Logic Matters

344 Pages·11.984 MB·English

by  Peter T. Geach

Logic Matters
p. T. GEACH
UNIVERSITY OF CALIFORNIA PRESS
Berkeley and Los Angeles 1972
UNIVERSITY OF CALIFORNIA PRESS
Berkeley and Los Angeles, California
ISBN: 0-520-01851-6
Library of Congress Catalog Card Number: 72-138286
© Basil Blackwell 1972
All Rights Reserved. No part of this publication may be repro¬
duced, stored in a retrieval system, or transmitted, in any form
or by any means, electronic, mechanical, photocopying, recording
or otherwise, without the prior permission of the University
of California Press.
Printed in Great Britain
Ku c%ci tych co polegli w sprawie Ojczy^ny
\
Preface
I here bring together almost all my English articles that I have
previously published and have not already collected or cannibal¬
ized in other books. They are arranged not chronologically but
topically under various headings, in as good an order as I could
devise. I have made many stylistic changes, removed incidental
errors, and deleted inessential adverse criticisms of other authors.
However, nearly all the articles appear without substantial change.
I have added a very few brief afterthoughts in footnotes, under the
rubric ‘(Note, 1969)’.
Only one article has undergone more drastic surgery: ‘Quanti¬
fication theory and the problem of identifying objects of refer¬
ence’. In this one article I rashly put over two unconventional
theories: a theory of quantification, inspired by Lesniewski and
previously sketched in my book Reference and Generality', and a
theory of quotation, inspired by K. Reach. The first theory was
used in expounding the second, but did not commit me to the
second; I was and am much more certain that the first theory is
sound than that the second is, and I have much regretted that I
prejudiced the first theory’s chances of winning acceptance by
this way of presenting it. In reprinting the article I have accord¬
ingly excised the pages that dealt with quoted occurrences of
expressions; these now appear with slight rewriting as a separate
article ‘Quotation and quantification’.
In the final section of the book, ‘Logic in Metaphysics and
Theology’, the article ‘Nominalism’ was originally addressed to
an audience of Catholic priests: I was urging that the crude logic
Vlll PREFACE
of the ordinary Scholastic manuals is positively harmful to
theological thinking. This article was included because it may
possibly interest readers who do not share the author’s faith; I
must ask such readers’ indulgence for my not questioning, but
simply assuming, certain highly controversial positions; before
my original audience I did not need to argue the truth of these
positions, but was concerned to draw out their consequences as I
saw them.
My first published article ‘Designation and truth’, which now
stands in section 5, originally bore a Polish dedication; this now
appears as a motto for the book. I dedicate this book to the
glorious memory of those who died for Poland’s freedom,
honour, and civilised existence. To those who worked at peril of
their lives in Poland’s underground Universities, logic and all
learning mattered indeed. Life, we are often told, is more than
logic; but for these Poles logic was more than life. The survivors
of those gallant men and women teach in the Polish Universities
today, and the torch is handed on.
P. T. Geach
University of Leeds
Michaelmas 1969
Contents
Preface vii
Acknowledgements xi
1. Historical Essays 1
1.1. History of a fallacy 1
1.2. Aristotle on conjunctive propositions 13
1.3. Russell on meaning and denoting 27
1.4. Plato’s Euthyphro 31
1.5. History of the corruptions of logic 44
2. Traditional Logic 62
2.1. Distribution: a last word ? 62
2.2. Toms on distribution 65
2.3. Strawson on symbolic and traditional logic 66
2.4. Contradictories and contraries 70
2.5. The law of excluded middle 74
3. Theory of Reference and Syntax 88
3.1. Ryle on namely-riders 88
3.2. Namely-riders again 92
3.3. What are referring expressions ? 95
3.4. Referring expressions again 97
3.5. On complex terms 102
3.6. Complex terms again 106
3.7. Logical procedures and the identity of expressions 108
3.8. Quine’s syntactical insights 115
4. Intentionality 128
4.1. On beliefs about oneself 128
4.2. A medieval discussion of intentionality 129
X CONTENTS
4.3. Quantification theory and the problem of identifying
objects of reference 139
4.4. Intentional identity 146
4.5. The perils of Pauline 153
4.6. The identity of Propositions 166
4.7. Entailment 174
4.8. Entailment again 186
5. Quotation and Semantics 189
5.1. Designation and truth 189
5.2. Designation and truth—a reply 193
5.3. 7/s and ands 194
5.4. On rigour in semantics 198
5.5. ‘Necessary propositions and entailment statements’ 201
5.6. On names of expressions 203
5.7. Is it right to say or is a conjunction? 204
5.8. Quotation and quantification 205
