that the last is necessarily inferred from the two which precede it.

In the composition of a syllogism two things are to be considered, viz. its matter and its form. The matter consists of three propositions composed of three ideas or terms variously joined. These three terms are called the major, the minor, and the middle. The predicate of the conclusion is called the major term, because it is commonly of a larger compass and more general signification than the minor term, or subject of the conclusion, The major and minor terms are called the extremes. The middle term is the third 'idea disposed in two propositions, in such a manner as to show the connexion between the major and minor terms in the conclusion, for which reason the middle term itself is sometimes called the argument. The proposition, which contains the predicate of the conclusion connected with the middle term, is usually called the major proposition; whereas the minor proposition connects the middle term with the subject of the conclusion, and is sometimes called the assumption. These rules are chiefly applicable to simple or categorical syllogisms, although every syllogism contains something analogous to them*.

Compound syllogisms are composed of two or more single ones, and may be resolved into them: the chief kinds are the epichirema, the dilemma, and the sorites. These figures are liable to abuse, and are often more specious than solid. The epichirema is an argument, which contains the proof of the major and the minor or both, before it draws the conclusion. This is frequently used in writing, in public speeches, and in common conversation, in order that each part of the * Watt's Logic, p. 281, 301, &c.

discourse may be confirmed, and put out of doubt, as it proceeds towards the conclusion, which was chiefly designed. Thus the oration of Cicero, for Milo, may be reduced to this figure. "It is lawful for a person to kill those who lie in wait to kill him, as is allowed by the law of nature, and the practice of mankind. But Clodius lay in wait for Milo with that intention, as appears from his guard of soldiers and his travelling armed; therefore it was lawful for Milo to kill Clodius." The dilemma divides the whole argument into all its parts or members by a disjunctive proposition, and then infers something concerning each part, which is finally inferred concerning the whole. Thus Cicero argues to prove, that all pain ought to be borne with patience. "All pain is either violent or slight; if it be slight, it may easily be endured; if violent, it will certainly be short; therefore all pain ought to be borne with patience." But for this figure to be correct two things are required, 1. the full enumeration of all the particulars of a subject; 2. that it press the opponent only, and not be liable to be retorted upon the person who uses it. In the sorites several middle terms are used to connect one another successively in several propositions, till the last proposition connects its predicate with the first subject. Such is the jocular argument of Themistocles to prove that his little son governed the whole world. My son governs his mother, his mother governs me; I govern the Athenians, the Athenians all Greece; Greece commands Europe, and Europe the world."

There is one kind of syllogism which is defective, and is called an enthymem, because only the concluclusion with one of the premises is expressed, whilst the other is reserved in the mind. This forms the

most common kind of argument, both in conversation and in writing; for it would require too much time to draw out all our thoughts in regular order, according to mood and figure. Besides, we pay so much respect to the understanding of others, as to suppose that they are acquainted with the major or minor, which is suppressed or implied, when we state the other premises, and the conclusion.

With respect to the nature of sophistry or false reasoning, and the best methods of detecting its various artifices to impose upon the understanding, the popular treaties upon this subject, particularly Logic, or the right use of Reason, by Watts, and the Conduct of the Understanding, by Locke, may be consulted to great advantage.

*

From the short survey we have taken, it appears, that logic, beginning with the first principles of thought, ascends gradually from one decision of the judgment to another, and connects these decisions in such a manner, that every stage of the progression brings intuitive certainty with it. It appears likewise that reason is the ability of deducing unknown truths from propositions that are already known; and that no proposition is admitted into a syllogism, as one of the previous judgments upon which the conclusion rests, unless it is itself a known and established truth, and the connexion of which with selfevident principles has been already traced.

If Aristotle was not the first, who reduced logic to a system, he was certainly the most eminent of logicians.† He claims the invention of the whole theory

* See particularly Section 42.

For a very clear account of Aristotle and his works, see his Ethics and Politics by Dr. Gillies, 2 vol. 4to. 1797.

of syllogisms. He analysed them with astonishing subtlety, exhibited them to view in every shape, enacted the laws by which they are regulated, and invented all the forms into which they can be moulded. All subsequent writers upon the subject of dialectics have been indebted to him for nearly the whole of their systems. But after mankind had involved themselves in the labyrinths of Aristotelian disputation for near two thousand years, and perplexed their understandings to little purpose, the great lord Bacon proposed the method of induction, as a more effectual means of arriving at truth.*

By Induction is meant a general inference drawn from several particular propositions. This method has contributed very materially to the improvement of the arts, and the increase of knowledge, more particularly in the researches of natural philosophy. Upon the use of induction as applied to the general discovery of truth, the ingenious author of " The Chart and Scale of Truth" makes this excellent remark. "As induction is the first, so it is the most essential and fundamental instrument of reasoning: for as syllogism can never produce its own principles, it must have them from induction; and, if the general propositions, or secondary principles, be imperfectly or infirmly established, and much more if they be taken at hazard, upon authority, or by arbitrary assumption, like those of Aristotle, all the syllogising in the world is a vain and useless logomachy, only instrumental to the multiplication of false learning, and to the invention and confirmation of error. The truth of syllogisms de

* Lord Bacon's general plan will be fully explained in the following chapter.

pends ultimately on the truth of axioms, and the truth of axioms on the soundness of inductions* "

IV. The fourth operation of the mind relates to the arrangement of our thoughts, when we endeavour to unite them in such a manner, that their mutual connexion and dependence may be clearly seen. To this operation the logicians give the name of METHOD; and in the course of their development of the powers of the understanding, they assign to it the last place.

In the arrangement of our thoughts, either for our own use, or when we intend to communicate and unfold our discoveries to others, there are two modes of proceeding, which are equally in our power to choose : for we may so propose the truths relating to any sub ject of inquiry or part of knowledge, as they presented themselves to the mind, and carry on the series of proofs in a reverse order, until they at last terminate in first principles: or, beginning with these principles, we may adopt the contrary method, and from them deduce, by a direct train of reasoning, all the propositions we desire to establish. From this diversity in the manner of arranging our thoughts originates the two fold division of method. When truths are so proposed, and put together as they were, or might have been discovered, this is called the analytic method, or the method of resolution; inasmuch as it traces things

* Chart and Scale of Truth, vol. i, p. 50. Syllogismus ex propositionibus constat, propositiones ex verbis, verba notionum tessera sunt. Itaque si notiones ipsa (id quod basis rei est) confusæ sint & temere a rebus abstracta, nihil in iis quæ superstruuntur est firmitudinis. Itaque spes est una in inductione vera. Baconi Novum Organ: vol. i, p. 275.