The computer and the brain

136 Pages·2012·0.467 MB·English

by  Von Neumann, John

the computer & the brain

john
von
neumann
the
computer
& the
brain
foreword by ray kurzweil
third
edition
new haven
& london
First edition 1958.
Second edition published as a Yale Nota Bene book in 2000.
Third edition 2012.
Copyright ∫ 1958 by Yale University Press.
Copyright ∫ renewed 1986 by Marina V. N. Whitman.
Foreword to the Second Edition copyright ∫ 2000 by Yale University.
Foreword to the Third Edition copyright ∫ 2012 by Ray Kurzweil.
All rights reserved. This book may not be reproduced, in whole or in part,
including illustrations, in any form (beyond that copying permitted by Sections
107 and 108 of the U.S. Copyright Law and except by reviewers for the public
press), without written permission from the publishers.
Yale University Press books may be purchased in quantity for educational,
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Printed in the United States of America.
Library of Congress Control Number: 2011943281
isbn 978-0-300-18111-1 (pbk.)
A catalogue record for this book is available from the British Library.
Frontispiece: Adapted from ‘‘White Matter Tracks Image #20 from the HCP.’’
Courtesy of Arthur W. Toga and Vaughan Greer at the Laboratory of Neuro
Imaging at UCLA; Randy Buckner, Bruce Rosen, and Van J. Wedeen at the
Martinos Center for Biomedical Imaging at MGH; Consortium of the Human
Connectome Project.
10 9 8 7 6 5 4 3 2 1
the silliman foundation lectures
On the foundation established in memory of Mrs. Hepsa Ely
Silliman, the President and Fellows of Yale University pre-
sent an annual course of lectures designed to illustrate the
presence and providence of God as manifested in the natu-
ral and moral world. It was the belief of the testator that any
orderly presentation of the facts of nature or history con-
tributed to this end more e√ectively than dogmatic or po-
lemical theology, which should therefore be excluded from
the scope of the lectures. The subjects are selected rather
from the domains of natural science and history, giving
special prominence to astronomy, chemistry, geology, and
anatomy.
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contents
Foreword to the Third Edition, by Ray Kurzweil xi
Foreword to the Second Edition, by Paul M.
Churchland and Patricia S. Churchland xxxiii
Preface, by Klara von Neumann xlv
Introduction 1
part 1 the computer 3
The Analog Procedure 3
The Conventional Basic Operations, 4
Unusual Basic Operations, 4
The Digital Procedure 6
Markers, Their Combinations and Embodiments, 6
Digital Machine Types and Their Basic Components, 7
Parallel and Serial Schemes, 8
The Conventional Basic Operations, 8
contents
Logical Control 11
Plugged Control, 12
Logical Tape Control, 12
The Principle of Only One Organ for Each Basic Operation, 13
The Consequent Need for a Special Memory Organ, 14
Control by ‘‘Control Sequence’’ Points, 14
Memory-Stored Control, 17
Modus Operandi of the Memory-Stored Control, 20
Mixed Forms of Control, 21
Mixed Numerical Procedures 22
Mixed Representations of Numbers.
Machines Built on This Basis, 23
Precision 25
Reasons for the High (Digital) Precision Requirements, 26
Characteristics of Modern Analog Machines 29
Characteristics of Modern Digital Machines 29
Active Components; Questions of Speed, 30
Number of Active Components Required, 31
Memory Organs. Access Times and Memory Capacities, 32
Memory Registers Built from Active Organs, 32
The Hierarchic Principle for Memory Organs, 34
Memory Components; Questions of Access, 35
Complexities of the Concept of Access Time, 36
The Principle of Direct Addressing, 37
viii
contents
part 2 the brain 39
Simplified Description of the Function of the Neuron 40
The Nature of the Nerve Impulse 40
The Process of Stimulation, 42
The Mechanism of Stimulating Pulses by Pulses; Its Digital
Character, 43
Time Characteristics of Nerve Response, Fatigue, and Recovery, 45
Size of a Neuron. Comparisons with Artificial Components, 47
Energy Dissipation. Comparisons with Artificial Components, 49
Summary of Comparisons, 50
Stimulation Criteria 52
The Simplest—Elementary Logical, 52
More Complicated Stimulation Criteria, 54
The Threshold, 55
The Summation Time, 56
Stimulation Criteria for Receptors, 57
The Problem of Memory within the Nervous System 61
Principles for Estimating the Capacity of the Memory in
the Nervous System, 62
Memory Capacity Estimates with These Stipulations, 63
Various Possible Physical Embodiments of the Memory, 65
Analogies with Artificial Computing Machines, 66
The Underlying Componentry of the Memory Need Not Be
the Same as That of the Basic Active Organs, 67
ix