Chapter III: Introduction: To Learners

[N.B. Some remarks, addressed to _Teachers_, will be found in the Appendix, at p. 165.]

The Learner, who wishes to try the question _fairly_, whether this little book does, or does not, supply the materials for a most interesting mental recreation, is _earnestly_ advised to adopt the following Rules:--

(1) Begin at the _beginning_, and do not allow yourself to gratify a mere idle curiosity by dipping into the book, here and there. This would very likely lead to your throwing it aside, with the remark "This is _much_ too hard for me!", and thus losing the chance of adding a very _large_ item to your stock of mental delights. This Rule (of not _dipping_) is very _desirable_ with _other_ kinds of books----such as novels, for instance, where you may easily spoil much of the enjoyment you would otherwise get from the story, by dipping into it further on, so that what the author meant to be a pleasant surprise comes to you as a matter of course. Some people, I know, make a practice of looking into Vol. III first, just to see how the story ends: and perhaps it _is_ as well just to know that all ends _happily_----that the much-persecuted lovers _do_ marry after all, that he is proved to be quite innocent of the murder, that the wicked cousin is completely foiled in his plot and gets the punishment he deserves, and that the rich uncle in India (_Qu._ Why in _India_? _Ans._ Because, somehow, uncles never _can_ get rich anywhere else) dies at exactly the right moment----before taking the trouble to read Vol. I. This, I say, is _just_ permissible with a _novel_, where Vol. III has a _meaning_, even for those who have not read the earlier part of the story; but, with a _scientific_ book, it is sheer insanity: you will find the latter part _hopelessly_ unintelligible, if you read it before reaching it in regular course. pg-xii (2) Don't begin any fresh Chapter, or Section, until you are certain that you _thoroughly_ understand the whole book _up to that point_, and that you have worked, correctly, most if not all of the examples which have been set. So long as you are conscious that all the land you have passed through is absolutely _conquered_, and that you are leaving no unsolved difficulties _behind_ you, which will be sure to turn up again later on, your triumphal progress will be easy and delightful. Otherwise, you will find your state of puzzlement get worse and worse as you proceed, till you give up the whole thing in utter disgust.

(3) When you come to any passage you don't understand, _read it again_: if you _still_ don't understand it, _read it again_: if you fail, even after _three_ readings, very likely your brain is getting a little tired. In that case, put the book away, and take to other occupations, and next day, when you come to it fresh, you will very likely find that it is _quite_ easy.

(4) If possible, find some genial friend, who will read the book along with you, and will talk over the difficulties with you. _Talking_ is a wonderful smoother-over of difficulties. When _I_ come upon anything----in Logic or in any other hard subject----that entirely puzzles me, I find it a capital plan to talk it over, _aloud_, even when I am all alone. One can explain things so _clearly_ to one's self! And then, you know, one is so _patient_ with one's self: one _never_ gets irritated at one's own stupidity!

If, dear Reader, you will faithfully observe these Rules, and so give my little book a really _fair_ trial, I promise you, most confidently, that you will find Symbolic Logic to be one of the most, if not _the_ most, fascinating of mental recreations! In this First Part, I have carefully avoided all difficulties which seemed to me to be beyond the grasp of an intelligent child of (say) twelve or fourteen years of age. I have myself taught most of its contents, _vivâ voce_, to _many_ children, and have found them take a real intelligent interest in the subject. For those, who succeed in mastering Part I, and who begin, like Oliver, "asking for more," I hope to provide, in Part II, some _tolerably_ hard nuts to crack----nuts that will require all the nut-crackers they happen to possess! pg-xiii Mental recreation is a thing that we all of us need for our mental health; and you may get much healthy enjoyment, no doubt, from Games, such as Back-gammon, Chess, and the new Game "Halma". But, after all, when you have made yourself a first-rate player at any one of these Games, you have nothing real to _show_ for it, as a _result!_ You enjoyed the Game, and the victory, no doubt, _at the time_: but you have no _result_ that you can treasure up and get real _good_ out of. And, all the while, you have been leaving unexplored a perfect _mine_ of wealth. Once master the machinery of Symbolic Logic, and you have a mental occupation always at hand, of absorbing interest, and one that will be of real _use_ to you in _any_ subject you may take up. It will give you clearness of thought----the ability to _see your way_ through a puzzle----the habit of arranging your ideas in an orderly and get-at-able form----and, more valuable than all, the power to detect _fallacies_, and to tear to pieces the flimsy illogical arguments, which you will so continually encounter in books, in newspapers, in speeches, and even in sermons, and which so easily delude those who have never taken the trouble to master this fascinating Art. _Try it._ That is all I ask of you!

L. C.

29, BEDFORD STREET, STRAND.
_February 21, 1896._

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CONTENTS.

=BOOK I.=

=THINGS AND THEIR ATTRIBUTES.=

CHAPTER I.

_INTRODUCTORY._

PAGE
'=Things=' 1

'=Attributes=' "

'=Adjuncts=' "

CHAPTER II.

_CLASSIFICATION._

'=Classification=' 1½

'=Class=' "

'=Peculiar=' Attributes "

'=Genus=' "

'=Species=' "

'=Differentia=' "

'=Real=' and '=Unreal=', or '=Imaginary=', Classes 2

'=Individual=' "

A Class regarded as a single Thing 2½

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CHAPTER III.

_DIVISION._

§ 1.

_Introductory._

'=Division=' 3

'=Codivisional=' Classes "

§ 2.

_Dichotomy._

'=Dichotomy=' 3½

Arbitrary limits of Classes "

Subdivision of Classes 4

CHAPTER IV.

_NAMES._

'=Name=' 4½

'=Real=' and '=Unreal=' Names "

Three ways of expressing a Name "

Two senses in which a plural Name may be used 5

CHAPTER V.

_DEFINITIONS._

'=Definition=' 6

Examples worked as models "

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=BOOK II.=

=PROPOSITIONS.=