[extropy-chat] Bayes, crackpots and psi

[Brett Paatsch]

From: ""Hal Finney"" <hal at finney.org>

> 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.
>
> 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?

They can seem to disagree simply by not having the same degree of
committment to the issue under consideration.  Eliezer seems to have
set the threshold for the sort of evidence that he would require to be
so high that its not likely to be forthcoming. He also seems influenced
by having explored the terrain a bit before and having encountered
fakes which is kind of annoying when it wastes time. I think ultimately
Eliezer is protecting his time.  He has a valid standpoint but not the
only one.

Damien on the other hand seems to be more willing in this case to
accept a lower standard of evidence and to recognize that scepticism
to be a virtue needs to be applied evenhandedly, or its not scepticism
its just another sort of conservatism or bias.  He can see, I think, the
irony of cryonicists and friendly ai researchers almost beating up on
another bunch of minority viewpoint holders with arguments that could
be easily turned back on those that are making them.

I can think of reasons why Damien might be more willing to spend
time allowing lower standards of evidence to impress him than in this
case than Eliezer.  Damien is a writer. An understanding of where
psi could be real and not conflict with science could help him write
interesting books.

Both Eliezer and Damien are in my opinion, rational, informed about
the scientific method and genuine truthseekers but they are not equally
interested in shining the light on the same yet to be illuminated spots.

Both would loose interest in a conversation pretty quickly if they thought
they were conversing with people that were not pretty rational.

>Doesn't Damien's deep study of the issues lend credibility to his
>relatively favorable assessment?

Yes, for me, some.

> And yet doesn't Eliezer's reputation for careful reasoning give credit
> to his own skepticism?

Generally, but Eliezer seems to have blind spots.

> 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).

I don't think this is right. I think that Damien and Eliezer are simply
managing uncertainty differently with respect to this topic.

> Another possibility is that they don't really disagree as much as
> they seem to.

I think this is so.

> It could be that if they were forced to come up with a
> percentage estimate for the probability that psychic powers exist, they
> wouldn't be that far off.

That would be interesting but I don't know that either would be willing
to assign probabilities to classes as wide as "psychic powers". Without
wrestling with what "psychic powers" could mean specifically I think
both would be reluctant to just guess.

Maybe Eliezer would pretend to start with a rough idea that theres a
50/50 chance and then rapidly bring in "evidence" to knock the chances
down such that it became harder for "psychic powers" to be given
credence.

Maybe Damien would do what I'd do and start with the idea that
if some psychic powers of any strength could exists then the probability
is greater than zero but unclear and work from there bringing in evidence.

I don't know.

>  Maybe it is merely a matter of perspective,
> the glass being half full or half empty.  So I'd be interested to
> hear estimates of the probability, from those who are willing to make
> a serious, unbiased and rational analysis based on the information
> available to them, including (of course) knowledge of other people's
> opinions on the subject.

I'd be interested to see Damien and Eliezer try to come up with a
way to agree thats rational and would allow exploration to continue.
I'm curious to see if your notion of Robins ideas about priors helps.

I suspect Eliezer would be reluctant to play along with this because he'd
not want to spend the time. This is an area more interesting to Damien.

I don't mean to psychoanalyse either Eliezer or Damien. I do agree with
you Hal and apparently Robin, that this sort of apparently disagreement
between rational people is interesting and I am interested in seeing if ways
can be found to make progress using this as an instance of a wider class
of phenomenon.

Brett Paatsch