I think a brain architecture/algorithm that would debate about free will would have been adapted for large amounts of social interaction in its daily life. This interaction would use markedly different skills (eg language) from those of more mundane activities. More importantly it would require a different level of modeling to achieve any kind of good results. One brain would have to contain models for complicated human social, kin and friendly relationships, as well as models for individuals' personalities.
At the center of the mesh of social interactions would be the tightest wad connections. That would be the brain/person, interacting with and modeling all the other members of their tribe/society. However, their brain cannot model itself modeling others with perfect fidelity, and so many simplifications are made even there. These simplifications pile on top of the perceptual differences that a human sees between (itself, other humans) and (everything else). A whole different mental vocabulary arises between descriptions/models of fellow humans and descriptions/models of everything else. Only in humans does it make predictive sense to talk about intent, capability, and inclination, and the wide gap between these kinds of perceived "properties" of fellow socially interacting humans, and the generally much simpler properties seen in inanimate objects and animals, leads the brain to allocate them to widely separated groups of buckets. It is this perceived separation in mental thing-space that leads to the the a free-will boundary being drawn around the cluster of socially interacting humans. When this boundary is objected to, people go their natural arguing ways.
This is just a first attempt, so I think I may have fallen for some of the traps specifically proscribed against in the post. I hope others will attempt to put up their own explanations and maybe even poke some holes in mine :)
I'll definitely pay attention to further comments on this homework assignment.
"I see only rationality here. Whereever it is not immediately obvious, it is a quote on beauty, which is a special case of rationality." --Stefan King
Eliezer: You may be a step ahead of me, but I think this is a perfect quote to put into your file.
EY: There should be a "one" in "met or two" :)
Hopefully tomorrow's suggestion will be communicable enough so I can tell it to my fellow voters, since I'm still not quite old enough myself.
EY: I'd just like to point out that there's an extra hyphen added onto the second link to the singinst blog. Luckily enough the site doesn't totally die on it, but It would still be better if it were fixed :)
I hope I'll come up with some more insightful comments in the future than little bug fixes. Keep up the great work!
I think "cancer paper writing journal papers isn't going to experience a miraculous remission" should read patient instead of the first paper. Although, I would think if we had the kind of sophisticated AI that would allow papers to write papers we would probably be well on the way to curing cancer...
Eliezer: "you will not see the known laws of physics violated in any particular." <- shouldn't there be a "way" at the end of that?