OFF: SETI, ETs

[Paul Mather]

On Thu, 11 Jul 1996, M Holmes wrote:

> Well I dunno. You could use it to predict the ultimate fate of the
> Universe. How much bigger would you want?

The point is, *could* you use it to predict the ultimate fate of the
Universe??  Presume, for a moment, that the state of the Universe is
determined by the interaction of fundamental particles.  To predict a
future state would involve projecting forwards the interaction of those
particles, extrapolated from some known position.  Even if their behaviour
at each step were completely known (thanks to "the theory of everything"),
it would be impossible to simulate such an enormous amount of data
(bearing in mind we'd have to, due to possible sensitivity to initial
conditions).  (Even current weather simulations can only cope with a tiny
fraction of the Earth's available weather data, and we know how good they
are at predicting "the ultimate fate of the British summer".:)  A "theory
of everything"  wouldn't even allow us to predict what Mike Holmes would
be doing in 5 years time, given the aforementioned problems of scale
(even assuming we could sift out the morass of particles comprising "Mike
Holmes" from all those around him).

> Sure. Most of the questions it'd enable us to answer are very much in
> the realms of cosmology and philosophy.

It would answer a couple of questions of philosophy, but not many.  And I
wonder how well such a theory of the microscopic (i.e. how the fundamental
particles exist and interact) would address the macroscopic (and realms in
between).  The big problem about the reductionist quest for "the theory of
everything" is that it tells us very well *how* things work, but not
*why*.  (Plus, it is very difficult to apply at different levels of the
reductionist hierarchy in order to obtain meaningful explanations and
predictions.  I mean, we don't discuss the latest Hawkwind album in terms
of air pressure waves, do we, even though this is what music ultimately
"is" when you reduce it down far enough.)  What is needed is a paradigm that
addresses both in a meaningful way.

Cheers,

Paul.

obCD: Skip James, _Today!_

e-mail: paul at csgrad.cs.vt.edu                    A stranger in a strange land.