MileyCyrus comments on A (very) tentative refutation of Pascal's mugging - Less Wrong

0 Post author: Arran_Stirton 30 March 2012 06:43AM

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Comment author: Arran_Stirton 31 March 2012 02:16:12PM 0 points [-]

I'm treating the current state of the universe as a different thing entirely to the mugger's implied hypothesis about how the universe works. Both a program simulating Maxwell’s equations would obviously win out over a program simulating Thor, but in terms of predicting the shape of a magnetic field in a certain spot, that depends on the current state of the universe (at least the parts of the universe relevant to the equation).

Though if this is an invalid line of reasoning for some reason, please let me know, thanks.

Comment author: MileyCyrus 31 March 2012 05:53:58PM 0 points [-]

I have no idea where you're going with this.

Both a program simulating Maxwell’s equations would obviously win out over a program simulating Thor,

You use the word "both" but then refer to only one object. Did you forget to include something?

Comment author: Arran_Stirton 04 April 2012 12:35:47AM 0 points [-]

Sorry I'll try to clarify:

If you want to predict the exact state of a system five minutes into the future you need to know the current state of the system and the laws of that system. Call the current state s and the future state s', the laws of the system are simulated by the Turing machine L. Instead of knowing the state of the system, we only know its laws (or rather we take them as a given).

Then any prediction we make about the future state of the system will restrict the range of value for s' that will validate our prediction. The more specific we are about s' the smaller the range of values it can be. In turn this restricts the range of possible values for s (as L(s) = s') that will give s'.

Because we have no information about the current state of the system all possible states are equally likely, and as such the probability that the system will end up in a particular range of s' is the same as the fraction of s (out of all possible s) that will map there.

This is not in relation to any hypothesis about the laws of the system, but instead the current state of the system. I hope this makes my original argument make more sense. If not I'm sorry; please highlight to me where my explanation is going wrong.