On page 197 Penrose divides scientific theories into three broad
categories: SUPERB, USEFUL, nad TENTATIVE. (Yes, he uses caps)
The paragraph following this list reads:
Into the SUPERB category must go all those I have been discussing
in the paragraphs preceding this one [that is, relativity - both
varieties - and quantum mechanics]. To qualify as SUPERB, I do
not deem it necessary that the theory should apply without
refutation to the phenomena of the world, but I do require that
the range and accuracy with which it applies should, in some
appropriate sense, be _phenomenal_. The way that I am using the
term `superb', it is an extraordinary remarkable fact that there
are any theories in this category at all! I am not aware of any
basic theory in any other science which could properly enter this
category. Perhaps the theory of natural selection, as proposed by
Darwin and Wallace, comes closest, but it is still some way off.
Anyone who wants to use Penrose as an example of someone "who reject[s]
some aspect of evol[ution]" had better think again!
Ken Smith
===================================================
The following quote from the forward of _The Emperor's New Mind_
may refresh your memory as to the main purpose of the book:
Penrose's book is the most powerful attack yet written
on strong AI. Objections have been raised in past centuries
to the reductionist claim that a mind is a machine operated
by known laws of physics, but Penrose's offensive is more
persuasive because it draws on information not available to
earlier writers.
--- Martin Gardner in the forward to _The Emperor's New Mind_
Indeed, the breadth of topics considered is truly amazing. In the last
chapter titled "Where lies the physics of mind" he has a section
dealing with natural selection in the context of his overall thrust
stated above. He begins this section ...
If we suppose that the action of the human brain, conscious or
otherwise, is merely the acting out of some complicated algorithm,
then we must ask how such an extraordinarily effective algorithm
came about. The standard answer, of course, would be 'natural
selection'.
--- Roger Penrose, _The Emperor's New Mind_
He then goes on to summarize the basic ideas of natural selection as
they would apply to algorithms giving Dawkins (_The Blind Watchmaker_) as
a source for further reading. He continues ...
Even according to my own viewpoint, there would have to be
_some_ truth in this picture, since I envisage that much of the
brain's action is indeed algorithmic, and - as the reader will
have inferred from the above discussion - I am a strong believer
in the power of natural selection. But I do not see how natural
selection, in itself, can evolve algorithms which could have the
kind of conscious judgements of the _validity_ of other algoritms
that we seem to have.
--- Roger Penrose, _The Emperor's New Mind_
He elaborates on this idea further and takes into consideration such
arguments as "given enough time, ...", yet remains unconvinced that
natural selection provides the complete answer to the question
posed in his opening statement.
Another quote that may illustrate his point more clearly ...
Nevertheless, one still might imagine some kind of natural
selection process being effective for producing _approximately_
valid algorithms. Personally, I find this very difficult to
believe, however. Any selection process of this kind could act
only on the _output_ of the algorithms and not directly on the
ideas underlying the actions of the algoritms. This is not
simply extremely inefficient; I believe that it would be totally
unworkable. In the first place, it is not easy to ascertain
what an algorithm actually is, simply by examining its output.
(... deletion of example involving Turing machines ...)
Moreover, the slightest 'mutation' (say a slight change in a
Turing machine specification, or in its input tape) would tend
to render it totally useless, and it is hard to see how actual
_improvements_ in algorithms could arise in this random way.
(Even _deliberate_ improvements are difficult without 'meanings'
being available. ..... )
--- Roger Penrose, _The Emperor's New Mind_
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