[extropy-chat] Cryonics questions...

[Eugen Leitl]

On Tue, May 09, 2006 at 08:07:42PM -0700, spike wrote:

> Another possibility my custom version of Kurzweil's notion of inloading.

Kurzweil has nothing to do with it. See http://en.wikipedia.org/wiki/Mind_transfer
for some of the references. The idea itself is straightforward, similiar
to cryonics. Many people have came up with it independently.

> A brain is about a couple of kilograms and 12 grams of carbon is 6E23 atoms
> and a brain is mostly carbon, so 2000 grams of that is about 6E23/12*2000 =

The brain is mostly water, not carbon. But, it's good enough for a
back of the envelope estimate.

> 1e26 atoms.  Wikipedia says that a human brain has about 100 billion
> neurons, and each of those has a bunch of synapses.  So 1E11 neurons in 1e26
> atoms makes 1e15 atoms per neuron, a million billion atoms per neuron if you
> prefer.  The fact that a bunch of these neurons do stuff that I would no
> longer need if I had no body gives us conservative BOTECs.

But you don't know which processes are relevant, and which are not.
For instance, you might think that you don't need a gentic model,
nor to simulate the mechanical properties. Unfortunately, both
are essential for long-term changes. If you're only tracking ~s
range processes you'll wind up with an extreme Korsakoff patient
(or 50 first dates).
 
> I have a notion that at some future time, nanobots of perhaps a million
> atoms each could enter a frozen brain, not at liquid nitrogen temperatures

I 10^9 atoms is a truly primitive machine. You need about a cubic micron
to build something interesting.

> but perhaps a few tens of degrees below zero celcius so that they have a

No, you have to stay below -130..-150 C. I would actually work at -196
or below.

> solid medium in which to work.  These might tunnel in thru the blood vessels
> all the way down to the capillaries, perhaps removing the now unnecessary

Why would you want to tunnel? You could just cut up everything in nice
manageable slices, and process them.

> blood cells.  They would enter the brain cells and join together to form
> nanocomputers, perhaps a million nanobots per cell.  The million nanobots in
> the cell would perform a calculation that simulates the workings of that
> cell.  

Wouldn't work. I also don't understand why you're doing an incremental
in-situ substitution -- that's something you would do with a live critter.
But if a live critter croaks *now*, you're only option is to freeze
her.
 
> The nanobots would build conductors, perhaps out of nanotubes, to carry
> signals between the neurons.  The nanobot constructed nanocomputers within
> the brain would stay in place, simulating that brain.  If the nanobots were
> made of carbon and each nanobot has a million atoms and each of the hundred
> billion neurons had a million nanonbots, that is 1e6(carbon atoms per
> nanobot)*1E11(neurons)*1E6(nanobots/neuron) = 1E23 carbon atoms, which is
> about 2 grams of carbon.  

If you want to build a hybrid system, you just inflate the volume (straightforward
coordinate transformation) and fill in rest with nanoware. You can do the
same when invading your brain in vivo with several liters of nanoware.
You'd bloat like a superhydrocephalus, but if you do it slowly the cells 
would adapt.
 
> If each neuron has a thousand synapses and the nanotubes for each synapse
> requires a billion carbon atoms to make a conductor that does what synapses
> do, then 1E11(neurons)*1E3(synapses/neuron)*1E9(atoms/synapse)=1e23 carbon
> atoms, which is another 2 grams of carbon.
> 
> In this scenario, 4 grams of nanobots could infiltrate a frozen brain and
> simulate it in place as an inload.  Interestingly, this would allow signals

No can do, chief. Try with several kg, and none of the volume needs
navigation, propulsion, power. Volume wasted -- all you need is computation.

> to go down the neck to a robot body, as it did back when that head guided
> and rode about atop a meat body.  The head would need to remain frozen below
> water ice temperatures, but this would allow that head to go places that we
> cannot go, such as Mars.

Why do you need the head if you've got an isofunctional substitute?
 
> Granted this describes remarkable technology, but is not our current
> technology remarkable compared to that which Thomas Jefferson had at his
> disposal?

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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