Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

HalFinney comments on Probability is in the Mind - Less Wrong

60 Post author: Eliezer_Yudkowsky 12 March 2008 04:08AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (190)

Sort By: Old

You are viewing a single comment's thread.

Comment author: HalFinney 12 March 2008 06:58:10PM 2 points [-]

I'm not sure the many-worlds interpretation fully eliminates the issue of quantum probability as part of objective reality. You can call it "anthropic pseudo-uncertainty" when you get split and find that your instances face different outcomes. But what determines the *probability* you will see those various outcomes? Just your state of knowledge? No, theory says it is an objective element of reality, the amplitude of the various elements of the quantum wave function. This means that probability, or at least its close cousin amplitude, is indeed an element of reality and is more than just a representation of your state of knowledge.

For aficionados of interpretations of QM, this relates to an old debate, whether the so-called "Born rule" can be derived from the MWI. Various arguments have been offered for this, including one by Robin, and some have claimed that these now work so well that the argument is settled. However I don't think the larger physics/philosophy community is convinced.