X-Message-Number: 27578
Date: Sat,  4 Feb 2006 21:28:10 -0500
Subject: For Robert
From: <>

My old friend Robert joins me in the discussion. I hope retirement 
is treating you well.

>> Not that it has much practical importance at this time, but I 
take mild issue with RBR's statement that criteria of identity 
depend on logic and philosophy, not technology. <<

Of course, I simplify for the sake of people who aren't as familiar 
with these ideas as we are. It would be pointless to discuss 
details that are three levels beyond where most people are at.

To you, however, I would say this: that while the definition of 
identity is a priori determined by logical and philosophic 
considerations, the questions of (a) what properties are relevant 
to subjective experience, and (b) what processes (specifically 
related to methods of preservation) are compatible with the ongoing 
obtainment of those properties. These are scientific questions, not 
logical or philosophical ones. And until they are answered, a 
definitive answer to such questions as, 'How much damage can our 
brains sustain before "revival" becomes, from our subjective, first-
person perspective, identical to death?' will remain out of our 

In a sense, the definition of identity doesn't tell us what we can 
survive (that's a question for science), only what we absolutely 
cannot; for example, I don't survive if my brain is ground up and 
used to grow potatoes, while an accidental copy is created on 
another galaxy by a machine that randomly builds 3x2x1 meter 
objects with atomic precision. The accidental clone is not me. The 
distinction between the copy and me is what identity is all about. 

Identity gives us hard answers to all-important questions such as, 
'Is that cup of coffee I see before me the cup of coffee I set down 
5 minutes ago?' (important because if it is, my colleagues will 
agree to let me drink it; otherwise, all bets are off).
>> As one example, RBR, if I remember correctly, ties his 
definition of  identity to continuity of time and space (apparently 
ruling out quanta of time and space). <<

No, I don't require those properties. I use smooth space-time 
because the definition would be three times more complex if I 
didn't. And honestly, I think just two or three people understand 
my existing definition, among the hundreds who read Cryonet every 

>> They constantly confuse dimensions, coordinates, degrees of 
freedom, and parameters. <<

Aye, sloppiness abounds everywhere.

Richard B. R.

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