The Brain As a Computer

472 Pages·1961·7.199 MB·English

by  F. H. George and G. A. Kerkut (Auth.)

OTHER TITLES IN THE ZOOLOGY DIVISION
General Editor: G. A. KERKUT
Vol. 1. RAVEN—An Outline of Developmental Physiology
Vol. 2. RAVEN—Morphogenesis: The Analysis of Molluscan Development
Vol. 3. SAVORY—Instinctive Living
Vol. 4. KERKUT—Implications of Evolution
Vol. 5. TARTAR—The Biology of Stentor
Vol. 6. JENKIN—Animal Hormones—A Comparative Survey
Vol. 7. CORLISS—The Ciliated Protozoa
Vol. 8. GEORGE—The Brain as a Computer (2nd Edition)
Vol. 9. ARTHUR—Ticks and Disease
Vol. 10. RAVEN—Oogenesis
Vol. 11. MANN—Leeches (Hirudinea)
Vol. 12. SLEIGH—The Biology of Cilia and Flagella
Vol. 13. PITELKA—Electron-microscopic Structure of Protozoa
Vol. 14. FINGERMAN—The Control of Chromatophores
Vol. 15. LAVERACK—The Physiology of Earthworms
Vol. 16. HADZI—The Evolution of the Metazoa
Vol. 17. CLEMENTS—The Physiology of Mosquitoes
Vol. 18. RAYMONT—Plankton and Productivity in the Oceans
Vol. 19. POTTS AND PARRY—Osmotic and Ionic Regulation in Animals
Vol. 20. GLASGOW—The Distribution and Abundance of Tsetse
Vol. 21. PANTELOURIS—The Common Liver Fluke
Vol. 22. VANDEL—Biospeleology—The Biology of Cavernicolous Animals
Vol. 23. MUNDAY—Studies in Comparative Biochemistry
Vol. 24. ROBINSON—Genetics of the Norway Rat
Vol. 25. NEEDHAM—The Uniqueness of Biological Materials
Vol. 26. BACCI—Sex Determination
Vol. 27. JORGENSEN—Biology of Suspension Feeding
Vol. 28. GABE—Neurosecretion
Vol. 29. APTER—Cybernetics and Development
Vol. 30. SHAROV—Basic Arthropodan Stock
Vol. 31. BENNETT—The Aetiology of Compressed Air Intoxication and Inert Gas Narcosis
Vol. 32. PANTELOURIS—Introduction to Animal Physiology and Physiologycal Genetics
Vol. 33. HAHN and KOLDOVSKY—Utilization of Nutrients during Postnatal Development
Vol. 34. TROSHIN—The Cell and Environmental Temperature
Vol. 35. DUNCAN—The Molecular Properties and Evolution of Excitable Cells
Vol. 36. JOHNSTON and ROOTS—Nerve Membranes
Vol. 37. THREADGOLD—The Ultrastructure of the Animal Cell
Vol. 38. GRIFFITHS—Echidnas
Vol. 39. RYBAK—Principles of Zoophysiology—Vol. 1
Vol. 40. PURCHON—The Biology of the Mollusca
Vol. 41. MAUPIN—Blood Platelets in Man and Animals
Vol. 42. BRONDSTED—Planarian Regeneration
Vol. 43. PHILLIS—The Pharmacology of Synapses
Vol. 44. ENGELMANN—The Physiology of Insect Reproduction
Vol. 45. ROBINSON—Genetics for Cat Breeders
Vol. 46. ROBINSON—Lepidoptera Genetics
Vol. 47. JENKIN—Control of Growth and Metamorphosis
Vol. 48. CULLEY—The Pilchard: Biology and Exploitation
Vol. 49. BINYON—Physiology of Echinoderms
Vol. 50. ANDERSON—Embryology and Phylogeny in Annelids and Arthropods
Vol. 51. BOYDEN—Perspectives in Zoology
THE BRAIN
AS A COMPUTER
F. H. GEORGE
Department of Cybernetics
Brunei University
PERGAMON PRESS
OXFORD NEW YORK · TORONTO · SYDNEY · BRAUNSCHWEIG
Pergamon Press Ltd., Headington Hill Hall, Oxford
Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford,
New York 10523
Pergamon of Canada Ltd., 207 Queen's Quay West, Toronto 1
Pergamon Press (Aust.) Pty. Ltd., 19a Boundary Street,
Rushcutters Bay, N.S.W. 2011, Australia
Vieweg & Sohn GmbH, Burgplatz 1, Braunschweig
Copyright © 1961 Pergamon Press Ltd.
All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted, in any
form or by any means, electronic, mechanical, photocopying,
recording or otherwise, without the prior permission of
Pergamon Press Ltd.
First edition 1961
Second edition 1973
Library of Congress Cataloging in Publication Data
George, Frank Honywill.
The brain as computer.
(International series of monographs on pure and applied biology.
Division: Zoology, v. 8)
Bibliography: p.
