AI and cognitive psychology rant (getting more and more OT - tell me if I should shut up)

[John J. Lee]

Alex Martelli <aleax at aleax.it> writes:
> Stephen Horne wrote:
>    ...
> > True. But perception cannot change reality. Reality is not about
> > perception - it existed long before there was anything capable of
> > percieving.
> 
> You are so WONDERFULLY certain about such things -- including the
> fact that "before" is crucial, i.e., the arrow of time has some
> intrinsic meaning.

Well, I agree that time-ordering is not important.  I think the main
point is simply that reality is (defined as) independent of
perception, which he was illustrating with an example of a case where
perception was (or is, or will be, if you insist ;-) absent, but
reality was present.  This is a somewhat metaphysical claim (though
perhaps the success of science in itself gives it scientific meaning).
It's the only sane metaphysical position to take, though, unless and
until science grinds to a halt.  Anything else is either advocating
giving up on science, or merely playing around with language.


> Physicist J. A. Wheeler (and his peer referees for the "IBM Journal
> of Research and Development") didn't have your admirable certainty
> that "reality is not about perception".

And it's Wheeler who's wrong, I suspect, not Stephen.  And I mean
wrong in his epistemology, not merely wrong about some particular
theory.

[...]
> course, but the most interesting part of this is that, to a theoretical-
> enough physicist, the mere fact that something happens in the future is
> obviously no bar to that something "building" something else in the past.

I don't have a problem with that a priori.


> Now, it IS quite possible, of course, that Wheeler's working hypothesis
> that "the world is a self-synthesizing system of existences, built on
> observer-participancy" will one day turn out to be unfounded -- once
> somebody's gone to the trouble of developing it out completely in fully
> predictive form, devise suitable experiments, and monitor results.
[...]

Not having read the paper, I can't comment on that particular theory.
All I can say is that that there exist many 'zombie' theories in the
area of quantum mechanics and cosmology (and this thing of Wheeler's
has a suspiciously similar smell) which arbitrarily deny the existence
of some part of reality where some other extant theory does not.  If
both theories are of equal explanatory and predictive power (as is the
case with the rival theories of quantum mechanics), the old one is no
longer rationally tenable.  Now, OK, it's not *quite* as cut-and-dried
as that, because the ideas are hard and complicated, so I may simply
be mistaken about the particular theories we're discussing (I'd
certainly be a fool to say that John Wheeler hasn't thought deeply
about these things, or that my understanding of Physics approaches
his).  But it's certainly true that some theories (the Copehagen
interpretation itself, for example, or the Inquisition's explanation
of the motions of the Solar System) that people continue to believe in
are indefensible because they arbitrarily reject the very existence of
some part of reality that another theory successfully explains.  To
quote David Deutsch: "A prediction, or any assertion, that cannot be
defended might still be true, but an explanation that cannot be
defended is not an explanation".


Can't resist another quote from Deutsch ("The Fabric of Reality", in
the chapter "Criteria for Reality"):

There is a standard philosophical joke about a professor who gives a
lecture in defence of solipsism.  So persuasive is the lecture that as
soon as it ends, several enthusiastic students hurry forward to shake
the professor's hand.  "Wonderful.  I agreed with every word," says
one student earnestly.  "So did I," says another.  "I am very
gratified to hear it," says the professor.  "One so seldom has the
opportunity to meet fellow solipsists."


John