Re: Physics is a human construct

[rgrandy@ruf.rice.edu (Richard Grandy)]

> Bob Sciamanda wrote:
>
> > Seriously, I believe that consciousness is a unique phenomenon,
> > presenting a unique modeling problem for science.  I have no problem
> > believing that everything else that I observe in natural phenomena
> > (including the behavior of animals and humans) is in principle
> > describable, modelable and even explainable as the behavior of automata -
> > reducible to molecular interactions.  The one exception is my own
> > directly experienced consciousness.  I cannot even describe this
> > phenomenon in terms of anything else; I have no means of conclusively
> > measuring or proving its existence in another entity; and I can imagine
> > no way in which any theoretical or experimental manipulation of atoms can
> > arrive at the observation: "Eureka! There we have produced
> > consciousness!"  Perhaps the very description of itself demarcates the
> > limitations of the human mind.
> Every time I teach a course called "Mind and Machine" I wrestle with these
> issues.  The text for this course is a little book by John Searle, I
> believe, "Mind and Machine."  Searle's thesis is that what we call
> consciousness comprises more functionality than can be achieved, in
> principle, by a digital automaton or any other digital program.  He sees
> consciousness as the result of the chemical and whatever other physical
> activities may be taking place in the brain; no soul.  Searle, like
> Laplace, has no need for God or the soul.
>
> Goedel, Turing, and Church somewhat independently arrived at demonstrations
> of undecidablilty.  Goedel produced a statement which is formally
> undecidable but true.  How did he come up with such a statememt?  Turing
> showed that there are computer programs which will never halt but cannot be
> formally, i.e. by a prescribable finite sequence of rules, diagnosed as
> such.  How?  He produced one.  These men produced notions which, by
> demonstration, no machine could.
>
> If consciousness is just chemistry and maybe quantum mechanics, it can be
> prescribed by a finite set of rules.  Can't it?
>
>        Charlie


Godel produced a statement which is formally undecidable and true IF THE
FORMAL SYSTEM IS CONSISTENT.  Since Godel did not prove the consistency of
the formal system, what he shows is that "The statement S is true and
undecidable, if the formal system is consistent.".  That latter statement
can be PROVED in the formal system--that result is known as godel's Second
Incompleteness Theorem.
This misstatement of the Godel result has been around at least since Nagel
& Newman's book, *Godel's Proof*, in the late 50s, and was recently
elevated into a bestseller by Penrose, but it is still a mistake.

Turing produced a program and showed that there are inputs for which it
does not halt and that the non-halting character cannot be proved in the
formal system, but he did not SPECIFY any particular inputs that he knew
were not halting and which could not be demonstrated.

Neither Godel nor Turing tell us anything very interesting about consciousness.

Richard Grandy
Philosophy
Rice University