[extropy-chat] Bayes, crackpots and psi

[Samantha Atkins]

On Dec 19, 2004, at 11:26 PM, Hal Finney wrote:

>
> The analysis Damien posted of disagreement about psi on the basis
> of Bayesian reasoning is OK as far as it goes, but it stops with the
> assumption that people have different priors.  Where did those priors
> come from?  Robin Hanson argues that we shouldn't assume people are 
> born
> with different priors: we are all descendents of a common ancestor and 
> in
> that sense we all have the same priors, with our different paths 
> through
> time and evolution being mere information added to that original set of
> prior beliefs.


How is going all the way back to our common ancestor actually 
meaningful for establishing whether we have in common a set of priors 
actually relevant to the subject at hand?  Surely not every prior 
encountered starting with that common root is relevant to whether ESP 
exists.     I get suspicious when I see this long a stretch for an 
argument.

>
> We see here a good example of apparent sharp disagreement, between
> Damien and Eliezer for example; two people who probably respect each
> other and see each other as making a good faith attempt at being 
> rational
> in their beliefs.  How can they disagree?  Doesn't Damien's deep study
> of the issues lend credibility to his relatively favorable assessment?
> And yet doesn't Eliezer's reputation for careful reasoning give credit
> to his own skepticism?

Actually, neither of these things is directly relevant.   Both of them 
make the discussion more likely to be worth our while to follow though.

>   Like the irresistable force meeting the immovable
> object, it's a paradox.  It can't happen.  One side or the other 
> finally
> has to say, you're being irrational (or at least think it; they may be
> too polite to say it out loud).

It is not really a paradox.  Their degree understanding of the facts of 
the matter and their degree of rationality leads them to different 
conclusions on this subject.   It is possible that one of them errs 
more in either of these areas or even that they both error rather 
equally but along different vectors.   The argument that it is a 
paradox if we have disagreement among rational thinkers assumes both 
perfect rationality  and a perfect understanding of sufficient relevant 
information.   Neither of these is likely to be an absolute.   There is 
thus neither an irresistible force nor an immovable object present to 
fret over.

- samantha