X-Message-Number: 7896
Date:  Wed, 19 Mar 97 12:29:04 
From: Mike Perry <>
Subject: digital vs. analog, movies

Here are more comments relating to uploading. The worry 
is expressed that we are straying from cryonics in such discussions, 
but I think they are relevant to our general theme of how to 
perpetuate our existence, which is what cryonics is about too.
Here I'll address two issues that have been raised by Thomas 
Donaldson and others.

One is the idea that "the world is 
not digital," which includes persons. A person simulated
in a computer would therefore fail to really be that person in
any reasonable sense; the range of experiences, etc. possible in
this domain would necessarily be more 
limited than in the real world. However, as I've said before, based 
on physics, the world is digital after all. Based on the Beckenstein 
bound for quantum systems with finite spatial extent and energy 
content, Tipler arrives at around 10^45 bits for the size of the "message" 
that completely characterizes a human being at the quantum level. If 
we raise 2 to the power of this number, we come up with the maximum 
number of states a human being could ever be in (barring the future 
possibility of brain augmentation). It is finite, and the 
idea that we are analog devices capable of a continuum of different 
states is an illusion caused by the overwhelming number of different 
states involved. We really are digital--along 
with everything else in our world. (In fact it is highly unlikely
that all the quantum states are significant for the human being;
Tipler estimates the brain's real information capacity at around
10^15 bits, which is echoed more or less by others. This is still
a big number but much closer to the capacity of our existing
computers.) 

The other issue, which Thomas raises, is that a computer simulation 
of a person would be like a movie--no real consciousness involved. 
And I can see how this would come up. If the computer's actions 
were based simply on reading a disk file containing precomputed 
information, for instance, its actions
would be very like a movie--in fact it would 
be a kind of movie. But the computer could also interact with the 
outside world, and the characters inside could communicate with you 
or me, who would supply unpredictable input which they would have to 
decide how to respond to.  Under those conditions I see no reasons 
why their "consciousness"--if they were convincing about it--would 
have to be considered inauthentic or "not real."

But let's look closer at that "movie." If I could "run" 
a simulated person entirely from precomputed data, could that 
simulation experience feeling? Well, in dreams people experience real 
feeling (though they are not fully conscious). The dream sequence 
must be generated by a part of the brain over which the subject 
has no or only limited control; events seem to be happening as they 
do in real life. Presumably there is some brain mechanism that 
supplies these "events." Such a device could just as well be a 
piece of fancy hardware we have made. I think too that the impulses that 
create the illusion of real events, though probably generated at 
random on the fly (partly at least) could just as well be 
read from a precomputed file. The person experiencing the dream 
would not know the difference (if not told beforehand). So in 
this case something very like a movie, with predictable, precomputed 
events every step of the way, would also be a process 
involving some consciousness and real feeling.

Mike Perry

http://www.alcor.org


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