Lots of stuff going on in this thread that I'm interested in ... so I'll see what I can add.
spar: I don't think I even saved the links of the online QM lectures I found. I just d/l'ed a bunch of stuff on my hard-drive on my other computer. I can do you one better, though, and put it all in a .zip file and upload it on myfile.com or something, then I'll post the link for that. But I have to get internet access for that computer first.
As for my thinking on the topic of free will and mind ... I generally like Dennett, too. I actually took a seminar course specifically on his book Consciousness Explained (and a few other books) ... I have a bunch of nitpicks with him, too, but mostly in the details and not the larger picture, which I see as the right attitude towards naturalism. (Well captured by an old Larson (I think) cartoon which had 2 scientists looking at a frighteningly complicated math equation, except step #3 was "And then a miracle occurs" and then the equation continues. And one scientist says to the other: It's great! But I'm a little worried about your step 3 here. If any explanation has that step in it in one way or another, it's a nonexplanation.)
As for Penrose's argument, for the mind part he was heavily relying on some shoddy arguments: one a vulgarization of Searle's Chinese Room argument that the firing of neurons can't be "about" something like thoughts are "about" something; another an old hat argument that Godel's Incompleteness Theorem requires the brain to be more "open" or non-computational or something. Aside from the fact Penrose botched these arguments in their own right, both of them have aged very poorly, and even in their best days they couldn't get you far because they only support the negative thesis that Hebbian dynamics alone aren't enough for conscious thought, without lending any real guidance for what would be enough. But it's my perception that both of them, or for that matter the entire trend of anti-naturalist and anti-AI arguments you see in some circles nowadays: (1) severely underestimate what Hebbian dynamics is capable of and (2) severely exaggerate the limitations consciousness, "free will", language, logical intuition, etc., are supposed to put on the brain.
As for what *can* do the work in cases that we normally call "free will", probably the best approach is to point to some suggestive work in neurophysiology that's making the most progress, rather than trying to over-speculate.
So some of the most interesting was published in a great book by Glumcher called "Neuroeconomics" ... Bear with me a little while if you want the punchline: A lot of work on the neurophysiology of decisionmaking is concentrating on a brain area called LIP. It is the bridge-area exactly between afferent signals coming in from the retna (images) and efferent signals going out to the eye-muscles (behavior), and its function was for a long time questioned, since it didn't seem either afferent or efferent, although its wiring and behavior was very well understood. Glumcher and others have put together a fantastic case that, in fact, LIP maps "relative expected utility" for looking at something ... and when you look at its firing patterns that's exactly what you're seeing. Areas that offer a benefit to the organism get activated; areas that don't get deactivated ... and that feeds into what the eye "wants" to look at. And when the benefit to the organism changes, so does the activation. And when there are two or more areas to look at that offer the same expected risks/benefits, you see both light up, and the eye muscles hesitate between the two and over a number of cases it seems as if the eye is choosing "randomly" between the two (50%). But it's actually not "random" at all, because it's what you'd expect for an organism optimizing its utility to a Nash equilibrium (NE= any deviation from the x% pattern of choices would reduce utility). Small deviances in utility suddenly take a larger role (the little feeling you get that the right queue is a hair faster than the left queue), and there's apparently a memory that tracks choices over time so that it hits almost exactly the optimization for the Nash equilibrium over many attempts, be it 30/70%-A/B, or 50/50, etc...
So the point here is you get what looks like "random", "free", "nonalgorythmic" behavior that's actually controlled by very normal Hebbian dynamics. No need for weirdo quantum effects to get "random looking" behavior, the little oomph to choose between A or B. First of all, it's important not to see the behavior as actually *random*. The variation is actually very tightly controlled; life is like a game, and people play games to win, even being sneaky and "random looking". And because utility is at stake, the *last* thing the system wants to do when it's playing the percentages is throw *another* wildcard into the mix.
So that's one thing.
Another set of studies has to do with the actually "feeling" of volition we get while acting, when it occurs, and what causes it. I'll post this later on if there's interest ... but there is a mechanism which controls this, and what's interesting about it is that sometimes it doesn't line up with actual behavior, so sometimes we feel volition for actions we don't take (ghost limb experiments, or the "mirrored hand" effect), or even more weird but even more common: we feel the volition of choosing an action *after* the brain has already choosen it and sent the signal to the muscles. But the mechanism/feeling is not as illusionary as this suggests; there's still a core part about it that has something to do with "me" making a choice and the feeling is of that decisionmaking, not something that comes after it. Ok, that's another can of worms I'll need to take on later, and raises all sorts of phil issues of freedom and will. For now, I just wanted to explain what I didn't like about Penrose.
Edited by demagogue, 10 April 2006 - 02:04 AM.