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> I claim that this asymmetry in my prophetic abilities (100% ability to predict what will be seen on the video vs 50% for re-flipping the actual coin) is a res

by effie 4y ago

> I claim that this asymmetry in my prophetic abilities (100% ability to predict what will be seen on the video vs 50% for re-flipping the actual coin) is a result of the asymmetry between the past and future. No, this and other similar memory-induced asymmetries have much more prosaic reason. It is more successful to predict systems we have enough knowledge and control of (video playback) than those we don't (coin flip). Predicting and retrodicting systems we understand and have memory of is successful, and predicting and retrodicting systems we don't understand and don't have memory of is not. This has nothing to do with universal asymmetry of past vs future. Your memory of what has happened (e.g. some system had lower entropy in past) does not explain why your original argument does not apply now to retrodiction of past macrostates; the memory only contradicts the result of that argument. > If I can reliably predict the outcome of any experiment, that means I know everything that is going to happen before it happens, including my own actions. That would in no way prevent validity of 2nd law.

lisper 4y ago
> It is more successful to predict systems we have enough knowledge and control of (video playback) than those we don't (coin flip). Nope. Consider this variation on the experiment: I flip a coin, I make a video recording, but I do not look at the coin, I only reveal it to the video camera. Now I cannot predict the result of watching the video despite the fact that my "knowledge and control" of my video recorder is exactly the same as before. And, BTW, my ability to make a reliable prediction in the first case is in no way contingent on my knowledge of how video recorders work, nor is it contingent on my having control of the camera. I could be completely ignorant of the inner workings of video recorders, and the camera could be completely outside of my control, and I could still make an accurate prediction, but only if I saw the coin after if was flipped. > That would in no way prevent validity of 2nd law. I never said otherwise, but that is neither here nor there.
- effie 4y ago
  When you do not look at the coin result that gets recorded, your knowledge of the state of the recorder (the record inside) is not "exactly the same as before". You lack information on the state of the recorder that you would have if you looked. Yes, knowledge of details of how the recorder works is indeed largely irrelevant, but that was obvious. The point was that being successful with predictions or retrodictions of some system is correlated with having enough information on its state and the laws it obeys. This difference of success for predicting playback vs predicting result of a future experiment sensitive to unknown conditions is due to sufficient information vs insufficient information. I don't see anything in your responses that shows some universal asymmetry between past and future that would explain why your original argument does not work for past macrostates, but does work for future ones.
  - lisper 4y ago
    > You lack information on the state of the recorder that you would have if you looked. No, I lack information about the state of the coin. All of my observations and knowledge of the operation of the recorder are exactly the same as before. I can still see the camera, see that it is pointing at the location of the coin (even though the coin itself is hidden from me). Nothing has changed in that regard. > I don't see anything in your responses that shows some universal asymmetry between past and future Maybe it would be clearer if I change the scenario slightly: instead of one camera, I'll use N>>1 cameras, all pointing at the same coin. I flip the coin in view of all the N cameras, but hidden from my view, and then I put the coin in my pocket without ever looking at it. At this point I can make no reliable predictions. But if I wach the playback on one of the N cameras, I can then reliably predict the outcome of viewing the playback on any and all of the other cameras. But under no circumstances can I ever accurately predict the outcome of flipping the coin again. Why? Because there is a fundamental asymmetry between the past and future. It is possible to make reliable records of the past, and if you make multiple records of the same event, all of those records will agree on what the outcome was (that's what "reliable record" means). By way of very stark contrast, it is not possible to make reliable records of the future.
    - effie 4y ago
      > No, I lack information about the state of the coin. And that implies you lack information on the record, which is decisive for predicting successfully its playback. > But under no circumstances can I ever accurately predict the outcome of flipping the coin again. Because you lack the necessary information, because you assume those experiments are that way. If you set them up so that you don't look at the coin flip result, but in the next coin flip you measure the initial conditions and the flipping process accurately enough, the conclusion would be the opposite - you would accurately predict the new coin flip, and would not be able to predict the playback. > Why? Because there is a fundamental asymmetry between the past and future. Not at all. The asymmetry is due to how you defined constraints on the experiments. > It is possible to make reliable records of the past, ... it is not possible to make reliable records of the future. Record is, by definition, a pattern that has been created in the past, and this is likely to correlate more with the past states than with the future states. This is a property of the concept, not of some universal asymmetry between past and future. We may introduce analogous concept of a future record, which will be created in the future, and which will correlate with the future states. We can talk instead about prediction and retrodiction. And then this is more of an easy/hard thing, not possible/impossible thing, and the distribution of success on this axis depends on details. Predicting Moon's position on sky 2 years into future is easier than retrodicting it 20 000 years into past. None of this explains why your original argument does not apply to past macrostates.

