The Open Thread posted at the beginning of the month has gotten really, really big, so I've gone ahead and made another one. Post your new discussions here!
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
"AIXI is a universal theory of sequential decision making akin to Solomonoff's celebrated universal theory of induction. Solomonoff derived an optimal way of predicting future data, given previous observations, provided the data is sampled from a computable probability distribution. AIXI extends this approach to an optimal decision making agent embedded in an unknown environment."
Okay, you're right, my apologies. The point about uncomputability and uselessness of the decision theory still stands.