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                                                                   pg-i

SYMBOLIC LOGIC

By Lewis Carroll
                                                                   pg-ii
                                                                   pg-iii
                                                                   pg-iv

A Syllogism worked out.

That story of yours, about your once meeting the sea-serpent, always
sets me off yawning;

I never yawn, unless when I'm listening to something totally devoid of
interest.

The Premisses, separately.

   .---------------.          .---------------.
    |( )    |    ( )|           |       |       |
    |  .---|---.   |           |  .---|---.   |
    |   |  (#)  |   |           |   |   |( )|   |
    |---|---|---|---|           |---|---|---|---|
    |   |   |   |   |           |   |   |( )|   |
    |  .---|---.   |           |  .---|---.   |
    |       |       |           |       |       |
   .---------------.          .---------------.

The Premisses, combined.

   .---------------.
    |( )    |    ( )|
    |  .---|---.   |
    |   |(#)|( )|   |
    |---|---|---|---|
    |   |   |( )|   |
    |  .---|---.   |
    |       |       |
   .---------------.

The Conclusion.

   .-------.
    |(#)|( )|
    |---|---|
    |   |   |
   .-------.

That story of yours, about your once meeting the sea-serpent, is totally
devoid of interest.

                                                                   pg-v


                           SYMBOLIC LOGIC


                              _PART I_

                             ELEMENTARY



                                 BY

                            LEWIS CARROLL


                           SECOND THOUSAND

                           FOURTH EDITION


                        _PRICE TWO SHILLINGS_


                               London
                     MACMILLAN AND CO., LIMITED
                   NEW YORK: THE MACMILLAN COMPANY
                                1897

                        _All rights reserved_


                                                                   pg-vi

                   RICHARD CLAY AND SONS, LIMITED,
                          LONDON AND BUNGAY

                                                                   pg-vii


ADVERTISEMENT.


An envelope, containing two blank Diagrams (Biliteral and Triliteral)
and 9 counters (4 Red and 5 Grey), may be had, from Messrs. Macmillan,
for 3_d._, by post 4_d._

       *       *       *       *       *

I shall be grateful to any Reader of this book who will point out any
mistakes or misprints he may happen to notice in it, or any passage
which he thinks is not clearly expressed.

       *       *       *       *       *

I have a quantity of MS. in hand for Parts II and III, and hope to be
able----should life, and health, and opportunity, be granted to me, to
publish them in the course of the next few years. Their contents will be
as follows:--

_PART II. ADVANCED._

Further investigations in the subjects of Part I. Propositions of other
forms (such as "Not-all x are y"). Triliteral and Multiliteral
Propositions (such as "All abc are de"). Hypotheticals. Dilemmas. &c.
&c.

_Part III. TRANSCENDENTAL._

Analysis of a Proposition into its Elements. Numerical and Geometrical
Problems. The Theory of Inference. The Construction of Problems. And
many other _Curiosa Logica_.

                                                                   pg-viii


PREFACE TO THE FOURTH EDITION.


The chief alterations, since the First Edition, have been made in the
Chapter on 'Classification' (pp. 2, 3) and the Book on 'Propositions'
(pp. 10 to 19). The chief additions have been the questions on words and
phrases, added to the Examination-Papers at p. 94, and the Notes
inserted at pp. 164, 194.

In Book I, Chapter II, I have adopted a new definition of
'Classification', which enables me to regard the whole Universe as a
'Class,' and thus to dispense with the very awkward phrase 'a Set of
Things.'

In the Chapter on 'Propositions of Existence' I have adopted a new
'normal form,' in which the Class, whose existence is affirmed or
denied, is regarded as the _Predicate_, instead of the _Subject_, of the
Proposition, thus evading a very subtle difficulty which besets the
other form. These subtle difficulties seem to lie at the root of every
Tree of Knowledge, and they are _far_ more hopeless to grapple with than
any that occur in its higher branches. For example, the difficulties of
the Forty-Seventh Proposition of Euclid are mere child's play compared
with the mental torture endured in the effort to think out the essential
nature of a straight Line. And, in the present work