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

# Nick_Tarleton comments on Probability is in the Mind - Less Wrong

60 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: 12 March 2008 08:12:49PM 0 points [-]

I have to say that it sure does seem like there ought to be some way to use the notion of frequentist probability to construct subjective probability along these lines.

Assign a measure to each possible world (the prior probabilities). For some state of knowledge K, some set of worlds Ck is consistent with K (say, the set in which there is a brain containing K). For some proposition X, X is true in some set of worlds Cx. The subjective probability P(X|K) = measure(intersection(Ck,Cx)) / measure(Ck). Bayesian updating is equivalent to removing worlds from K. To make it purely frequentist, give each world measure 1 and use multisets.

Does that work?