Machines Who Think FrontMatter.pmd 1 1/30/2004, 12:15 PM Other books by the author: Familiar Relations (novel) Working to the End (novel) The Fifth Generation (with Edward A. Feigenbaum) The Universal Machine The Rise of the Expert Company (with Edward A. Feigenbaum and H. Penny Nii) Aaron’s Code The Futures of Women (with Nancy Ramsey) FrontMatter.pmd 2 1/30/2004, 12:15 PM Machines Who Think A Personal Inquiry into the History and Prospects of Artificial Intelligence Pamela McCorduck A K Peters, Ltd. Natick, Massachusetts FrontMatter.pmd 3 1/30/2004, 12:15 PM Editorial, Sales, and Customer Service Office A K Peters, Ltd. 63 South Avenue Natick, MA 01760 www.akpeters.com Copyright © 2004 by A K Peters, Ltd. All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission from the copyright owner. “Artificial Intelligence”. Copyright (c) 1993, 1967, 1963 by Adrienne Rich, from COLLECTED EARLY POEMS: 1950-1970 by Adrienne Rich. Used by permission of W. W. Norton & Company, Inc. Library of Congress Cataloging-in-Publication Data McCorduck, Pamela, 1940- Machines who think : a personal inquiry into the history and prospects of artificial intelligence / Pamela McCorduck.–2nd ed. p. cm. Includes bibliographical references and index. ISBN 1-56881-205-1 1. Artificial intelligence–History. I. Title. Q335.M23 2003 006.3’09–dc21 2003051791 Printed in Canada 08 07 06 05 04 10 9 8 7 6 5 4 3 2 1 FrontMatter.pmd 4 1/30/2004, 12:43 PM To W.J.M., whose energetic curiosity was always a delight and, at the last, a wonder. FrontMatter.pmd 5 1/30/2004, 12:15 PM “Some of the people are saying the Eight Sages took you away to teach you magic,” said a little girl cousin. “They say they changed you into a bird, and you flew to them.” “Some say you went to the city and became a prostitute,” another cousin giggled. “You might tell them that I met some teachers who were willing to teach me science,” I said. The Woman Warrior: Memoirs of a Girlhood among Ghosts, —Maxine Hong Kingston “Everything should be made as simple as possible, but not simpler.” —Albert Einstein FrontMatter.pmd 6 1/30/2004, 12:15 PM Contents Foreword xi Preface xvii Time Line: The Mechanization of Thinking xxiii Part I Beginnings 1 Brass for Brain 3 Surveys attempts before the twentieth century to create artificial intelligences, both literary and real. Argues that twentieth-century artificial intelligence is only the latest, though the most successful, instance of a long Western tradition, and shares much with its ancestors. 2 From Energy to Information 37 Delineates the early attempts of philosophers, and later psychologists, to define the mind, and the parallel attempts of mathematicians to turn human logic into rigorous mathematics. Shows that the dominant model for these thinkers was from physics, and that not until cybernetics introduced a new model—information in an open system, as opposed to energy in a closed system—could the computer successfully be used as a medium for intelligent behavior. 3 The Machinery of Wisdom 59 Focuses on the computer as a medium for intelligent behavior, with close attention to Alan Turing, a brilliant British logician who helped design one of the first computers and was responsible for much early work in artificial intelligence. Discusses the Ameri- can pioneer John von Neumann, who held a view opposite to Turing’s, that computers would never be able to “think.” 4 Meat Machines 85 Traces the growing conviction that brains are a species of machine, the failed attempts to equate the on-off logic of the computer with the on-off logic of brain neurons. Reviews the early work of McCulloch and Pitts, as well as self-organizing systems, the Perceptron, and other attempts in the United States and Great Britain to link brains and machines. vii FrontMatter.pmd 7 1/30/2004, 12:15 PM viii Contents Part II The Turning Point 5 The Dartmouth Conference 111 Reports on a conference that in 1956 gathered the threads of an assortment of projects with the same general underlying assumptions. Everyone was there, and the conference served as a rite of tribal identification that set patterns for future research and personal relations. 6 The Information-Processing Model 137 Covers the pioneering work of Newell, Shaw, and Simon, which set the tone for the next decade of research. The influence of these men on computing and cognitive psychology so pervades those fields that their discoveries and models are simply taken for granted. 7 Fun and Games 171 Describes how computers were taught to play chess and checkers, and why this devel- opment made IBM so nervous. Analyzes the scientific and social significance of com- puter games. Part III Resistance 8 Us and Them 195 Discusses the critics of artificial intelligence, who give the lie to the idea that science is a disinterested enterprise. Includes some speculations as to why artificial intelligence seems to provoke people to extremes, and covers the first extremist, Mortimer Taube, author of Computers and Common Sense. 