X-Message-Number: 9173
Date: Tue, 17 Feb 1998 06:45:29 -0800
From: "Joseph J. Strout" <>
Subject: Re: CryoNet #9171 - #9172 (sigh)

Thomas wrote:

>Moreover connections between neurons generally aren't single: there may be
>more than one synapse, and their location may play a role. Furthermore
>if you study what is known about memory you will see that the idea that it
>may consist of the formation of a new connection has wide acceptance, though
>not as a proven fact, but as a very likely result of current research.

And if you, Thomas, have read my posts in the past, then you know that I do
study what is known about memory, and I know well as you that it consists
of the formation (and retraction) of synapses; indeed I have often pointed
this out in support of the idea of uploading (i.e., since memory is largely
structural rather than chemical, the task is simplified).  You and I have
always been cordial, and on the same side of most issues; let's not damage
our relationship and the character of Cryonet by casting aspersions about
the other's knowledge.

The exact form and material of brain emulators is not important to me,
though it is clearly important to you.  I will argue about it no further,
except to defend myself from direct attacks; and then I will be as brief as
possible, since I am sure readers here are tired of this thread.  I will be
happy to continue our speculations privately if you wish, but they are,
after all, only speculations.

>Some additional points: you suggest that we can read off memories from the
>frozen structure. Unfortunately, if that structure is broken and distorted,
>as it probably is from current suspension methods, your readout will also
>be just as broken and distorted. So it is not nearly so simple as you say.

I have never said it is simple.  Not once, I believe.  Except perhaps in
comparison to infiltrating such a brain with nanomachines and repairing
such damage in biological tissue, then rewarming it (though Ralph Merkle's
suggestions on this are quite interesting and merit further study).

>Moreover, you will almost certainly have to know a good deal about how
>brains normally connect: given that the one you're looking at ISN'T normal
>but damaged, just how are you proposing to reconnect it without such
>knowledge?

Again, I have never proposed to do it without such knowledge.  In fact
we'll need a great deal more knowledge than mere connectivity; we'll need
to have all neurons classified and know their typical intrinsic proporties
based on position, morphology and connectivity.  A brain emulator will be
little more than the embodiment of all this general knowledge, configurable
with the pattern of a specific brain.

>And I am saying that if you have that knowledge you will be
>close to knowing how to reproduce those connections in a biological system.

And this is where we disagree.  Your discussion of how this reproduction
might be accomplished is interesting, though it seems to me rather vague.
My proposals apparently seem vague to you.  Perhaps we both know more than
we are telling.  ;)

>Not only that, but your examination, to
>be at all thorough, must involve not just the APPEARANCE of the damage but
>also its CHEMISTRY.

This is not known, and there is some evidence that it is not so.  Chief
among this is the very evidence for the structural basis of memory to which
you often refer.  Add the fact that neurons seem to fall into a hierarchy
of classes, with common intrinsic properties (membrane channel types and
densities, for example) within a class; and one can generally identify the
class of a neuron by position, structure, and connectivity.  With this
general knowledge, we may need only structural information about a
particular brain.

>You say that you do
>not like nanorobots, yet how do you propose to make your pictures of damaged
>brain structure at the required resolution without such devices?

I most frequently propose to use tranmission electron microscopy on thin
sections, though current work in confocal-mode EM would allow the use of
thicker sections.  The resolution is quite adequate, though it provides no
means to repair at the same scale.  Occasionally I also propose proximal
probe technologies, which I consider a bit of a wildcard at this stage.

>First of all, my problem with uploading of any kind comes
>from my desire not to be uploaded into a computer (though someday I might
>be STORED in a computer, inactive). I do not believe that computers can act
>as brains.

This had become apparent, but I thank you for making it explicit.  I
generally try to avoid saying we'd be uploaded into "computers" because
this word is so intimately associated with digital serial-processing
machines, like the ones on our desks.  A brain emulator would almost
certainly be a special-purpose device, built for no other reason than to
emulate a brain; it would certainly have massive parallelism, and almost
certainly contain analog components (as some neuromorphic chips do today).
So in most respects, it would be quite different from what we think of
today as a computer.

>I do not claim that this means that we could not build a
>brain of very different materials. I even think it LIKELY that we can do
>that. But if I understand you, you seem to believe that doing so will
>somehow be NECESSARY.

I believe only that it *may* be necessary, and that if it is, it will be
possible.  This should be a comfort to us all.  To use the sinking-ship
analogy, we now have both a life boat AND a life jacket (though we may
disagree about which is which).

Please believe me that I appreciate the difficulty of the task, including
all the problems of resolution, processing and storage requirements,
mechanical requirements (both for the uploading process and for artificial
bodies), and issues of learning, emotion, consciousness, and personal
identity.  These are not issues to be adequately dealt with in a paragraph
or two; indeed, I have the outline and several chapters of a book on the
subject (which, unfortunately, will have to wait until I complete my
degree).  And this may not be the proper forum to go into such grisly
detail; there is a mailing list devoted to mind uploading.  (Interested
parties should contact me privately for details on that.)

It has been a very interesting discussion, and if I have seemed at all
testy, I do apologize.  Free discourse is what CryoNet is all about, and I
thank you for challenging my ideas, as I hope I have challenged yours.

Warm regards,
-- Joe

,------------------------------------------------------------------.
|    Joseph J. Strout           Department of Neuroscience, UCSD   |
|               http://www-acs.ucsd.edu/~jstrout/  |
`------------------------------------------------------------------'
        [ Help stop spam: http://www.imc.org/ube-sol.html ]

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9173