4 ms·

> Think about it, I say "you have a 30% chance of winning the game from this position". What does that even mean? If I play well I have a 30% chance of winning?

> Think about it, I say "you have a 30% chance of winning the game from this position". What does that even mean? If I play well I have a 30% chance of winning? If my opponent is of equal skill I have a 30% chance of winning? It's completely uninterpretable. It means that the AI that generated the data has 30% chance of winning, or at least that's what it's trying to estimate.

ZephyrBlu 6y ago
That doesn't make sense in the context of a game though. You can't freeze the game and say "I have a xx% chance to win here", because the state of the game continues evolving over time. The generated value is based on a snapshot of the game and isn't related to the final outcome at all, so I believe saying it's a "win probability" is completely wrong.
- anonymoushn 6y ago
  If I have pocket aces and you have 7-2 off-suit, does a win probability exist for my aces against your 7-2? If Ryu is knocked down and he has to dragon punch to beat a meaty command grab and has to throw to beat an opponet who is attempting to block his dragon punch, and both players are at very low health, and these two options dominate all other options, such that the entire game hinges on a single round of a double-blind guessing game with only two possibilities, does a win probability exist for Ryu?
  - ZephyrBlu 6y ago
    You have created 2 scenarios with very small actions spaces. Most games have enormous action spaces, so you can't easily compute a probability. Take Chess for example. Chess engines evaluate millions of scenarios for every move. They don't generate a "win probability" value though, they evaluate board positions.
    - anonymoushn 6y ago
      > Most games have enormous action spaces, so you can't easily compute a probability. Saying you can't compute something by hand on a single sheet of paper is different from saying it doesn't exist. In Chess, your win probability is either 0 or 1 (you either can force a win or you cannot), but most chess engines have a real-valued estimate of their equity in the game that is between 0 and 1.
      - ZephyrBlu 6y ago
        > but most chess engines have a real-valued estimate of their equity in the game that is between 0 and 1 My understanding is that Chess engines do not evaluate a 0-1 value to representing chance to win. They evaluate the perceived material advantage from the current board position. See: https://www.chess.com/blog/ChessMN16/how-to-read-engine-evaluations https://www.chess.com/blog/ChessMN16/how-to-read-engine-eval...
        deleted 6y ago
        [deleted]
        TylerLives 6y ago
        Why do you think it's unreasonable to interpret the value function as probability? I think chess engines don't do it because of draws, but you could look at a chess position and estimate what are your chances of winning/drawing/losing.
        ZephyrBlu 6y ago
        If the probability of winning was static I would agree that the evaluation function is (Or can be) a prediction of win probability. However, because the probability of winning is clearly dynamic over time, trying to predict that probability is inherently a future prediction of the outcome (I.e. a forecast) rather than the prediction of a value. In that case, it does not make sense to view the evaluation function as probability because a forecast is not the same thing as a probability. I'm looking at this from the perspective of the game. From the perspective of any given state in isolation I agree that it makes perfect sense, but in the context of a game it doesn't. This is why I think that plotting all these values on a chart together and calling it "win probability" is non-sensical. It does give you an idea of the game state, but it's not a probability.

ZephyrBlu 6y ago

That doesn't make sense in the context of a game though. You can't freeze the game and say "I have a xx% chance to win here", because the state of the game continues evolving over time. The generated value is based on a snapshot of the game and isn't related to the final outcome at all, so I believe saying it's a "win probability" is completely wrong.

anonymoushn 6y ago
If I have pocket aces and you have 7-2 off-suit, does a win probability exist for my aces against your 7-2? If Ryu is knocked down and he has to dragon punch to beat a meaty command grab and has to throw to beat an opponet who is attempting to block his dragon punch, and both players are at very low health, and these two options dominate all other options, such that the entire game hinges on a single round of a double-blind guessing game with only two possibilities, does a win probability exist for Ryu?
- ZephyrBlu 6y ago
  You have created 2 scenarios with very small actions spaces. Most games have enormous action spaces, so you can't easily compute a probability. Take Chess for example. Chess engines evaluate millions of scenarios for every move. They don't generate a "win probability" value though, they evaluate board positions.
  - anonymoushn 6y ago
    > Most games have enormous action spaces, so you can't easily compute a probability. Saying you can't compute something by hand on a single sheet of paper is different from saying it doesn't exist. In Chess, your win probability is either 0 or 1 (you either can force a win or you cannot), but most chess engines have a real-valued estimate of their equity in the game that is between 0 and 1.
    - ZephyrBlu 6y ago
      > but most chess engines have a real-valued estimate of their equity in the game that is between 0 and 1 My understanding is that Chess engines do not evaluate a 0-1 value to representing chance to win. They evaluate the perceived material advantage from the current board position. See: https://www.chess.com/blog/ChessMN16/how-to-read-engine-evaluations https://www.chess.com/blog/ChessMN16/how-to-read-engine-eval...
      - deleted 6y ago
        [deleted]
      - TylerLives 6y ago
        Why do you think it's unreasonable to interpret the value function as probability? I think chess engines don't do it because of draws, but you could look at a chess position and estimate what are your chances of winning/drawing/losing.
        ZephyrBlu 6y ago
        If the probability of winning was static I would agree that the evaluation function is (Or can be) a prediction of win probability. However, because the probability of winning is clearly dynamic over time, trying to predict that probability is inherently a future prediction of the outcome (I.e. a forecast) rather than the prediction of a value. In that case, it does not make sense to view the evaluation function as probability because a forecast is not the same thing as a probability. I'm looking at this from the perspective of the game. From the perspective of any given state in isolation I agree that it makes perfect sense, but in the context of a game it doesn't. This is why I think that plotting all these values on a chart together and calling it "win probability" is non-sensical. It does give you an idea of the game state, but it's not a probability.