X-Message-Number: 13311
From: 
Date: Sat, 26 Feb 2000 09:49:40 EST
Subject: information degradation

A quick reminder, concerning the argument over inference of past states of 
degraded systems:

Someone wrote, >From the final state there are multiple initial states which 
could have produced it,<

This and the context were intended to support the contention that it is 
impossible, or at least practically hopeless, to reconstruct a badly degraded 
system such as a brain that has been seriously damaged by freezing and other 
processes.

This argument cannot possibly be resolved to everyone's satisfaction any time 
soon, since the underlying physics is still not agreed upon by the experts. 
But I want to point out, once more, two things:

First, if you really believe that there are multiple past histories, equally 
real, rather than a unique factual past, then to a considerable extent you 
are saying it DOESN'T MATTER whether the reconstruction is high fidelity, 
because almost any old reconstruction will fit one of the equally real pasts. 
This is a philosophical swamp.

Second, our reconstructions are NOT restricted to reverse-trajectory 
calculations on elementary particles or on quantum states, the many-body 
problem reversed in time. There are countless anchor-points, known and 
recorded states, macro- and sometimes micro-, historical landmarks, that 
enormously reduce the dimensions of the problem.  

No one is likely to change his mind any time soon, and many more 
volumes-maybe many more libraries-- will be written on these topics. But my 
guess-for reasons that I will spell out in detail in another venue--is that 
there is a law of conservation of information; information cannot be created 
nor destroyed. It (like energy) can be degraded, but the implications of that 
are not at all clear.

Robert Ettinger
Cryonics Institute
Immortalist Society
http://www.cryonics.org 

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