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Hardcover | $36.00 Short | £29.95 | 232 pp. | 6 x 9 in | August 2010 | ISBN: 9780262014625
Paperback | $24.00 Short | £19.95 | 232 pp. | 6 x 9 in | August 2013 | ISBN: 9780262525176
eBook | $17.00 Short | August 2010 | ISBN: 9780262290289
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Humanity's End

Why We Should Reject Radical Enhancement


Proposals to make us smarter than the greatest geniuses or to add thousands of years to our life spans seem fit only for the spam folder or trash can. And yet this is what contemporary advocates of radical enhancement offer in all seriousness. They present a variety of technologies and therapies that will expand our capacities far beyond what is currently possible for human beings. In Humanity’s End, Nicholas Agar argues against radical enhancement, describing its destructive consequences.

Agar examines the proposals of four prominent radical enhancers: Ray Kurzweil, who argues that technology will enable our escape from human biology; Aubrey de Grey, who calls for anti-aging therapies that will achieve “longevity escape velocity”; Nick Bostrom, who defends the morality and rationality of enhancement; and James Hughes, who envisions a harmonious democracy of the enhanced and the unenhanced. Agar argues that the outcomes of radical enhancement could be darker than the rosy futures described by these thinkers. The most dramatic means of enhancing our cognitive powers could in fact kill us; the radical extension of our life span could eliminate experiences of great value from our lives; and a situation in which some humans are radically enhanced and others are not could lead to tyranny of posthumans over humans.

About the Author

Nicholas Agar is Reader in the Philosophy Programme at Victoria University, Wellington, New Zealand. He is the author of Humanity’s End: Why We Should Reject Radical Enhancement (MIT Press).

Table of Contents

  • Humanity’s End
  • Life and Mind: Philosophical Issues in Biology and Psychology
  • Kim Sterelny and Robert A. Wilson, editors
  • Cycles of Contingency: Developmental Systems and Evolution
  • ,
  • Susan Oyama, Paul E. Griffiths, and Russell D. Gray, editors, 2000
  • Coherence in Thought and Action
  • ,
  • Paul Thagard, 2000
  • Evolution and Learning: The Baldwin Effect Reconsidered
  • ,
  • Bruce H. Weber and David J. Depew, 2003
  • Seeing and Visualizing: It’s Not What You Think
  • ,
  • Zenon Pylyshyn, 2003
  • Organisms and Artifacts: Design in Nature and Elsewhere
  • ,
  • Tim Lewens, 2004
  • Molecular Models of Life: Philosophical Papers on Molecular Biology
  • ,
  • Sahotra Sarkar, 2004
  • Evolution in Four Dimensions
  • ,
  • Eva Jablonka and Marion J. Lamb, 2005
  • The Evolution of Morality
  • ,
  • Richard Joyce, 2006
  • Maladapted Psychology: Infelicities of Evolutionary Psychology
  • ,
  • Robert Richardson, 2007
  • Describing Inner Experience? Proponent Meets Skeptic
  • ,
  • Russell T. Hurlburt and Eric Schwitzgebel, 2007
  • The Native Mind and the Cultural Construction of Nature
  • ,
  • Scott Atran and Douglas Medin, 2008
  • The Extended Mind
  • ,
  • Richard Menary, editor, 2010
  • Humanity’s End
  • ,
  • Nicholas Agar, 2010
  • Humanity’s End
  • Why We Should Reject Radical Enhancement
  • Nicholas Agar
  • A Bradford Book
  • The MIT Press
  • Cambridge, Massachusetts
  • London, England
  • © 2010
  • 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.
  • For information about special quantity discounts, please email special_sales@
  • This book was set in Stone Sans and Stone Serif by Toppan Best-set Premedia Limited. Printed and bound in the United States of America.
  • Library of Congress Cataloging-in-Publication Data
  • Agar, Nicholas.
  • Humanity’s end : why we should reject radical enhancement / Nicholas Agar.
  •  p. cm.—(Life and mind)
  • "A Bradford book."
  • Includes bibliographical references and index.
  • ISBN 978-0-262-01462-5 (hardcover : alk. paper) 1. Human evolution—Effect of technological innovations on. 2. Technological innovations—Social aspects.  I. Title.
  • GN281.A33 2010
  • 303.48'3—dc22
  • 2010003166
  • 10 9 8 7 6 5 4 3 2
  • Contents
  • Acknowledgments vii
  • 1 What Is Radical Enhancement? 1
  • 2 Radical Enhancement and Posthumanity 17
  • 3 The Technologist—Ray Kurzweil and the Law of Accelerating Returns 35
  • 4 Is Uploading Ourselves into Machines a Good Bet? 57
  • 5 The Therapist—Aubrey de Grey’s Strategies for Engineered Negligible Senescence 83
  • 6 Who Wants to Live Forever? 107
  • 7 The Philosopher—Nick Bostrom on the Morality of Enhancement 133
  • 8 The Sociologist—James Hughes and the Many Paths of Moral Enhancement 151
  • 9 A Species-Relativist Conclusion about Radical Enhancement 179
  • Notes 199
  • Index 217


“Penetrating and lucid…This is the definitive critique of what [Agar] calls ‘radical enhancement.'”—Monash Bioethic Review
“An evenhanded treatment of an area ripe for serious philosophical scrutiny. Agar’s analysis is philosophically astute, empirically informed, and historically shrewd. It is a welcome corrective to the occasional extravagancies of the human sciences.”—Quarterly Review of Biology
“Agar's book is a valuable survey of the most important interlocutors in the conversation about posthumanism...should be taken may well be persuaded by Agar's arguments.”—Journal of Interdisciplinary Studies


“Arguments against radical enhancement have too often in the past been characterized by irrationalism and mysticism. Nicholas Agar presents the first cogent case for the rationality of opposing radical enhancement. Moving easily between science and philosophy, he argues for a species-relative conception of valuable experiences, according to which we have a strong reason to remain human. This central claim is bolstered by a host of other arguments, which will ensure that Humanity’s End will become a central reference point for debates over the desirability of radical enhancement.”
Neil Levy, Oxford Centre for Neuroethics
“Nicholas Agar has written an excellent introduction to the moral challenges of our transition to a posthuman future, engagingly told by contrasting the work of four very different transhumanists. Humanity's End joins Agar's Liberal Eugenics on the must-read list for those interested in the future of the human race.”
James J. Hughes, Executive Director, Institute for Ethics and Emerging Technologies


CHOICE Outstanding Academic Title, 2011