1. Cybernetics. I. Title.
Q310.G43 1973 001.53 73-89
ISBN 0-08-017022-6
Printed in Hungary
TO MY WIFE
FOREWORD TO THE SECOND EDITION
IT IS a special privilege to have the opportunity to revise any book.
Especially is it a privilege in the case of a book which contains some of
the most important ideas that I feel I have had on the subject of cyber-
netics.
The first edition of The Brain as a Computer appeared in 1961 and
the book itself was written over a period of some five years or more prior
to 1961.1 was conscious in reading it afterwards that there were many
things in it that I would have written differently and there were many
emphases that I would have changed in some measure, and above all
I felt that all the different sections had not been 'brought to the boil' at
exactly the same time.
I cannot think that it could have been otherwise since the range of
the book is considerable. One criticism of any such wide-ranging book
is that because of its range it may lack depth and this provides one of the
oldest and most difficult problems in the world to solve, particularly in a
field like cybernetics which covers such a wide variety of topics. The
answer must be that some people must devote their time to as much of the
depth as they can but make their primary target the range of the subject
with a view to integrating different facets of it, while others can concen-
trate wholly on a particular problem, or some particular problems,
while being aware of the general range. I feel clear that I belong to the
first category.
Apart from any methodological doubts which I felt about the first
edition of The Brain as a Computer, there were, of course, obvious
changes going on all the time which made me feel that it would be pleasing
to have the opportunity to up-date the book. At the same time as carrying
out the up-dating I would try to correct some of the errors that I was
aware had crept into the first edition. So it was doubly pleasurable to be
ix
X FOREWORD TO THE SECOND EDITION
invited by Pergamon Press to write this second edition and I have been
given, by the publishers, complete freedom to rewrite the text as I please.
The problem of rewriting itself occupied me for some period of time,
far longer than I expected, since it seemed likely that it would be the
last chance I would get to produce a book in terms of my full breadth of
interests in the field of cybernetics, and with the added advantage of
having done much of the 'donkey work' before. My decisions have been
to try to edit the book from start to finish, eliminating errors, and re-
stating opinions which have now changed, and at the same time main-
taining most of the original information.
Admittedly some of what was included originally would have been
omitted if I had tried to write a new book, but it seemed important to
maintain continuity with the first edition of the book and thus most of
what was there before has remained, and only a few sections have been
eliminated on the grounds that they now seem less relevant than they did
at the time. At the same time I have tried to up-date the various sections of
the book and in particular, I felt that a new chapter was required to
deal with heuristic programming, natural language programming, infer-
ence making and the general field of artificial intelligence, as well as a
new chapter on the theory of games.
In the case of automata theory, and the methodological background of
cybernetics, quite a number of changes have been made and I have taken
a completely new look at the basic description of computers. It seems to
me that, of all the sections, that on digital computers was the most out-
of-date and perhaps this is natural in view of the fast-moving nature of
the subject. This leaves the very difficult sections on physiology and
psychology occupying the central part of the book and also representing
fields with which I have been in less contact in the last decade.
The choice here was to omit them altogether, and this seemed to defeat
the whole purpose of the book, or to make a great effort to catch up with
what has been done in the fields on neurophysiology and experimental
psychology which related to the integrated idea of The Brain as a Com-
puter. I chose the second course and have tried to bring in the latest
information which shows, basically, that there has been little change,
or so it seems to me, in either of these two fields; what has occurred is
only the emergence of a great deal of additional information. Nothing has
happened that substantially changes the principles described and the
views originally expressed.
FOREWORD TO THE SECOND EDITION XI
One further difficulty remained. This is a result of a critic of the first
edition who pointed out that whereas there may have been merit in the
development of neurophysiology and experimental psychology and
cybernetics as an overall integrating factor, this was not, as far as the
book was concerned, wholly successful because the integration had not
been carried through. This I was aware of at the time and recognized
the tremendous difficulty involved in such as undertaking. But having
this second opportunity to produce a new edition I have given my
thoughts to this particular point more than any other single one. To give
a detailed integration at the level, as it were, of the neuron or even at
the level of the stimulus-response in all its ramifications as studied by
experimental psychologists working in the field of cognition, is perhaps
too much to ask. But enough has been done, or so I hope, to make much
clearer the value of providing an integrating factor in the form of cyber-
netics to weld neurophysiology, psychology and mathematics together as
part of the totality of cybernetics on one hand and the behavioural
sciences on the other.
Another feature which I would now want to emphasize, which had not
perhaps been sufficiently emphasized before, was that for me, science
is a contextual matter in which particular questions are given particular
answers. Science, of course, is also concerned with general theory and
a framework in which these questions may be answered, but the idea that
science is to try to discover the nature of reality seems somewhat dreamy-
eyed at this moment in time. As a result, it is important to recognize
that any particular type of activity has a particular purpose, or should
have.