9 L’Affaire Dreyfus 211 Considers the bitterest critic of artificial intelligence, who examined the evidence and found it wanting. However, a computer walloped him at chess, and his demands continue to be met. (Or do they?) Dreyfus and his book What Computers Can’t Do are introduced as fixtures in the artificial-intelligence community, and the man is presented as an example of the committed mind that finds only what it expects to find, even as scientists with the opposite commitment find what they expect to find. Relates prophecies, insults, and other scientific high jinks—a case study in the subjective side of science and philosophy. Part IV Realizations 10 Robotics and General Intelligence 243 Investigates the robot and the difficulty of general, as opposed to special-purpose, intel- ligence. Presents two approaches, the General Problem Solver and the Advice Taker, and inspects some of the problems and solutions robot makers have encountered. Fo- cuses on Shakey, the SRI robot, who rolled into the hearts and fears of millions— thanks to some scurrilous publicity. FrontMatter.pmd 8 1/30/2004, 12:15 PM Contents ix 11 Language, Scenes, Symbols, and Understanding 277 Views some of the interesting projects of the 1970s having to do with language, scenes, symbols, and understanding. Concentrates on language understanding, written and spoken, and parallel problems in visual analysis. 12 Applied Artificial Intelligence 317 Examines a here-and-now application of artificial intelligence in DENDRAL, the pro- gram that assists organic chemists, and some of its collateral programs. Looks at the MIT education laboratory, which applies artificial-intelligence principles in a different way. Part V The Tensions of Choice 13 Can a Made-Up Mind Be Moral? 353 Asks the questions: Can artificial intelligence really be created? If it can, should it? Reflects on the moral and ethical dimensions of artificial intelligence. Reviews Weizenbaum’s Computer Power and Human Reason and responses to it. 14 Forging the Gods 381 Appraises the central scientific claim of artificial intelligence: that it demonstrates how symbols can be embodied in a physical system, serving as a key to the understanding of mind as the theory of evolution was to the understanding of biology. Regards artificial intelligence as a bridge between science and art, telling us about ourselves in some startling ways. Speculates as to future directions. Part V Afterword: The Following Quarter-Century of Artificial Intelligence 417 The next quarter-century: from celebrity status to fragmented has-been, and back to solid science; successful robots without symbolic intelligence raise big questions; skep- tics continue to doubt and scientists continue to work at the job; achieving a major AI goal-a machine beats the world’s chess champion-reveals new, more challenging goals; the growing realization that intelligence is both knowledge-based and collaborative; finally, the near future looks promising. Timeline: The Evolution of Intelligence 523 Bibliography 535 Index 547 FrontMatter.pmd 9 1/30/2004, 12:15 PM FrontMatter.pmd 10 1/30/2004, 12:15 PM Foreword Machines Who Think has its own modest history that may be worth telling. In the early summer of 1974, John McCarthy made an emergency landing in his small plane in Alaska, at a place called (roughly translated) the Pass of Much Caribou Dung, so remote a spot he could not radio for help. Fortunately, John was rescued. It occurred to me then that before mortality claimed them, some- body ought to go around and ask these guys who’d begun this odd field called artificial intelligence, what they thought they were doing, and why. Eventually, I appointed myself. Later that summer, John McCarthy, Ed Feigenbaum, and I had lunch at the Stanford Fac- ulty Club, where I proposed my project. Ed, whom I’d approached first, was enthusiastic, but John was less so. It was much too early, he said. There I’d be, waking up in five years and slapping my forehead: If only I’d waited for so-and-so to come on the scene! I should think about doing something else instead (and John had a number of suggestions, most of them much too mathematical for my tastes). But when he saw I would not be deterred, he agreed to cooperate. My husband, Joseph Traub, and I returned from that summer stay at Stanford to Carnegie Mellon in Pittsburgh, where he was then head of the computer science department, and where the faculty included Allen Newell, Herb Simon, and Raj Reddy.