Lumifer comments on Computation complexity of AGI design - Less Wrong

6 Post author: Squark 02 February 2015 08:05PM

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Comment author: Lumifer 02 February 2015 09:08:25PM 3 points [-]

Intelligence doesn't operate on the basis of proving things. Intelligence operates on the basis of heuristics and so I find the parallel to NP-complete problems flawed.

For clarity, consider a human from 50,000 years ago and see if the way his intelligence operates has resemblance to solving problems in an NP-complete domain.

Comment author: Squark 03 February 2015 08:05:22PM 0 points [-]

I don't quite follow your reasoning. Consider a Go-playing AI based on a Monte Carlo multi-armed bandit algorithm. A human player can analyze its moves and explain them from the point of view of regular human Go-theory. However this would reveal little about the inner operation of the algorithm.

Comment author: Lumifer 03 February 2015 08:22:27PM 3 points [-]

Actual intelligence operates in the world of seriously incomplete data, fuzzy approximations, good-enough heuristics, and making a lot of mistakes. It is NOT the world of math proofs and hard analytical solutions.

Comment author: Squark 05 February 2015 08:27:26AM 0 points [-]

So you're saying that complexity theory is useless in problems involve approximations, heuristics etc?

For one thing, there is a theory of approximate solutions and average case complexity as well. For another, the beauty of complexity theory is that it puts bounds on your abilities regardless of the methods you use: a complexity bound applies to any algorithm, whether analytical or heuristic.

Comment author: Lumifer 05 February 2015 03:57:54PM 1 point [-]

No, I am not willing to make such a sweeping statement. However I will say that constraints and limitations that the hard complexity theory faces are not necessarily binding in the approximations/heuristics world.

Comment author: JoshuaZ 03 February 2015 12:21:54AM 0 points [-]

On the other hand note that we have conjectures which are stronger than P != NP which taken together do amount to saying that approximation can be tough and that many heuristics will also not be likely to succeed. P=BPP, and the Unique Games Conjecture can both be thought of as variations of that theme.

Comment author: Lumifer 03 February 2015 05:48:25PM 1 point [-]

many heuristics will also not be likely to succeed.

Succeed in which sense? Take the traveling salesman problem. You can't analytically solve it for N in the hundreds. But there are heuristics which give acceptable results and are widely used in practice.

Heuristics are not designed to get you to the optimum. They are, by definition, geared to produce a merely acceptable result.

Comment author: JoshuaZ 03 February 2015 07:09:04PM 1 point [-]

Succeed in which sense? Take the traveling salesman problem. You can't analytically solve it for N in the hundreds. But there are heuristics which give acceptable results and are widely used in practice.

It depends what you mean by acceptable. For many problems, assuming that P != NP, one cannot get approximations beyond a certain amount. In particular, one cannot get approximations which asymptotically approach the optimal. See for more details my earlier comment here.