This matter of context is particularly relevant when a mathematician
looks at a book, such as those on cybernetics or biology, and is inclined
to say that mathematically they are trivial. This criticism is largely
based on the fact that the book does not treat the subject as a mathema-
tician would; it does not provide a rigorous edifice of theorems and the
like. The answer is, of course, that the biologists, the cyberneticians and
others who are using mathematics are using it for a different end. They
are using it as a means to clarify their ideas and to short-circuit their
descriptions and to possibly prepare the way for an integration with
mathematics as a descriptive language. Hence they would often look at
mathematical work and say that whereas it may be mathematically
interesting, it supplies nothing of the slightest interest to us in our search
xii FOREWORD TO THE SECOND EDITION
to try to develop our own fields such as biology, cybernetics and the like.
This is a sort of misunderstanding that has been growing in science over
the years and I would like to emphasize that it is absolutely vital to try
to understand the purposes for which we are doing anything at any
particular time and judge its effects in terms of whether it achieves those
purposes or not. There still remains the question as to whether the pur-
poses are sufficiently worth-while but it is at least a separate question
from whether the effort made achieves the purpose.
At the same time as carrying through this job of re-editing and correct-
ing, extending and reformulating with new emphases, it was obvious that
I would wish to extend the bibliography. Once more I followed the
principle of including everything that was included originally in the
bibliography and the book as a whole is somewhat larger than what was
already a large book. The only excuse that I can offer is that it seems to be
a subject that merits it.
I perhaps should add at the very least that I did not for a second
suppose that this is a definitive description of cybernetics. On the contrary,
I think of it as dealing with one of the central aspects of cybernetics,
the extent to which we can use rigorous methods and models, of a self-
adapting and feedback kind, to help us to get a clearer understanding and
a more rigorous formulation of problems involving human and humanlike
intelligence and human and humanlike abilities in general, especially in
the cognitive field.
F. H. GEORGE
CHAPTER 1
THE ARGUMENT
IN THIS book an attempt will be made to outline the principles of cy-
bernetics and relate them to what we know of behaviour, both from
the point of view of experimental psychology and also from the point of
view of neurophysiology.
The title of the book, The Brain as a Computer·, is intended to con-
vey something of the methodology involved; the idea is to regard the
brain itself as if it were a computer-type of control system, in the belief
that by so doing we are making explicit what for some time has been
implicit in the biological and behavioural sciences.
Neither the chapters on experimental psychology, which are explicitly
concerned with cognition, nor the chapters on neurophysiology, which
are intended to outline the probable neurological foundations of cognitive
behaviour, are complete in any sense; they are intended to be read and
understood as illustrative of a point of view. It is clear, from the speed at
which all these subjects are developing, and from the vast bulk of knowl-
edge that we now have, that a detailed analysis would provide a lifetime's
work for many people. The emphasis is primarily on the cybernetic ap-
proach, by which we shall mean simply an attempt to reconsider the
biological evidence in terms of mathematical precision, and with the
idea of constructing effective models as a foundation for biological theory.
This implies no radical departure from much of biological tradition; it is
no panacea, but it provides some indication of the possibility of construct-
ing a somewhat different conceptual framework, especially one allowing
the application of relatively precise methods, not only because of the
need for precision in science and for the positive benefits of quantification,
but also in order to avoid the messiness and vagueness implicit in ordi-
nary language when used for the purposes of scientific description.
Cybernetics is a new science, at least in name; it is a new discipline
1
2 THE BRAIN AS A COMPUTER
that overlaps traditional sciences, and proposes a new attitude towards
those sciences. Although it has had its own historical evolution, the
views of modern cyberneticians are both distinctive and novel. The
word 'Cybernetics' has been derived from the Greek word for 'steersman',
and this underlines the essential properties of control and communi-
cation.
In some respects Cybernetics certainly represents a very old point of
view dressed in a new garb, since its philosophical forebears are the
materialists of early Greek thought, such as Democritus, and the Mecha-
nistic Materialists of the eighteenth century. This ancestry is, however, no
more than the bare evolutionary thread of a materialistic outlook, and we
are not primarily concerned here with the philosophical aspects of its
development. It should, indeed, be quite possible for those who are
radically opposed to the Mechanistic Materialists and their modern
counterparts to accept some part of cybernetics for its methodology and
pragmatic value alone.
We will now outline the main ideas of cybernetics, and say something
of its importance for the behavioural and biological sciences.
Cybernetics might be briefly described as the science of control and
communication systems, although it must be admitted that such a general
definition, while correct, is not very helpful.
Cybernetics is concerned primarily with the construction of theories
and models in science, without making a hard and fast distinction between
the physical and the biological sciences. The theories and models occur
both in symbols and in hardware, and by 'hardware' we shall mean a
machine or computer built in terms of physical or chemical, or indeed any
fabric at all. Most often we shall think of hardware as meaning electronic
parts such as transistors and relays. Cybernetics insists, also, on a further
and rather special condition that distinguishes it from ordinary scientific
theorizing: it demands a certain standard of effectiveness. In this respect
it has acquired some of the same motive power that has driven research
on modern logic, and this is especially true in the construction and appli-
cation of artificial languages and the use of operational definitions.
Always the search is for precision and effectiveness, and we must now
discuss the question of effectiveness in some detail. It should be noted
that when we talk in these terms we are giving pride of place to the
theory of automata at the expense, at least to some extent, of feedback
and information theory.