= 27d567bc2d48d9f40e9ccc20ea370b15)
shminux comments on The Problem with AIXI - Less Wrong
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (78)
Are there toy models of, say, a very simple universe and an AIXItl-type reasoner in it? How complex does the universe have to be to support AIXI? Game-of-life-complex? Chess-complex? D&D complex? How would one tell?
If you give up on the AIXI agent exploring the entire set of possible hypotheses and instead have it explore a small fixed list, the toy models can be very small. Here is a unit test for something more involved than AIXI that's feasible because of the small hypothesis list.
Game-of-life and (I assume) D&D are turing complete, so I would assume at first blush that they are as complicated as our laws of physics. They may simulate turing machines with an exponential slow-down though -- is that what you're getting it?
What I mean is that in the GoL or another Turing-complete cellular automaton one can specify a universe by a few simple rules and initial conditions. I wonder if it is possible to construct a simple universe with a rudimentary AIXItl machine in it. As a first step, I would like to know how to define an AIXItl subset of a cellular automaton.
Writing any non-trivial program in such simple cellular automata is often too difficult to be pratically feasible. Think of designing a race car by specifying the position of each individual atom.
If you've got a modular way of implementing logical operations in a cellular automaton, which we do in Life, you could automate the tedious parts by using a VHDL-like system. The resulting grid would be impractically huge, but there's probably no good way around that.
Sure
Any universe that contains AIXI would be too complex to be modeled by AIXI. AIXI requires finding programs that reproduce it's inputs exactly. But you could get past this constraint by looking for programs that predict the data, rather than recreating it exactly.
You could make it's environment an actual computer. Something like Core Wars. That makes creating and simulating it a lot simpler.
This would be an interesting experiment to do, although I predict AIXI would just kill itself fairly quickly.
Game of Life is Turing-complete.