Re: Similarity of Structure

From: Lee Corbin (
Date: Tue Mar 18 2008 - 22:33:23 MDT

Matt writes

> [Lee had written]
>> Suppose that by some *obvious* [1] isomorphism,
>> today Lee is one bit string
>> 11011011001110010110111111001010110100000011...
>> and tomorrow I am
>> 11011011001110010110011111001010110100000010...
>> where two 0's happen to be changed to 1's. By all measures
>> of similarity, those two strings are still very similar. (It would be
>> easy to mention some particular measures used by mathematicians,
>> but the ones I'm completely familiar with without having to go look
>> them up aren't very applicable here.)
> Perhaps I am missing the point of this discussion, but the standard way to
> measure the difference between two strings x and y is K(x|y) + K(y|x) where
> K(x|y) is the length of the shortest program that inputs y and outputs x.

Thanks Matt! Hopefully if I had gone and tried to look up that
stuff, I would have encountered that vastly more compact and
simpler notion of similarity between strings.

What do you think of pushing that idea for 2D patterns on a Life Board?
(Easy, I would suppose.) What about for two grains of salt? Think that
it can consistently and advisably be stated also in terms of Komolgorov
complexity? What about large 3D or 4D objects in general?

> Also, what is the conceptual difficulty of having the memories of two people
> who lived separate lives?

Well, that's for another thread, but let's briefly consider two cases.

1. The two people in question are Julius Caesar and George Patton.
    In this case, the sudden merger (merged guy) is baffled and very
    confused. But then, rather easily I suspect since each was a bit
    of a mystic by our standards, the Patton memories would be used
    to formulate the hypothesis that he was really the incarnation of
    Julius Caesar, (a thought that would not displease him in the least,
    I think). The problem could be minimal, except for certain values,
    like, "should all the inhabitants of certain conquered territories be
    exterminated for the sake of future safety"? But hell, that happens
    to all of us (well, not so graphically, or literally, of course). Whenever
    you act in a certain way for a specific reason, you may recall that a
    some time earlier in your life (or earlier in your day) that you acted
    in the opposite way.

   Now this is the *conceptual* difficulty, as you asked. The practical
   difficulty, as when we discussed merging Shakespeare and Einstein,
   would still be enormous.

2. The two people led concurrent lives, and perhaps had opposing
    goals, mutual hatred, and so on. You could end up with a very
    distraught, confused, and possibly mentally ill patient on your

(if you reply to that last part, why don't you merge it back into
the Memory Merging thread? thank you)


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