X-Message-Number: 3909
From: 
Date: Sun, 26 Feb 1995 20:01:42 -0500
Subject: SCI. CRYONICS symbol & substance

A computer is a device that manipulates symbols. It requires some physical
process to do this, but the physical character of the process is not
important. In other words, a computer does NOTHING of importance but
manipulate symbols, after reading or receiving  input and before writing or
presenting output.

Certain (largely unknown) aspects/activities of the brain constitute mind,
and in particular FEELING, the ground of being and sine qua non of
consciousness or life-as-we-know-it. According to the uploaders, mind can
exist--in principle--in any computer, including Turing's paper tape. In other
words, they claim that mind, including feeling, consists of symbol
manipulation and nothing else. They seem to think this is self-evident,
whereas others of us think it is not only not self evident, but very possibly
(at least)  not true. 

One reason it might not be true is that we KNOW that certain types of
"thought" can be imitated fairly convincingly even by relatively primitive
present-day computers/programs, for which no one claims feeling or
consciousness. There seems no reason, in principle, why more advanced
computers--very large and very fast--could not imitate (say) human
conversation with any desired degree of fidelity--while still having no
vestige of feeling or consciousness.  In other words, emulating conversation
is not sufficient to prove the black box is conscious, which suggests that
symbol manipulation may not be enough.

Further, we can postulate possible physical/physiological requirements for
feeling and consciousness. As a very crude possible example, maybe feeling
requires a "self circuit" which consists basically of a kind of standing wave
in/among a set of neurons, the wave being manifested (say) as electric
current. It "likes" certain states and boundary conditions and "dislikes"
others. (The "like" and "dislike" are very literal, because the
conditions/perturbations DEFINE or CONSTITUTE the organism's feeling of
satisfaction or dissatisfaction, pleasure or pain.)

Note that time could be crucial. Perhaps the various parts of the standing
wave signal to each other at the speed of light, but chemistry is also
involved. A physical analog may not be possible, which COULD mean that only
meat can feel, or that only a limited set of physical substrates can support
mind.

The uploaders, of course, can respond that a digital representation is always
possible, and any isomorphism  blah blah blah. But this mantra cuts no ice. A
digital representation is no different, in principle, than an outsider
interpreting or inferring the subject's internal state. I can guess or deduce
your feelings, but that doesn't mean I share them. (I can also attempt to
guess a black box's "feelings" but that doesn't mean it really has any.)

Returning again to the putative possibility of finding a physical analog to
any given physical process, consider ordinary classical elctromagnetic
phenomena.  An electromagnetic wave travels at the speed of light in vacuum,
the electric and magnetic fields are at right angles to each other and to the
direction of propagation, Maxwell's equations are satisfied, etc. Does--or
could--any other physical phenomenon share these attributes? Probably not, in
which case an e.m. wave can do things that nothing else can do, INCLUDING
certain types of information processing in real time and space.

One of the things that makes the information paradigm so deceptively tempting
is that the brain itself only knows the outside world through interpretation
of symbols. My inner life (the only kind that matters) consists of just two
basic parts: first, my feelings; and second, my computations and memory that
reflect sensory input with feedback from and to feelings. It would probably
be possible to replace many computational aspects of the brain with equally
efficient black boxes, and the self circuit would not know the difference.
But it may NOT be possible to replace the subjective circuit itself with
ANYTHING that will fill the bill. 

Forgive the rambling; have I said anything different or more persuasive?

Robert Ettinger

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