Wei writes: > Suppose there are only two logically possible deterministic universes A > and B, and you know that A has measure 0.9, and B has measure 0.1. Suppose > that until time T the history of these two universes are identical. At > time T an experiment will be done in both universes. In universe A the > outcome of the experiment will be "a", and in universe B the outcome will > be "b". If before time T you were given an opportunity to bet $10 that the > outcome is "a" at 1:1 odds, so that in universe A you would gain $10, and > in universe B you would lose $10, Would you take the bet?
Measure is not supposed to be just an abstract number that is attached to a universe. It has meaning in terms of our own perceptions and experience in that universe. The all-universe theory includes both a model of universes which exist, and a way of relating our experiences of consciousness to those universes. In the theory, if there is a physical system in the multiverse which is isomorphic to our own mental state, then the probability of experiencing subjective consequences which correspond to changes in that system will be proportional to its measure. This is a crucial linkage for the theory to have explanatory power, otherwise our experiences would not need to have any connection to measure and it would be a meaningless parameter. > The standard answer is yes, you should take it because A has greater > measure. But that assumes you care more about universes that have greater > measure than universes that have less measure. But you could say that you > don't care about what happens in universe A, only about what happens in > universe B, in which case you wouldn't take the bet. So it seems that the > measure only affects your decisions if it enters into your utility > function somehow, and it's not clear that it must. Think of a single-universe model with ordinary probability, where you have a bet with a 90% chance of outcome A and 10% chance of outcome B. Conventionally you should take the bet which maximizes your expectations based on A occuring. But you could imagine someone who only cared about what happened if outcome B happened, and bet on B so that he would do well in that unlikely case. It's rational in a certain sense, but it is going to lead to bad consequences in practice. These two examples are similar in that in each case you have to face the reality that you are likely to subjectively experience outcome A. In the multiverse model that is part of the theory which relates subjective experience to the physical model. You can't escape the fact that the subjective consequences of your actions will be based on measure. So I don't think you can ignore it or treat it as a parameter to be dealt with as you like. Hal
