X-Message-Number: 3895
From:  (Eli Brandt)
Subject: Re: CryoNet #3882 - #3891
Date: Thu, 23 Feb 1995 13:18:21 -0800 (PST)

> From: John K Clark <>
> Subject: SCI.CRYONICS Uploading
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> 
> Bruce Zimov" <> Wrote:
> 
> 		>Why can't the simplest part of the mind change in N ways? 
> 	
> Because then it could be replaced by something that had the
> integer value of (1 + the logarithm base 2 of N) number of
> subparts that change in only one way, so it couldn't be the
> simplest part.

Huh?  If the simplest part of the brain is, as postulated, an N-state
device, then... that is the simplest part of the brain.  You're saying
that it's equivalent to a bunch of 2-state devices, and going from
there to claiming that it actually is that bunch of devices.  If I
show you a die, will you tell me it's three coins?

The brain is also isomorphic to a very big number along with a
function from the naturals to the naturals.  It's isomorphic to an
infinity of different things.  I think you would say that any isomorph
is an acceptable replacement, while some others are not sure of this.

> 		>way.THAT is a switch, and I agree that we can use switches 
> 		>to replace brain parts. BUT THAT is not a bit of information.
> 		
> Well it is, but I don't want to be pedantic, I know your using
> words like "bit" and "information" in non standard ways.

Again: huh?  The switch *is* a bit?  I think this isomorphism/identity
issue needs to be addresses if this discussion is to go anywhere.


> Message #3890
> Date: Wed, 22 Feb 1995 21:20:27 -0800
> From: John K Clark <>
> Subject: SCI.CRYONICS Uploading

> The only other thing I can figure your talking about is the
> cabal properties of dendrites, that is the passive spread of
> electrical signals with no amplification from voltage gated
> channels. Trouble is dendrites make terrible cables,

They're good enough over the span of a small dendritic tree.  Passive
transmission *does* happen in the brain.  In fact, it's the
predominant sort of dendritic transmission.  Any neurophysiology book
should cover this, and I think the low-level discussion of uploading
would benefit from understanding low-level neural processes.

> That's true, but  I'm sure you know there are 2 types of
> channels, voltage gated ion channels and ligand gated ion
> channels.

There's a third: the gap junction.  This is not a gated channel at
all; it's a direct ionic coupling.  As such, it's much faster than an
electrochemical synapse, but doesn't do much information processing.
But if you're talking about passive potentials, you can't ignore
electrical synapses.

> that signals can not be processed and transmitted from the
> synapses to the axon hillock at anything close to light speed
> and could benefit from a speed up as much as the action
> potential would.

Conduction in salt water isn't light-speed fast, but I fail to see how
you're going to speed it up much.

   Eli   



Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3895