# The measure problem in the anthropic principle

The anthropic principle is based upon Bayesian reasoning applied to the ensemble of universes, or parts thereof, conditioned upon the existence of conscious observers. That still leaves us with the problem of determining the prior probabilities. This is the famous measure problem. How is this measure determined in the current cosmology literature?

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Since everyone seems to be in agreement, I'm reopening this and clearing the comments. – David Z Dec 24 '12 at 16:09

## 1 Answer

One approach is there are no a priori probabilities, but every probability is a function of the prior knowledge. See e.g.

BTW, what does mean that "There is $p=\frac{3}{4}$ for the creation of (a very different universe from ours) and $p=\frac{1}{4}$ for the creation of our universe". For me it makes totally no sense, as you can put any probabilities u like (justifying it or not) and it won't change anything.

And going into calculations of phase-space of consciousness beings sounds like a crackpottery (or at least - an unjustified philosophical claim), unless it gives any experimental prediction (or simplifies any theory).

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