Date: Sun, 20 Apr 1997 22:47:07 GMT
Subject: M-SCI: Hawking, Penrose, and positivism


Hawking, Penrose, and Postivism

I meant to thank Paul Gallagher and James Farmelant, 
particularly the latter, for their comments. It makes 
an infrequent list like this worthwhile if even only 
occasionally it is possible to check out some points like
this.

On a further browse I decided to succumb. The book is 
admirably short, and surprisingly cheap for a hard back.

It is "The Large, the Small and the Human Mind"

by Roger Penrose with discussion comments from 
Abner Shimony, Nancy Cartwright and Stephen Hawking

Cambridge University Press 1997 ISBN 0-521-56330-5

pp 185 with an 8 page forward by Malcolm Longair 
summarising in intelligible language the main issues
and the state of debate arising from Penrose's
two books "The Emperor's New Mind" 1989 and
"Shadows of the Mind" 1994.



Hawking starts his comments, entitled 
"The Objections of an Unashamed Reductionist"

"To start with, I should say I'm an unashamed reductionist.
I believe that the laws of biology can be reduced to those
of chemistry. We have already seen this happening with the 
discovery of the structure of DNA. And I further believe that 
the laws of chemistry can be reduced to those of physics.
I think most chemists would agree with that.

Roger Penrose and I worked together on the large-scale structure
of space and time, including singularities and black holes.
We pretty much agree on the classical theory of General Relativity
but disagreements began to emerge when we got on to quantum
gravity. We now have very different approaches to the world,
physical and mental. Basically, he is a Platonist
believing that there's a unique world of ideas that describes
a unique physical reality. I, on the other hand, am a 
positivist who believes that physical theories are just
mathematical models we construct, and that it is 
meaningless to ask if they correspond to reality, just
whether they predict observations.

This difference in approach has led Roger to make three claims
in Chapters 1-3 that I strongly disagree with. 

The first in that quantum gravity causes what he calls OR, objective
reduction of the wavefunction. 

The second is that this process has an important role in the 
operation of the brain through its effect on coherent flow through 
microtubules. 

And the third is that something like OR is needed to explain 
self-awareness because of the Goedel Theorem."




I am surprised that Hawking makes no reference to emergent phenomena.
Certainly there is no reference to a systems way of thinking.

As for the list of cordial differences with his old friend,
this seems an eclectic collection. Are they both off the rails?

Chris Burford

London.





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