Patrick comments on Open Problems Related to Solomonoff Induction - Less Wrong

27 Post author: Wei_Dai 06 June 2012 12:26AM

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Comment author: Patrick 17 June 2012 11:54:49AM *  1 point [-]

I take your point re: length vs speed. The theorem that I think justifies calling Kolmogorov Complexity objective is this:

"If K1 and K2 are the complexity functions relative to description languages L1 and L2, then there is a constant c (which depends only on the languages L1 and L2) such that |K1(s) - K2(s)| <= c for all strings s."

(To see why this is true, note that you can write a compiler for L2 in L1 and vice versa)

I don't see why code modelling symmetric laws should be longer than code modelling asymmetric laws (I'd expect the reverse; more symmetries means more ways to compress.) Nor why 3 spatial dimensions (or 10 if you ask string theorists) is the minimum number of spatial dimensions compatible with intelligent life.

The whole point of Solomonoff induction is that the priors of a theory are not arbitrary. They are determined by the complexity of the theory, then you use Bayes rule on all theories to do induction.

Comment deleted 17 June 2012 12:34:55PM *  [-]
Comment author: Eliezer_Yudkowsky 17 August 2012 09:52:59PM 1 point [-]

A kilobit of improbability requires only a kilobit of data to offset it, which isn't very crackpot at all. Proving minimum length is impossible, but proving an upper bound on length is very easy, and that proves a lower bound on probability.