# [extropy-chat] what is probability?

Jef Allbright jef at jefallbright.net
Mon Jan 15 17:11:38 UTC 2007

```Russell Wallace wrote:

On 1/15/07, gts <gts_2000 at yahoo.com> wrote:

An urn contains 100 green and/or red marbles in unknown proportion. We
want to know pr(green) (the probability of drawing a green marble).

Do we? I don't know about you, but I don't find myself wanting to know the probability of drawing a green marble too often :)

Seriously, that's why I said _practical_ example. If it matters, there should be real world cases that can serve as such. If it doesn't matter, well then it doesn't matter.

I'm busy breaking camp and heading home, but this was too key to pass up.

Over the last several hours I've been back-burner thinking about the impass here, that to me hinges on effective understanding of subjectivity.  I kept coming back to gts facing paradox because of his expectation that there be a completely objective "correct" answer while neglecting the impossibility of specifying the question in completely objective terms.  I kept thinking that it would help him to understand that it's the differerence between asking for the "right" answer and asking for the "best" answer.  Which I think is the point of Russell insisting on a "practical" question, a question that matters, and thus highlights the subjective nature of the process.  It's like thinking of the Principle of Indifference.  With no evidence as to likelihoods there is no information as to what is "right", but as a subjective agent within a necessarily larger context, of course we want to minimize the error and thus choose the central value.  If our own context were actually limited to the context of the problem, then of course zero information would imply zero preference, but as subjective beings, this is never the case.

I suppose that the same people who get stuck on the Principle of Indifference would also get stuck on the Meaning of Life problem.  They are each understandable in the same way.

Paradox is always a case of insufficient context.  In the bigger picture all the pieces must fit.

Or as Eliezer likes to say, "there are no mysterious answers, only mysterious questions."

Well, the weekend's over and there's work to be done...

- Jef

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