by effie 4y ago

lisper 4y ago

> It is more successful to predict systems we have enough knowledge and control of (video playback) than those we don't (coin flip). Nope. Consider this variation on the experiment: I flip a coin, I make a video recording, but I do not look at the coin, I only reveal it to the video camera. Now I cannot predict the result of watching the video despite the fact that my "knowledge and control" of my video recorder is exactly the same as before. And, BTW, my ability to make a reliable prediction in the first case is in no way contingent on my knowledge of how video recorders work, nor is it contingent on my having control of the camera. I could be completely ignorant of the inner workings of video recorders, and the camera could be completely outside of my control, and I could still make an accurate prediction, but only if I saw the coin after if was flipped. > That would in no way prevent validity of 2nd law. I never said otherwise, but that is neither here nor there.

effie 4y ago
When you do not look at the coin result that gets recorded, your knowledge of the state of the recorder (the record inside) is not "exactly the same as before". You lack information on the state of the recorder that you would have if you looked. Yes, knowledge of details of how the recorder works is indeed largely irrelevant, but that was obvious. The point was that being successful with predictions or retrodictions of some system is correlated with having enough information on its state and the laws it obeys. This difference of success for predicting playback vs predicting result of a future experiment sensitive to unknown conditions is due to sufficient information vs insufficient information. I don't see anything in your responses that shows some universal asymmetry between past and future that would explain why your original argument does not work for past macrostates, but does work for future ones.
- lisper 4y ago
  > You lack information on the state of the recorder that you would have if you looked. No, I lack information about the state of the coin. All of my observations and knowledge of the operation of the recorder are exactly the same as before. I can still see the camera, see that it is pointing at the location of the coin (even though the coin itself is hidden from me). Nothing has changed in that regard. > I don't see anything in your responses that shows some universal asymmetry between past and future Maybe it would be clearer if I change the scenario slightly: instead of one camera, I'll use N>>1 cameras, all pointing at the same coin. I flip the coin in view of all the N cameras, but hidden from my view, and then I put the coin in my pocket without ever looking at it. At this point I can make no reliable predictions. But if I wach the playback on one of the N cameras, I can then reliably predict the outcome of viewing the playback on any and all of the other cameras. But under no circumstances can I ever accurately predict the outcome of flipping the coin again. Why? Because there is a fundamental asymmetry between the past and future. It is possible to make reliable records of the past, and if you make multiple records of the same event, all of those records will agree on what the outcome was (that's what "reliable record" means). By way of very stark contrast, it is not possible to make reliable records of the future.
  - effie 4y ago
    > No, I lack information about the state of the coin. And that implies you lack information on the record, which is decisive for predicting successfully its playback. > But under no circumstances can I ever accurately predict the outcome of flipping the coin again. Because you lack the necessary information, because you assume those experiments are that way. If you set them up so that you don't look at the coin flip result, but in the next coin flip you measure the initial conditions and the flipping process accurately enough, the conclusion would be the opposite - you would accurately predict the new coin flip, and would not be able to predict the playback. > Why? Because there is a fundamental asymmetry between the past and future. Not at all. The asymmetry is due to how you defined constraints on the experiments. > It is possible to make reliable records of the past, ... it is not possible to make reliable records of the future. Record is, by definition, a pattern that has been created in the past, and this is likely to correlate more with the past states than with the future states. This is a property of the concept, not of some universal asymmetry between past and future. We may introduce analogous concept of a future record, which will be created in the future, and which will correlate with the future states. We can talk instead about prediction and retrodiction. And then this is more of an easy/hard thing, not possible/impossible thing, and the distribution of success on this axis depends on details. Predicting Moon's position on sky 2 years into future is easier than retrodicting it 20 000 years into past. None of this explains why your original argument does not apply to past macrostates.