position, of which both terms are single propositions, and which differs from the hypothesis by the assertion it contains of the truth of these elementary propositions; that is, of the truth of the existence of the terms which they constitute. When we say, "Cæsar was a tyrant, therefore he deserved death," one of these propositions does not follow from the other, and therefore it is no argument, but merely a compound proposition.

But if we suppose a tyrant to have been defined "a person deserving death," which is the same as if we suppose there to be another premiss, "All tyrants deserve death,” thus reduced, "Every tyrant is a person deserving death," the enthymeme becomes a syllogism of which this premiss is understood.

The use of these distinctions is to avoid a very frequent fallacy arising from the use of the enthymeme. By this form an appearance of argumentation is often given to a single assertion; the conclusion may appear to be the result of the expressed premiss, the truth of which may be incontrovertible; but when you come to examine what must be the understood premiss, in order to form such a conclusion, you will often find that

it is one of which the truth is very doubtful, not to say absolutely impossible.

The sorites (Elements, p.122) might be easily reduced to a regular series of syllogisms, were there any use in the operation. The enthymematic sentence (p. 124) is one in which a pronoun is used for a noun; at least in the author's example; for I cannot conceive that, in the proposition, "All useful studies deserve encouragement, Logic is such," such is any thing but a pronoun referring to useful studies; nor can I conceive that any such proposition as "since it helps us to reason accurately" is implied or understood. Induction (Elements, p.123) forms the subjectmatter of my next chapter.

The syllogisms apparently incorrect, which conclude this section of the Elements, relate only to the "Barbara" system. If a syllogism has been defined an "argument of which the validity is evident from the mere force of the terms," it is difficult to conceive a syllogism apparently incorrect.

In concluding the present chapter, Dr. Whately reverts once more to the great extension of the field of Logic, of which he accuses logicians in general; a topic which has been too often discussed to be again entered into at present. His

mention of it is on the occasion of introducing the chapter on Fallacies: an important one in the ratiocinative part of Logic. But this is a subject of which I must defer the consideration till after having treated of Induction; as fallacy in argument applies to the inductive as well as to the deductive operation.

172

CHAPTER X.

INDUCTION.

(Whately's Elements, Province of Reasoning, Ch. I. Induction, p. 207.)

THE next mental operation, which, according to the general view I have taken of the field of this science, comes under the head of Logic, is that of Induction, which may be thus characterized: “From the existence of a fact, or from the occurrence of a phenomenon, certain or probable, in any one case or in several similar cases, the inferring that a similar fact or phenomenon has place in some other analogous case." Whatsoever general rules can be given, as to the degree of probability of the data or premises, as well as to that of the conclusion or fact inferred,—such rules form the subject-matter of the theory of induction.

This operation is, by Dr. Whately, excluded from the province of Logic, and only treated of

incidentally, in his Elements, as a subject connected with Logic. He therefore has not thought it necessary to give a regular definition of the word induction; but the meaning he attaches to it (when different in sense from deduction or syllogistic ratiocination) may be gathered from the following passage:

"Whether the induction (in this last sense*) has been sufficiently ample, i. e. takes in a sufficient number of individual cases,-whether the charac'ter of those cases has been correctly ascertained—

and how far the individuals we have examined are likely to resemble, in this or that circumstance, the rest of the class, &c. &c., are points that require indeed great judgment and caution; but this judgment and caution are not to be aided by Logic, because they are, in reality, employed in deciding whether or not it is fair and allowable to lay down your premises; i. e. whether you are authorised or not, to assert, that what is true of the individuals you have examined, is true of the whole class, and that this or that is true of those individuals." p. 210.

* That is, when it cannot be stated syllogistically.