constant3 comments on Many Worlds, One Best Guess - Less Wrong

12 Post author: Eliezer_Yudkowsky 11 May 2008 08:32AM

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Comment author: constant3 12 May 2008 06:50:05AM 0 points [-]

Remember, that-which-exists at any moment does not just consist of a set of worlds, but a set of worlds each with a complex number attached. And that-which-exists in the next moment is - the same set of worlds, but now with different complex numbers attached.

You seem to be talking about the wavefunction, which is a complex function defined over the configuration space (a set of configurations each with a complex number attached). But in that case you seem to be confusing a world with a configuration. A configuration defines only position. (Assuming we're talking about positional configuration space.)

It seems I can save myself some trouble explaining by quoting Eliezer:

A point mass of amplitude, concentrated into a single exact position in configuration space, does not correspond to a precisely known state of the universe. It is physical nonsense.

It's like asking, in Conway's Game of Life: "What is the future state of this one cell, regardless of the cells around it?" The immediate future of the cell depends on its immediate neighbors; its distant future may depend on distant neighbors.

If Conway's Game of Life managed to support a multiverse, then a single universe in this multiverse would not correspond to a cell. It would correspond to some section of the whole pattern quite a bit larger than a single cell - a section which was for the most part causally separated from the rest of the pattern. And this section might move around over Conway's gameboard (or whatever it's called), just as a glider can move across Conway's gameboard.