5.9. On insolubilia 209
6. Set Theory 212
6.1. Frege’s Grundlagen 212
6.2. Quine on classes and properties 222
6.3. Class and concept 226
6.4. On Frege’s way out 235
7. Identity Theory 238
7.1. Identity 238
7.2. Identity—a reply 247
8. Assertion 250
8.1. Ascriptivism 250
8.2. Assertion 254
9. Imperatives and Practical Reasoning 270
9.1. Imperative and deontic logic 270
9.2. Imperative inference 278
9.3. Kenny on practical reasoning 285
10. Logic in Metaphysics and Theology 289
10.1. Nominalism 289
10.2. Some problems about time 302
10.3. God’s relation to the world 318
Acknowledgements
The articles in this volume originally appeared in the following
periodicals and collections. The editors and publishers are grate¬
fully thanked for permission to reprint.
1.1 Journal of the Philosophical Association (Bombay), vol.
5, no. 19-20, 1958
1.2 Ratio, vol. 5, no. 1, 1963
1.3 Analysis, vol. 19, no. 3, 1958-59
1.4 The Monist, vol. 50, no. 3, 1966
1.5 An inaugural lecture delivered at the University of Leeds,
22 January, 1968: printed as a pamphlet, Leeds University Press,
1968, and reprinted in the University of Leeds Review, vol. 12,
no. 1, 1969. This is a longer version of a Polish article Nazwy i
Orzeczniki, which has since been published in Semiotyka Polska;
Panstwowe Wydawnictwo Naukowe, Warsaw 1972
2.1 Philosophical Review, vol. 69, no. 3, 1960
2.2 Mind, vol. 77, no. 1, 1968
2.3 Mind, vol. 72, no. 1, 1963
2.4 Analysis, vol. 29, no. 6, 1969-70
2.5 Aristotelian Society Supplementary Volume 30, 1956
3.1 Analysis, vol. 21, no. 3, 1960-61
3.2 Analysis, vol. 22, no. 4, 1961-62
3.3 Analysis, vol. 23, no. 1, 1962-63
3.4 Analysis vol. 24, no. 5, 1963-64
3.5 Journal of Philosophy, vol. 72, no. 1, 1965
3.6 Journal of Philosophy, vol. 72, no. 23, 1965
3.7 Ratio, vol. 7, no. 2, 1965
XU ACKNOWLEDGEMENTS
3.8 Synthese, vol. 19, no. 1/2, 1968-69
4.1 Analysis, vol. 18, no. 1, 1957-58
4.2 Proceedings of the International Congress for Logic,
Methodology, and Philosophy of Science, Jerusalem, 1964
4.3 Acta Philosophica Fennica, fasc. 16, 1963
4.4 Journal of Philosophy, vol. 74, no. 20, 1967
4.5 Review of Metaphysics, vol. 23, no. 2
4.6 Ksiega Pamiatkowa ku czci T. Kotarbinskiego (Frag-
menty Filozoficzne, Seria Trzecia): Panstwowe Wydawnictwo
Naukowe, Warsaw, 1967
4.7 Aristotelian Society Supplementary Volume 32, 1958
4.8 Philosophical Review, vol. 79, no. 2, 1970
5.1 Analysis, vol. 8, no. 6, 1947M8
5.2 Analysis, vol. 10, no. 5, 1949-50
5.3 Analysis, vol. 9, no. 3, 1948-49
5.4 Mind, vol. 58, no. 4, 1949
5.5 Mind, vol. 57, no. 4, 1948
5.6 Mind, vol. 59, no. 4, 1950
5.7 Analysis, vol. 19, no. 6, 1958-59
5.8 (Originally part of 4.3; see Preface)
5.9 Analysis, vol. 15, no. 2, 1954—55
6.1 Philosophical Review, vol. 60, no. 4, 1951
6.2 Philosophical Review, vol. 62, no. 4, 1953
6.3 Philosophical Review, vol. 64, no. 4, 1955
6.4 Mind, vol. 65, no. 3, 1956
7.1 Review of Metaphysics, vol. 21, no. 1, 1967
7.2 Review of Metaphysics, vol. 22, no. 3, 1969
8.1 Philosophical Review, vol. 69, no. 2, 1960
8.2 Philosophical Review, vol. 74, no. 4, 1965
9.1 Analysis, vol. 18, no. 3, 1957-8
9.2 Analysis, supplement to vol. 23, 1963
9.3 Analysis, vol. 26, no. 3, 1965-6
10.1 Sophia, vol. 3, no. 2, 1964
10.2 Proceedings of the British Academy, 1965
10.3 Sophia, vol. 8, no. 2, 1969.
1
Historical Essays
1.1. HISTORY OF A FALLACY
The logical fallacy that I am going to discuss here is one that
it is quite easy to see by common sense in simple examples. For
all that, it is of great philosophical importance. Anybody can see
that from “Every boy loves some girl” we cannot infer “There is
some girl that every boy loves”; that from “It is obligatory that
somebody should go” it does not follow that “There is somebody
who it is obligatory should go”, for the obligation that somebody
should go may be fulfilled by somebody’s volunteering to go when
he was not obliged; that there is a natural way of taking “Every
one of these books it is possible to read in less than half an hour”
and on the other hand “It is possible to read every one of these
books in less than half an hour” so that the latter does not follow
from the former. In the light of modern logic one might call this
the operator-shift or quantifier-shift fallacy, because the difference
between the premise and the conclusion fallaciously inferred from
it would be symbolized by a difference in relative position between
two operators—an existential and a universal quantifier, or a
quantifier and a modal operator like “it is obligatory” or “it is
possible”. But the application of formal logic to statements made
in the vernacular has lately been rather blown upon; and I must
therefore not assume at the outset that this is the correct descrip¬
tion of the fallacy, by calling it the operator-shift fallacy. I shall
for the moment christen it the boy-and-girl fallacy, after my first
example of it.