I quoted a whole chapter of Rambam in Part 1 without saying anything about it, except for a one-sentence summary. So now I’ll say something about it. Sorry this is so scattershot.
The Rambam’s arguments about free will focus on issues of divine decree and foreknowledge. I wonder how easily the divine challenges to free will translate into the challenges from physics and psychology. For Spinoza they should translate quite well, given that to him God and Nature are the same (to simplify what SEP reports to be a controversial point). But even without Spinoza, the challenge from deterministic physics sounds similar to the challenge from divine foreknowledge, and the challenge from psychology sounds similar to the challenge from divine decree. Similar how, exactly? And how exactly are they different? Could be insightful to pursue that.
In halakha 1, the Rambam notes that free will is a unique human attribute. Interesting that he cites the Tree of Knowledge of Good and Evil as the source for this. Others (Rabbi Saadia Gaon?) might say that man was created with this attribute. Anyway, to assert today that will is uniquely human would have to mean that will is fundamentally metaphysical, since a human brain has no qualitative differences in physiology from a non-human mammal brain.
I have a half-baked suggestion regarding the Rambam’s paradox in halakha 5, where human choice and divine knowledge are incompatible. Suppose that the act of free will is a man deciding, at the moment when he perceives his superposition collapsing, which branch of history he will follow in the many-worlds parallel universe. From God’s omniscient perspective sees each of those parallel worlds. In other words, God sees the entire tree of possible history, while the human subject decides which branches he will experience. Contradiction resolved. I don’t even have to concede the many-worlds interpretation; in the world of my consciousness, the other parallel universes don’t exist, while they still exist in God’s knowledge. I may be missing a fallacy and am probably pushing some antinomy under the rug, but for now I’ll take the glory of solving a millennia-old problem.* If any of these people are already suggesting this, I apologize for not reading about them.
[*UPDATE, 4/1/2012: Upon discussion with Reuven Rand, it seems that all I did here was reformulate the paradox in the terminology of many worlds. The root of the paradox is still there: if
God knows in advance which branches of the tree “you” will experience, then how are you able
to choose your branch?]
Another addendum to Part 1: I left out a significant aspect of Dr. Aaronson’s talk, namely Penrose’s idea that the human brain is a quantum gravity computer. I hadn’t heard of it before, and apparently it’s an attempt to explain consciousness, an issue obviously connected to free will. Aaronson had three objections. First, “A brain sure doesn’t look like a quantum computer…it’s hot and wet.” Second, the things that a quantum computer is good at, like factoring, humans aren’t so good at. Someone pointed out during the discussion that human thought processes seem totally different from computer algorithms anyway, so it’s not really a fair objection, which occurred to me too. Third, why does a quantum computer explain consciousness better than any other type of computer? I suspect that Penrose addresses that in his books. At least “quantum gravity computer” sounds really fancy, and consciousness is pretty fancy.
One last point for now: if you want an idea of how skeptically secular philosophers have viewed free will, here’s a great New York Times column. Money quote: “The more you scrutinize it, the more you realize you don’t have it.” Ah, those tipshei umot ha-olam.
