imaxwell comments on Timeless Physics - Less Wrong

32 Post author: Eliezer_Yudkowsky 27 May 2008 09:09AM

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Comment author: imaxwell 20 February 2012 06:25:52PM 4 points [-]

Super-late answer!

If you ask about a configuration X, "Where does this configuration come from?" I will point at a configuration W for which the flow from W to X is very high. If you ask, "Well, where does W come from?" I will point to a configuration V for which the flow from V to W is very high. We can play this game for a long time, but at each iteration I will almost certainly be pointing to a lower-entropy configuration than the last. Finally I may point to A, the one-point configuration. If you ask, "Where does A come from?" I have to say, "There is nowhere it comes from with any significant probability." At best I can give you a uniform distribution over all configurations with epsilon entropy. But all this means is that no configuration has A in its likely future.

The thing is, it doesn't make sense to ask what is the probability of a configuration like A, external to the universe itself: you can only ask the probability that a sufficiently long path passing through some specific configuration or set of configurations will have A in * its future, or * its past. The probability of the former is probably 0, so we don't expect a singularity in the future. That of the latter is probably 1, so we do expect a singularity in the past.