Re: Cryonics and information theory

From: Brett Paatsch (paatschb@optusnet.com.au)
Date: Mon Jul 07 2003 - 03:14:36 MDT

  • Next message: randy: "Re: Cryonics and information theory"

    Eliezer S. Yudkowsky wrote:

    > Harvey Newstrom wrote:
    > >
    > > We have a lot better imaging technology now, and pictures
    > > of patients' brains who have been frozen. The damage is a
    > > lot worse than we thought. The cells shrank and pulled apart
    > > from each other with gaps between them. Where the cells
    > > stayed put, they are disconnected from other cells. Where
    > > the cells stayed connected, they are all pulled together
    > > leaving huge gaps. The structure and positional relationship
    > > between the cells may or may not be recoverable. Some
    > > people have likened this result to "hamburger", under the
    > > analogy that resurrecting a brain in that condition would be
    > > like resurrecting a cow from hamburger.
    > >

    > ...it still looks to me like it would be
    > better to just chop off the head and drop it into a bucket
    > of liquid nitrogen as fast as possible. *Large*-scale freezing
    > damage is irrelevant; you can still connect the dots easily
    > enough. What you want to ensure is that the information, the
    > Shannon information, is still there. I would not be surprised
    > to find even the earliest cryonics patients are resurrectable in
    > toto; it is not necessary that the cells be reparable but that
    > their physical state, when scanned down to the atomic level,
    > contain enough information to extrapolate back the original
    > brain and its relevant high-level information. The critical
    > parameters here are a matter of information theory, not just
    > medicine, and not at all obvious (i.e., how many initial states
    > map to the same post-freezing state, whether critical
    > information is in global patterns or local patterns, whether
    > information makes a distinction in the final molecular state
    > even if the apparent functional characteristics of the neuron
    > have been destroyed).

    What it the state of the art currently in scanning? Its been my
    impression that the atomic level granularity of a scan that I
    imagine to be necessary can only be done by destroying each
    layer in reading it. Is this the case currently?

    Obviously if each layer could be read in slices of a few
    Angstrom without destroying the brain tissue itself you could
    run mulitple parses from multiple directions.

    It would seem to be a relatively simple exercise to drop a
    sheeps brain (comparable in size to the human brain into liquid
    nitrogen) and then see what sort of freezing damage arises
    givin an indication as to whether the information can be
    extracted once we have something approaching the scanning
    technology required. Obviously the data storage requirements
    are going to be a challenge could we now scan non destructively
    say any 5 millimetre cube within a frozen sheep brain and
    store the data?

    - Brett Paatsch



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