm picture avoids the ideterminacy of the Copenhagen interpretation, but no interpretation avoids the non-locality or holism associated with measurements. That goes for the "Many-Worlds" interpretation too.

I'm not invoking chaos at all. I think that's a big red herring in the context of trying to understand consciusness. The main thing that I'm claiming quantum offers that classical cannot is ontological holism. I also think there is room for some kind of genuine free will in quantum mechanics but not in classical mechanics.

I don't understand what you mean by "avoiding the physicalist reduction." Could you clarify that?

Ahab said...

Mike Wiest wrote:
"I also think there is room for some kind of genuine free will in quantum mechanics but not in classical mechanics."

----------------------------
Not sure it is a good idea to try and accomodate the theory and practice of brain science to a metaphysical notion like 'free will'. Obviously the brain is capable of making decisions. Why not try and learn how it is able to make those decisions? Especially in view of the fact that there is, to my knowledge, not even a coherent explanation for how free will could work in a non-deterministic environment.

Mike Wiest said...

Hi Ahab,

No, I don't know of any kind of naturalistic theory of free will (assuming we disregard "compatibilists" who are just determinists redefining freedom so it will be deterministic). And I sure don't want to be advocating any kind of "accomodation" on the part of science, if that implies some kind of bowing to irrational political pressure or something. And I certainly agree that we look in the brain for how decisions are made.

However, if, on independent grounds, we come to the conclusion that a deterministic account of mind can't be the whole story, then we legitimately look in the brain to find the indeterminacy. I think there are a number of ways to come to the conclusion that the mind cannot be NOTHING BUT a computer program. Searle's Chinese room is one, and Penrose/Lucas's Godelian argument is another. If you are a neuroscientist who feels strongly that neural net models can (read--"will soon be able to") account for all our behavior, you may not feel the full force of those arguments, and may find reasons to disbelieve them. From a conservative neurobiological perspective like that, one operates on the assumption that classical neurons can do the whole job until there's an neurobiology experiment they can't account for--and we can safely ignore the philosophers and their thought experiments until then. That's not quite how I feel, but I guess we'll figure it out eventually one way or the other.

In any case, I take your point that the term "free will" has lots of baggage and I didn't bother to define it and probably couldn't. Throwing emotionally charged metaphysical terms around might be counter-productive. But the point I stick to is: quantum mechanics has wiggle room for us to entertain notions of non-random non-determinacy; classical mechanics does not.

I might add, for the non-physicalists, that postulating a nonphysical soul to make rational decisions doesn't let you avoid the issues I'm worrying about with Ahab (who appears to be a physicalist of some sort...). If "reasons" cause you to do something your mechanical body does not allow, that's a contradiction. Dualism is not contradictory, but a theory that predicts a body does two different things is contradictory. So the problem for everybody (since Kant, I guess) is how to find a causal account for mental properties that is COMPATIBLE with physical theory, without forcing the mental to be epiphenomenal.

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