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I don't like the framing. AlphaZero is just a very refined and efficient form of brute force. Precomputing weights obtained by brute force doesn't make the over

• falcor84 8y ago
  In what way is it brute force? Obviously it's physically infeasible to store the best move for every position. AlphaZero statistically learns a way to recognize the gist of positions in ways that were previously not possible; I see this as a great achievement.
  • ikeboy 8y ago
    It's a great achievement but I don't think framing it as thinking akin to humans is a valid framing. >AlphaZero gives every appearance of having discovered some important principles about chess, but it can’t share that understanding with us. No, it doesn't have any new principles, it just has a very good system of weights. Imagine a perfect computer that plays the game by mapping out every single move. AlphaZero is a series of optimizations that allow for an efficient but lossy simulation of such a computer. Most of the research in this area is about making an oracle more practical/more accurate estimations of the theoretically correct response. I think it's fair to call it brute force with optimizations.
    • lern_too_spel 8y ago
      You could say the same about the way humans have learned to play chess. The main lines of the popular openings have been exhaustively searched. The way humans evaluate the middle game is also due to distilling features from brute force play and passing them on to other players who add on their own features and compute weights from additional brute force play. The difference between AlphaZero and StockFish is that StockFish only does the latter (compute weights for features given to it by others), while AlphaZero also does the former (distill features from game state).
      • ikeboy 8y ago
        The difference is humans have principles. A good analogy is intuition. If someone says AlphaZero has developed a strong intuition for chess, I have no issue with that, and to the extent human chess is based on intuition comparison is fair. But to portray humans as having chess principles, then say AlphaZero has new ones but just can't describe them seems off. To put it another way, humans have general intelligence and AlphaZero doesn't. At least some of the general intelligence is used for human chess play, so there is a dimension of that which AZ doesn't have.
        • lern_too_spel 8y ago
          In the context of playing chess, humans use general intelligence to featurize the game state in terms of piece value and position value and weight the relative importance of those. The rest is memorization and simulation, which is where the intuition of advanced players comes from — they aren't actively thinking of piece value and position rules like beginmers. I don't see a huge difference here between humans and AlphaZero in those terms.
          • ikeboy 8y ago
            I think using general intelligence to do that is importantly different from simulating a huge number of games and generating weights from that
            • pashamur 8y ago
              If you look at the progress graph of AlphaZero / LeelaChess (open source clone), and look at how it plays in its weaker iterations, it actually pretty closely correlates to how a weaker human chess player would play at those levels of strength (positional blunders, simple tactical mistakes, etc). I've played chess for many years and I've played a few games against Leela (not full strength, the early versions). I never got the feeling that I was playing a computer. Additionally, one of the primary ways of improvement past the ~2000 level is review of master games. Most people who make it to GM level have reviewed upwards of 5,000 master games or more over a significant period of time. So they build up a similar system of "weights" in their mind for different positional features, very similarly to the way the NN would approach the problem. Sure, AlphaZero/Leela has not obtained generalized intelligence, but within a constrained sphere (Chess, Go, etc), it has come just about as close as is possible to that.
    • ganeshkrishnan 8y ago
      Probably. its almost like a "poor man's hash" where you can retrieve the "almost similar best response" for each move. It stores all the games it has self-played in it's network and then looks up best move based on that
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• soraki_soladead 8y ago
  In your comment here and below it sounds like you're saying: "if you take a brute force algorithm and make it more efficient than brute force by not brute forcing the solution then it's just a brute force algorithm!" If AlphaZero is brute force than any use of a non-exhaustive planning mechanism (pruned MCTS in this case) is brute force which is honestly ridiculous. Search and planning have a long history in both computer science _and_ neuropsychology because that is what we call the methods that are more efficient than brute force at the expense of some accuracy. There are some problems with the article but it isn't that AlphaZero is just some overhyped brute force algorithm.
  • ikeboy 8y ago
    I never suggested it's overhyped. I think the specific terms being used to compare it to humans are inaccurate. On a related note, AlphaZero used quite a lot of processing power - even with the optimizations, if it had to run on human hardware it would be pretty worthless.
    • lern_too_spel 8y ago
      > AlphaZero used quite a lot of processing power It ran on a single machine with four TPUs. In a few years with a few more optimizations, I can imagine an equal strength implementation on a handheld chess computer. If you're talking about training hardware, the correct comparison is against the processing time used by all serious human chess players through history because an apples to apples comparison would have both training from scratch (just the rules).
  • ikeboy 8y ago
    If we had a halting oracle and used it to output the best move for any situation, I would also call that brute force, even if it's actually only computing a handful of bits per move. Compressing a computation doesn't change the nature of what's being done meaningfully.
    • soraki_soladead 8y ago
      Your understanding of what brute force means is incorrect. It is an exhaustive algorithm. Any non-exhaustive algorithm is no longer brute force. An algorithm (like AlphaZero) that can locally generalize, even to small degrees, is also not brute force. Your argument is that a brute force algorithm is simply being compressed by a neural network but that isn't how AlphaZero works at all. You can't prune a brute force algorithm's branching and still call it brute force. In fact, if it was, then games like Go wouldn't be approachable by the same algorithm.
• starbeast 8y ago
  >AlphaZero is just a very refined and efficient form of brute force. As is evolution.
  • mannykannot 8y ago
    You have a point, but evolution is regarded, on both sides of the divide, as being the antithesis of intelligent design.
    • starbeast 8y ago
      Maybe. Is very good at designing intelligence however.