Engineering a Safer World
Engineering Systems
Editorial Board:
Joel Moses (Chair), Richard de Neufville, Manuel Heitor, Granger Morgan, Elisabeth
Pat é -Cornell, William Rouse
Flexibility in Engineering Design, by Richard de Neufville and Stefan Scholtes, 2011
Engineering a Safer World, by Nancy G. Leveson, 2011
Engineering Systems, by Olivier L. de Weck, Daniel Roos, and Christopher L. Magee,
2011
ENGINEERING A SAFER WORLD
Systems Thinking Applied to Safety
Nancy G. Leveson
The MIT Press
Cambridge, Massachusetts
London, England
© 2011 Massachusetts Institute of Technology
All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical
means (including photocopying, recording, or information storage and retrieval) without permission in
writing from the publisher.
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This book was set in Syntax and Times Roman by Toppan Best-set Premedia Limited. Printed and bound
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Library of Congress Cataloging-in-Publication Data
cm. — (Engineering systems)
Leveson, Nancy.
Engineering a safer world : systems thinking applied to safety / Nancy G. Leveson.
Includes bibliographical references and index.
ISBN 978-0-262-01662-9 (hardcover : alk. paper)
1. Industrial safety. 2. System safety. I. Title.
T55.L466
620.8 ′ 6 — dc23
2011014046
p.
2012
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We pretend that technology, our technology, is something of a life force, a will, and a thrust
of its own, on which we can blame all, with which we can explain all, and in the end by
means of which we can excuse ourselves.
— T. Cuyler Young, Man in Nature
To all the great engineers who taught me system safety engineering, particularly
Grady Lee who believed in me. Also to those who created the early foundations
for applying systems thinking to safety, including C. O. Miller and the other
American aerospace engineers who created System Safety in the United States,
as well as Jens Rasmussen ’ s pioneering work in Europe.