RE: Penrose

Ramez Naam (
Tue, 11 Nov 1997 17:14:48 -0800

> From: Hal Finney []
> It's not clear to me that minds and/or neurons can be expressed as
> formal
> systems. Equivalently, there can be no computer program which
> (exactly, exactly) simulates a brain. This is because we do not have
> a full understanding of the laws of physics. It is possible, as
> argues, that actually the laws of physics are nonlocal and/or have non
> algorithmic properties. Therefore his argument does not apply even at
> the
> lowest level of our own brains.
> However, dealing with an upload or an AI is a different matter. Now
> have a full understanding of the substrate which is executing the
> program.
> It is a completely deterministic, mechanical and logical machine, and
> even relatively simple at the lowest level - as little as a dozen or
> opcodes is probably enough to be a universal machine able to run an
> upload, by our current understanding.

Whoa. If we use "we do not have a full understanding of the laws of
physics" as a rationale, then the substrate of an AI is equally suspect
of being a non-formal system.

Penrose's argument strikes me as exceedingly disengenious. It is the
interconnections between neurons (rather than the neurons themselves)
that result in the emergent information processing power of the brain.
Those interconnections operate via molecular-level signaling, not QM.
At some level quantum uncertainty affects everything, including a
"deterministic" AI substrate. But for all practical purposes, a
computer is a formal system, even if quantum fluctuations will cause it
to flip a memory bit every few thousand years. Does Penrose present any
compelling reason to think of the brain differently?