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Unless I'm misunderstanding something they are not comparing the reconstructed board state to the actual state which is the straightforward thing you would show
by foobarqux 2y ago
Unless I'm misunderstanding something they are not comparing the reconstructed board state to the actual state which is the straightforward thing you would show. Instead they are manipulating the internal state to show that it yields a different next-action, which is a bizarre, indirect way to show what could be shown in the obvious direct way.
- famouswaffles 2y agoFigure 4 is showing both things. Yes, there is manipulation of the state but they also clearly show what the predicted board state is before any manipulations (alongside the actual board state)
- foobarqux 2y agoThe point is not to show only a single example it is to show how well the recovered internal state reflects the actual state in general —— analyze the performance (this is particularly tricky due to the discrete nature of board positions). That’s ignoring all the other more serious issues I raised. I haven’t read the paper in some time so it’s possible I’m forgetting something but I don’t think so.
- famouswaffles 2y ago>That’s ignoring all the other more serious issues I raised. The only other issue you raised doesn't make any sense. A world model is a representation/model of your environment you use for predictions. Yes, an auto-encoder learns to model that data to some degree. To what degree is not well known. If we found out that it learned things like 'city x in country a is approximately distance b from city y' let's just learn where y is and unpack everything else when the need arises then that would certainly qualify as a world model.
- foobarqux 2y agoLinear regression also learns to model data to some degree. Using the term “world model” that expansively is intentionally misleading. Besides that and the big red flag of not directly analyzing the performance of the predicted board state I also said training a neural network to return a specific result is fishy, but that is a more minor point than the other two.
- famouswaffles 2y agoThe degree matters. If we find auto encoders learning surprisingly deep models then i have no problems saying they have a world model. It's not the gotcha you think it is. >the big red flag of not directly analyzing the performance of the predicted board state I also said training a neural network to return a specific result is fishy The idea that probes are some red flag is ridiculous. There are some things to take into account but statistics is not magic. There's nothing fishy about training probes to inspect a models internals. If the internals don't represent the state of the board then the probe won't be able to learn to reconstruct the state of the board. The probe only has access to internals. You can't squeeze blood out of a rock.
- foobarqux 2y agoI don’t know what makes a “surprisingly deep model” but I specifically chose autoencoders to show that simply encoding the state internally can be trivial and therefore makes that definition of “world model” vacuous. If you want to add additional stipulations or some measure of degree you have to make an argument for that. In this case specifically “the degree” is pretty low since predicting moves is very close to predicting board state (because for one you have to assign zero probability to moves to occupied positions). That’s even if you accept that world models are just states, which as mtburgess explained is not reasonable. Further if you read what I wrote I didn’t say internal probes are a big red flag (I explicitly called it the minor problem). I said not directly evaluating how well the putative internal state matches the actual state is. And you can “squeeze blood out of a rock”: it’s the multiple comparison problem and it happens in science all the time and it is what you are doing by training a neural network and fishing for the answer you want to see. This is a very basic problem in statistics and has nothing to do with “magic”. But again all this is the minor problem.