Caledonian: Sure you do. That's why we have biology and chemistry and neuroscience instead of having only one field: physics.

That's just a matter of efficiency (as I have tried to illuminate). There is nothing about those high level descriptions that is not compatible with physics. They are often more convenient and practical, but they do not add one iota of explanatory power.

PK: I don't see the ++ in your nice example, it's perfectly valid C... =)

Caledonian, Ian C.: I know of no models of reality that have superior explanatory power than the standard reductionist one-level-to-bind-them-all position (apologies for the pun). So why add more? In a certain way "our maps [are] part of reality too", but not in any fundamental sense. To simulate a microchip doing a FFT, it's quite sufficient to simulate the physical processes in it's logic gates. You need not even know what the chip is actually supposed to do. You just need a very precise description of the chip. If you do know what it's doing, it's of course much more efficient to directly use the same algorithm it is also using. That will also dramatically cut down on the length of it's description. But that does not make the FFT algorithm fundamental in any way. It is just a way to look at what is happening. I mean, really, this shouldn't be so hard to grasp...

• Sarah is hypnotized and told to take off her shoes when a book drops on the floor. Fifteen minutes later a book drops, and Sarah quietly slips out of her loafers. “Sarah,”, asks the hypnotist, “why did you take off your shoes?” “Well . . . my feet are hot and tired.”, Sarah replies. “It has been a long day”. • George has electrodes temporarily implanted in the brain region that controls his head movements. When neurosurgeon José Delgado (1973) stimulates the electrode by remote control, George always turns his head. Unaware of the remote stimulation, he offers a reasonable explanation for it: “I’m looking for my slipper.” “I heard a noise.” “I’m restless.” “I was looking under the bed.”

The point is: That's how the brain works, always. It is only in special circumstances, like the ones described, that the fallaciousness of these "explanations from hindsight" becomes obvious.

Frank Hirsch: How do you propose to lend credibility to your central tenet "If you seem to have free will, then you have free will"?

Ian C.: I'm not deducing (potentially wrongly) from some internal observation that I have free will. The knowledge that I chose is not a conclusion, it is a memory. If you introspect on yourself making a decision, the process is not (as you would expect): consideration (of pros and cons) -> decision -> option selected. It is in fact: consideration -> 'will' yourself to decide -> knowledge of option chosen + memory of having chosen it. The knowledge that you chose is not worked out, it is just given to you directly. So their is no scope for you to err.

No scope to err? Surely you know that human memory is just about the least reliable source of information you can appeal to? Much of what you seem to remember about your decision process is constructed in hindsight to explain your choice to yourself. There is a nice anecdote about what happens if you take that hindsight away:

In an experiment, psychologist Michael Gazzaniga flashed pictures to the left half of the field of vision of split-brain patients. Being shown the picture of a nude woman, one patient smiles sheepishly. Asked why, she invents — and apparently believes — a plausible explanation: “Oh — that funny machine”. Another split-brain patient has the word “smile” flashed to his nonverbal right hemisphere. He obliges and forces a smile. Asked why, he explains, “This experiment is very funny”.

So much for evidence from introspective memory...

Frank Hirsch: "I don't think you can name any observations that strongly indicate (much less prove, which is essentially impossible anyway) that people have any kind of "free will" that contradicts causality-plus-randomness at the physical level."

Ian C.: More abstract ideas are proven by reference to more fundamental ones, which in turn are proven by direct observation. Seeing ourselves choose is a *direct observation* (albeit an introspective one). If an abstract theory (such as the whole universe being governed by billiard ball causation) contradicts a direct observation, you don't say the observation is wrong, you say the theory is.

Yikes! You are saying that because it seems to you inside your mind that you had freedom of choice, it must automagically be so? Your "observation" is that there seems to be free will. Granted! I make the same observation. But this does not in any way bear on the facts. How do you propose to lend credibility to your central tenet "If you seem to have free will, then you have free will"? To this guy it seemed he was emperor of the USA, but that didn't make it true. Also, how will you go and physically explain this free will thing? All things we know are either deterministic or random. If you plan to point at randomness and cry "Look! Free will!", we had better stop here. Or were you thinking about the pineal gland?

Nominull: I believe Eliezer would rather be called Eliezer...

Ian C.: We observe a lack of predictability at the quantum level. Do quarks have a free will? (Yup a shameless rip-off of Dougs argument, tee-hee! =) Btw. I don't think you can name any observations that strongly indicate (much less prove, which is essentially impossible anyway) that people have any kind of "free will" that contradicts causality-plus-randomness at the physical level.

I wish I knew where Reality got its computing power. Hehe, good question that one. Incidentally, I'd like to link this rather old thing just in case anyone cares to read more about reality-as-computation.

I know a really bad one which nearly turned my stomach: Some newspaper wrote "Survey uncovers that X's have the property Y!" (I forget the details). I read the article and it turned out that, according to some survey, most people believe that X's have the property Y. Argh!

Frank, what does that have to do with the quality of the paper I linked?

James, everything. The paper looks very much like the book in a nutshell plus an actual experiment. What does the paper have to do with "And I know you didn't simply leave out an explanation that exists somewhere, because such understanding would probably mean a solution for the captcha problem."? I find these 13 and 12 year old papers more exciting. And here is some practical image recognition (although no general captcha) stuff.

James Blair: I've read JH's "On Intelligence" and find him overrated. He happens to be well known, but I have yet to see his results beating other people's results. Pretty theories are fine with me, but ultimately results must count.