An Essay Concerning Personal Identity
Peter Bennett
Dissertation for the Degree of Master of Philosophy
University of Sussex
November 1992
Peter Bennett An Essay concerning Personal Identity 2
Contents
1 Introduction 10
1 Aim of this thesis: to clear the ground 10
2 First key concept: identity 10
3 Second key concept: person 11
4 Third key concept: punishment 12
5 Preview 13
2 Thought experiments: a prolegomenon to the
philosophy of personal identity 14
1 The problem of thought experimental reasoning 14
TE1: The prince and the cobbler 15
TE2: Exchanging bodies 16
TE3: The callous neurosurgeon 17
2 Why use thought experiments? 18
3 The kind of thought experiments which are used in
the philosophy of personal identity 20
TE4: Travelling at the speed of light 23
4 How to decide whether a thought experiment is
suitable for its purpose 24
TE5: Einstein's clock in a box 25
TE6: Amoebae 29
5 Some examples from Wittgenstein 32
TE7: Look-alike bodies 32
TE8: Jekyll and Hyde 33
3 Locke through the looking-glass 36
1 Locke on identity 36
2 Butler's objection: consciousness presupposes
personal identity 39
TE9: Venetian memories 42
3 Reid's objection: lack of transitivity 44
TE10: The brave officer 44
4 Personal identity as a forensic term 46
Peter Bennett An Essay concerning Personal Identity 3
4 Leibniz and the substantial theory 49
1 Essential and accidental attributes 49
2 Some first principles in Leibniz's philosophy 50
3 Monads and the self 54
4 Leibniz and Locke 55
5 Character and personal identity 62
1 Explanation in terms of character:
Kant and Ryle 62
2 Explanation in terms of character:
Sartre 64
3 Are character explanations satisfactory
explanations? 66
4 How do we make sense of 'a change of
character'? 69
6 Personal identity and punishment 71
1 What is punishment and why is it relevant to
personal identity? 71
2 Punishment as a prima facie mischief 75
3 Utilitarian and non-utilitarian justifications
for punishment 76
4 Deterrence 77
5 Reform 80
6 Prevention 83
7 Penance 83
8 Punishment can be justified entirely within a
utilitarian framework 85
7 Looking back 91
1 A comparison with Parfit 91
2 A review of thought experiments 94
TE11: The robbers 97
3 The ground cleared 97
Appendix:
List of thought experiments 99
Bibliography 105
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Figures
1 Einstein's clock in a box thought experiment
between p. 25 and p. 26
2 Euclid, Book III, Theorem 21
between p. 51 and p. 52
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Acknowledgements
Thanks are due to all my friends and teachers. Of the many
at the University of Sussex who have helped me, particular mention
should go to Andy Clark for his patient supervision of this project
and Magdalena Portmann whose many discussions have done so much
to maintain my enthusiasm for this project. The teachers and
students of the Morley College philosophy class also kept me going
with their lively debates on winter Thursday evenings - thank you. I
should also like to thank Paul Grey who lent me half his library and
disagreed with me about almost everything.
The London Borough of Greenwich and my managers there have
been most flexible and tolerant employers during the second and third
years of this project. During the first year I was supported by a
grant from the British Academy.
I must apologize to my friends and family who I have largely
ignored and neglected during the writing of this thesis.
The illustration for Einstein's clock in a box thought experiment
taken from p. 227 of P. A. Schilpp, Albert Einstein: Philosopher
Scientist appears with the kind permission of the Open Court
Publishing Company.
Peter Bennett An Essay concerning Personal Identity 6
Declaration
I hereby declare that this thesis has not been submitted, either
in the same or different form, to this or any other University for a
degree.
Peter Bennett An Essay concerning Personal Identity 7
Permission to copy
I, Peter James Bennett, author of the thesis An Essay
concerning Personal Identity, give permission to the Librarian of the
University of Sussex to make available for inter-library loan and for
photocopying, the above-mentioned thesis which is deposited in the
University Library. I agree that the abstract of the thesis may be
published in such lists of sources as may be approved from time to
time by the Librarian.
Copyright (c) Peter Bennett 1992
Peter Bennett An Essay concerning Personal Identity 8
Abstract
Working mainly within the Lockean tradition, this thesis clears
some of the ground concerning personal identity. I reject both total
scepticism and an 'anything goes' attitude towards the use of thought
experiments in the philosophy of personal identity and provide
guidelines for assessing the acceptability of a thought experiment. I
argue that too much attention has been paid to the memory theory of
personal identity at the expense of consciousness and concern which
are also mentioned by Locke. This is a mistake both in
interpretation and in current argument. I contrast Locke's ideas with
those of Leibniz and conclude that neither philosopher is sufficiently
explicit about how personal identity relates to punishment and its
justifications. After looking at how character relates to personal
identity I examine the justifications for punishment that can be used
by the utilitarian. I then claim that these justifications are together
sufficient for making sense of the practice of punishment - no non-
utilitarian principles need to be added.
To conclude I contrast my findings with those of Derek Parfit
who in Reasons and Persons considers personal identity in a wider
context than that of punishment. I claim that my conclusions
regarding personal identity are more suitable for his overall
objectives than the ones he provides himself, which show too much
commitment to the memory theory of personal identity. Finally I re-
examine some of the thought experiments considered at the beginning
to show that personal identity is over-analysed. The idea of
concern or expectation is often used as the measuring device in
these thought experiments, which suggests that this is a large part
of what we intuitively think of as personal identity in the first
place.
Peter Bennett An Essay concerning Personal Identity 9
The Commonwealth of Learning, is not at this time without
Master-Builders, whose mighty Designs, in advancing the Sciences, will
leave lasting Monuments to the Admiration of Posterity; But every one
must not hope to be a Boyle, or a Sydenham; and in an Age that
produces such Masters, as the Great - Huygenius, and the
incomparable Mr. Newton, with some other of that Strain; 'tis
Ambition enough to be employed as an Under-Labourer in clearing
Ground a little, and removing some of the Rubbish, that lies in the
way to Knowledge; which certainly had been very much more
advanced in the World, if the Endeavours of ingenious and industrious
Men had not been much cumbred with the learned but frivolous use of
uncouth, affected, or unintelligible Terms, introduced into the
Sciences, and there made an Art of, to that Degree, that Philosophy,
which is nothing but the true Knowledge of Things, was thought unfit,
or uncapable to be brought into well-bred Company, and polite
Conversation. Vague and insignificant Forms of Speech, and Abuse of
Language, have so long passed for Mysteries of Science; And hard or
misapply'd Words, with little or no meaning, have, by Prescription,
such a Right to be mistaken for deep Learning, and heighth of
Speculation, that it will not be easie to persuade, either those who
speak, or those who hear them, that they are but the Covers of
Ignorance, and hindrance of true Knowledge.
[John Locke, 'The Epistle to the Reader' An Essay concerning
Human Understanding; Nidditch pp. 9-10]
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