From: "Phil Roberts, Jr."
Newsgroups: sci.bio.evolution
Subject: Re: Robot Evolution
Date: Wed, 10 Jan 2007 13:37:54 -0500 (EST)
Tim Tyler wrote:
> Phil Roberts, Jr. wrote:
>>
>>Stripped to its bare bones, I suspect the Godel argument
>>amounts to something like:
>>
>>a. We have reason to believe that Peaono arithemtic is
>> consistent.
>>b. Therefore we have reason to believe that its Godel
>> sentence can not be proven within the system.
>>c. Therefore we have reason to believe that its Godel
>> sentence is "true".
>
> That doesn't mention human beings or machines - and
> thus is not the argument under discussion.
>
> Stripped to its bare bones, the Godel argument amounts to:
>
> * Machines have limits on their truth determining capabilites -
> in particular they cannot consistently assert the truth of
> their own Godel sentence.
>
> * Humans do not have any such limit.
>
> * Therefore, humans can do what machines cannot - so
> they are not equivalent to machines.
>
This could serve as a caricature of the Lucas argument that
"minds are DIFFERENT FROM machines". 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)
[endquote]
I like this, because it presents a view compatible with my
own view (one based on the premise that 'feelings of
worthlessness' are a maladaptive byproduct of the evolution
of rationality) that reasoning is not so much a matter of
following rules as a matter of COGNIZING rules (e.g., "from
outside the system") and with it, the capacity to TRANSCEND
those rules on those occasions deemed reasonable given the
appropriate context (e.g., Parfit's example of rational
irrationality and its implication that rationality may
have a holistic element). I also like it because it's
coming from someone with sufficient authority on the
subject that trying to argue that this is just another
one of those boneheads who doesn't understand the theorem
is going to be a bit of a hard sell, although so far it
hasn't seemed to slow you down all that much. :)
The relevance to biology, as I mentioned previously, is
because it opens the door to the possibility of an
inverse correlation between 'being cognizant' or
'being rational' and 'being determined', and as
such offers a new way out of the theoretical impasse
we have reached in our attempt to develop a
biological explanation of the benevolence and
malevolence extremes we find in human nature --
"the central theoretical problem of sociobiology"
to quote E. O. Wilson. Another way of saying this
is that it opens the door to entertaining the
possibility that, with the introduction of
rationality into nature, psychodynamic mechanisms
may have begun to usurp the older mechanics of
natural selection, much as Dawkins has implied
with his introduction of the term 'memetics' to
serve as a placemarker to help keep us all reminded
of the explanatory abyss we are currently staring
into.
I am occasionally accused of having backtracked on memes; of
having lost heart, pulled in my horns; had second thoughts.
The truth is that my first thoughts were more modest than some
memeticists, including perhaps Dr. Blackmore. For me, the
original mission of the meme was negative...
The original didactic purpose of the meme was the negative one
of cutting the gene down to size. I became a little alarmed at
the number of my readers who took the meme more positively as
a theory of human culture in its own right -- either to criticize
it (unfairly given my original modest intention) or to carry it
far beyond the limits of what I then thought justified. This
was why I may have seemed to backtrack. (Dawkins).
PR
Why We Turned Out Like Captain Kirk Instead of Mr. Spock
The Psychodynamics of Genetic Indeterminism
http://www.rationology.net