From: Lee Corbin (lcorbin@tsoft.com)
Date: Tue Jun 18 2002 - 00:27:45 MDT
Concerning the discussion about how certain large integers
and uncountably many reals accurately describe a person as
well as does that person's cryonically frozen body, Hal writes
> It might help to expand the set of Platonic entities beyond numbers.
> For example, perhaps you will agree that geometric figures (triangles,
> squares, etc) have just as much existence as numbers; then perhaps
> geometries themselves: plane, n-dimensional, elliptical, etc.
Absolutely; these platonic elements "exist" in the same sense
that the number 17 exists. (And even the skeptics out there
will concede that they know more about 17 than they do about
certain former presidential contenders.) The *reason* why
ideal triangles exist is because they have identifiable non-
arbitrary properties. Each one has a circumcenter, an ortho-
center, and a Gergonne point. If they're not equilateral,
then they also have an Euler line. All these relations and
properties exist just as surely as you and I exist, IMO.
> Then you might be willing to grant Platonic realism to computer programs.
> A program exists in a certain abstract sense, even if it is never actually
> executed, just as a number exists even if it is never written down.
Quite so: computer programs have exactly the same degree of
existence or reality that very large integers do.
> The program's output and run history are fully defined by the program,
> so they have a certain kind of existence as well, similar to the sense
> in which numbers, geometric shapes, geometries, etc., exist.
Yes; the "run history" (or trace of states, outputs, etc.) has
that same platonic existence that all those other things you
mention do. But there is no information flow, no processing,
no invocation of cause and effect---until they are loaded and
run.
> If computer programs and their outputs, even their execution histories,
> have Platonic realism, then it is easier to see how we could be living
> in such a reality.
Here's where you've made an *enormous* jump. Each of us
individually knows that (following Descartes) he or she
is experiencing at the present moment. We logically,
sensibly, and rationally infer that others are too, but
then, it could always turn out that your brain is in a
jar somewhere, or some vast cool entity is running a
simulation of the 21st century where you're emulated
but everyone else is merely portrayed.
> We know that if we were running as a simulation on a computer
> which existed in the physical world, it would not be possible
> to tell what sort of reality embeds the computer program.
> Maybe Platonic reality is enough.
If Platonic reality were enough, then it would completely
wipe out all our reasons for doing anything. As Greg Egan
hinted at in his absurd Theory of Dust (in Permutation
City), your life will continue (has continued--is continuing)
in timeless platonic space regardless of what happens in
the actual execution. So why save a little girl from Nazis?
Why strive to build a friendly AI? Whether you fail or
succeed, and it's all happening in platonic space anyway
then who gives a shit?
No, the answer is to focus on what we've always known, and
to try to extend the ideas gracefully into the new realms
before us where our knowledge is less certain. Just as we
know that someone stops being conscious when they're frozen,
and will resume experience *only* when they're re-animated,
so piles of computer tape, or intricate patterns of dust
between the stars, or large integers have no experiences
until they get run time.
Lee
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