From: Tim Tyler 
Newsgroups: sci.bio.evolution
Subject: Re: Robot Evolution
Date: Thu, 11 Jan 2007 13:58:19 -0500 (EST)


Phil Roberts, Jr. wrote:

 > But I have been assuming that your disagreement has been
 > with Hofstadter who I quoted as someone who had offered
 > "one of the most lucid statements of the Lucas/Penrose
 > PERSPECTIVE".  Here is a repeat of what started the whole
 > ruckus, and in which I have taken the liberty of including
 > some of Hofstadter's rationale:
 >
 > [quote]
 >
 >   The only way to explain G's [G = Godel sentence]
 >   non-theoremhood is to discover the notion of
 >   Godel-numbering and view TNT [or Peano arithmetic] on
 >   an entirely different level.  It is not that it is just
 >   difficult and complicated to write out the explanation
 >   on the TNT-level; it is IMPOSSIBLE [my emphasis].  Such
 >   an explanation simply does not exist.  There is, on the
 >   high level, a kind of explanatory power which simply is
 >   lacking, in principle, on the TNT-level.  G's
 >   non-theoremhood is, so to speak, an INTRINSICALLY
 >   HIGH-LEVEL FACT.  It is my suspicion that this is the
 >   case for ALL undecidable propositions, that is to say:
 >   every undecidable proposition is actually a Godel
 >   sentence, asserting its own nontheoremhood in some
 >   system via some code.
 >
 >   Looked at this way, Godel's proof suggests -- though by
 >   no means does it prove! -- that there could be some
 >   high-level way of viewing the mind/brain, involving
 >   concepts which do not appear on lower levels, and that
 >   this level might have explanatory power that does not
 >   exist -- not even in principle -- on lower levels.  It
 >   would mean that some facts could be explained on the
 >   high level quite easily, but not on lower levels AT
 >   ALL.  No matter how long and cumbersome a low-level
 >   statement were made, it would not explain the phenomena
 >   in question.  It is analogous to the fact that, if you
 >   make derivation after derivation in TNT [or Peano
 >   arithmetic], no matter how long and cumbersome you make
 >   them, you will never come up with one for G [the Godel
 >   sentence] -- despite the fact that on a higher level,
 >   you can SEE that G is true.
 >
 >   What might such high-level concepts be?  It has been
 >   proposed for eons, by various holistically or
 >   "soulistically" inclined scientists and humanists
 >   that CONSCIOUSNESS is a phenomenon that escapes
 >   explanation in terms of brain-components; so here is
 >   a candidate at least.  There is also the ever-
 >   puzzling notion of FREE WILL.  So perhaps these qualities
 >   could be "emergent" in the sense of requiring
 >   explanations which cannot be furnished by the physiology
 >   alone. ('Godel, Escher, Bach', p. 708)

I had been wondering how on earth you had managed
to conclude that Hofstadter, Dennett and Chaitin
were remotely on the same side as Penrose on
the issue of potential cognitive capacity of
machines.

Those guys normally have their heads screwed on -
and Hofstadter and Dennet are AI proponents, well
known for advocating the opposite viewpoint.

Anyway, I would certainly never have written paragraphs
like those quoted above.
-- 

Tim Tyler