The Joys Of Flesh

John K Clark (
Thu, 5 Sep 1996 20:57:12 -0700 (PDT)


Thu, 5 Sep 1996 Eugene Leitl <>

>Uploading is impossible on von Neumann machines. Even
>semiconductor lithography is insufficient, dedicated maspar
>molecular hardware is required. Nothing less will serve.

The term "Von Neumann machine" can have 2 unrelated meanings, a computer with
a Von Neumann architecture or a machine that can duplicate itself from raw

>A human equivalent as implemented in molecular circuitry is
>thought in reside in a volume ranging from a sugar cube to
>an orange (with cooling, packaging, interfacing, etc. about
>the size of the fridge), and run at 1..10^3 realtime speed.
> Power burn might lie in kW range. Nanoists will claim much
>better performance in a much smaller package, but I tend to
>be less optimistic,

Using the figure Hans Moravec came up with, 10^13 calculations per second to
emulate the human brain, Drexler determined that an uploaded human mind would
not be very big. Less than an ounce of matter, mostly carbon, and about 15
watts of energy should be enough for an upload, much less if you use
reversible computing. That's cheating a little because you'd also need a
cooling system for the nano computer, but even so, it wouldn't use more
energy than a dim light bulb and would probably weigh less.

If you wanted VR too you'd need a little more power to simulate a rich
environment, an entire virtual world for the upload, but it wouldn't amount
to much, because speed would not be an issue. Even if the computer that was
simulating you and the virtual world was very slow, from your point of view
it would seem infinitely fast. If the machine had performance problems all
you'd have to do is have the part of the computer that was simulating you
slowed down or even stopped, while leaving the part of the computer that
simulated the rest of the universe running at normal speed. Regardless of how
many calculations it would take to convince you that the simulation was real
it could be done instantly, from your point of view. Once the machine was
caught up, our part of the computer could be carefully restarted till the
next speed bottleneck.

>practicablity of strong Drexlerian nanotechnology has not
>been demonstrated yet.

The practicality of nanotechnology has been demonstrated by life. The
practicability of strong Drexlerian Nanotechnology has not been demonstrated
for the simply reason that it is not practical, yet. What Drexler has shown is
that it is an engineering problem not a scientific one, that it, there is no
known physical reason that would make it impossible.

>Anyway, diamond rod logic is too slow in comparison to
>molecular switches, which operate on electronically excited
>molecular states/quantum dot arrays.

Not too slow for an upload. The acoustic speed in a diamond is 1.75 X 10^4
meters per second, pretty slow compared to the speed if light at 3 X 10^8
but very fast compared to the signals the brain uses at about 100 meters a
second or less, sometimes much less. Because they would be so small, diamond
rod logic would be far faster than any electronic logic circuits we have today,
and enormously faster than the old steam powered biological brain each of us
uses today.

Fast as it is I'm sure we can do better. Drexler uses rod logic because it's
easier to design than nanometer electronic logic, and if you want to show a
proof of concept it makes sense to do so as simply as possible.

>>Honestly, am I the only extropian who likes the flesh?

>You might have no choice. You seem to assume that >H level
>intelligences to be actively benign, leaving you a sufficient part
>of resources.

I agree with Eugene. If the >H are nice enough to let us live, it will
probably be in VR. They won't want us using up a lot of resources in the
"real" world and they would probably be a bit squeamish about letting us fool
around at that level of reality, like letting a monkey run around in an
operating room. They'll probably want a firewall to protect themselves from
our stupidity.

John K Clark

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