Monday, May 14, 2007

Randall C. O'Reilly's Wiki

This is one of the best things I've read in a while. It's a very detailed, personal account of Randall O'Reilly's belief system, covering the brain, epistemology, religion, physics, politics, and much more. I just finished reading the whole thing, which was very refreshing.

I especially enjoyed the constant focus on developing self-consistent beliefs as a practical goal: "Self-consistency is probably the only useful criterion for establishing the "truth" of a belief system. It is itself consistent with the fact that we cannot escape our fundamental subjectivity..." Here's another great quote: "You might argue that this is all circular. It is. However, if you make a big enough circle that encompasses all of experience, then I don't see what the problem is."

I think self-consistency is implemented in the brain as a Bayesian network. New pieces of evidences are constantly coming in through sensors and being passed around among nodes to update their beliefs about the world. The whole belief propagation mechanism is designed to maintain self-consistent beliefs as well as possible; complete self-consistency isn't always achieved, but it's at least maximized. Interestingly, we are still able to bias the system by focusing attention on certain details while ignoring others, which can basically keep certain pieces of knowledge from affecting our belief systems.

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