connects the middle term with the fubject of the conclufion, and is fometimes called the affumption. These rules are chiefly applicable to fimple or categorical fyllogifms, although every fyllogifm contains fomething analogous to them'.

Compound fyllogifms are compofed of two or more fingle ones, and may be refolved into them: the chief kinds are the Epichirema, the Dilemma, and the Sorites. These figures are liable to abuse, and are often more fpecious than folid. The epichirema is an argument, which contains the proof of the major and the minor, or both, before it draws the conclufion. This is frequently ufed in writing, in public fpeeches, and in common converfation, in order that each part of the discourse may be confirmed, and put out of doubt, as it proceeds towards the conclufion, which was chiefly defigned. Thus the oration of Cicero, for Milo, may be reduced to this figure. "It is lawful for a perfon 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 laid in wait for Milo with that intention, as appears from his guard of foldiers 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 propofition, and then infers fomething concerning each part, which is finally inferred concerrning the whole. Thus Cicero argues to

VOL. II.

i Watts's Logic, p. 281, 301, &c.

F

prove,

prove, that all pain ought to be borne with patience. All pain is either violent or flight; if it be flight, it may easily be endured; if violent, it will certainly be fhort; 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 prefs the opponent only, and not be liable to be retorted upon the perfon who ufes it. In the forites feveral middle terms are used to connect one another fucceffively in feveral propofitions, till the last propofition connects its predicate with the first fubject. Such is the jocular argument of Themiftocles to prove that his little fon governed the whole world. 'My fon 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 fyllogifm which is defective, and is called an Enthymem, because only the conclufion with one of the premises is expreffed, whilft the other is reserved in the mind. This forms the most common kind of argument, both in converfation and in writing; for it would require too much time to draw out all our thoughts in regular order, according to mood and figure. Befides, we pay fo much refpect to the understanding of others, as to fuppofe that they are acquainted with the major or minor, which is fuppreffed or implied, when we ftate the other premifes, and the conclufion.

With refpect to the nature of fophiftry, or falfe reafoning, and the best methods of detecting its various artifices to impofe upon the understanding, the popular treatises upon this fubject, particularly Logic, or the right use of Reason, by Watts, and the Conduct of the Understanding, by Locke*, may be confulted to great advantage.

From the short furvey we have taken, it appears, that Logic, beginning with the first principles of thought, afcends gradually from one decifion of the judgment to another, and connects thefe decifions in fuch a manner, that every ftage of the progreffion brings intuitive certainty with it. It appears likewise that reafon is the ability of deducing unknown truths from propositions that are already known; and that no propofition is admitted into a fyllogifm, as one of the previous judgments upon which the conclufion refts, unless it is itself a known and established truth, and the connexion of which with self-evident principles has been already traced.

If Aristotle was not the firft, who reduced Logic to a system, he was certainly the moft eminent of logicians'. He claims the invention of the whole theory of fyllogifms. He analyfed them with aftonishing fubtlety, exhibited them to view in

k See particularly Section 42.

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

every shape, enacted the laws, by which they are regulated, and invented all the forms, into which they can be moulded. All fubfequent writers upon the fubject of dialectics have been indebted to him for nearly the whole of their fyftems. But after mankind had involved themselves in the labyrinths of Ariftotelian difputation for near two thoufand 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 truthm.

By Induction is meant a general inference drawn from feveral particular propofitions. This method has contributed very materially to the improvement of the arts, and the increase of knowledge, more particularly in the researches of natural philofophy. 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 firft, fo it is the more effential and fundamental inftrument of reafoning for as fyllogifm can never produce its own principles, it must have them from induction; and, if the general propofitions, or fecondary principles, be imperfectly or infirmly established, and much more if they be taken at hazard, upon authority, or by arbitrary affumption, like thofe of Ariftotle,

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

all

all the fyllogifing in the world is a vain and ufelefs logomachy, only inftrumental to the multiplication of falfe learning, and to the invention and confirmation of error. The truth of fyllogifms depends ultimately on the truth of axioms, and the fruth of axioms on the foundness of inductions".

IV. The fourth operation of the mind relates to the arrangement of our thoughts, when we endeavour to unite them in fuch a manner, that their mutual connexion and dependance may be clearly feen. To this operation the logicians give the name of METHOD; and in the courfe of their developement of the powers of the understanding, they affign to it the last place.

In the arrangement of our thoughts, either for our own ufe, or when we intend to communicate and unfold our difcoveries to others, there are two modes of proceeding, which are equally in our power to choofe: for we may fo propose the truths relating to any fubject of inquiry or part of knowledge, as they prefented themfelves to the mind, and carry on the feries of proofs in a reverse order, until they at laft terminate in firft principles: or,

n Chart and Scale of Truth, vol. i. p. 50. Syllogifmus ex propofitionibus conftat, propofitiones ex verbis, verba notionum. tefferæ funt. Itaque fi notiones ipfæ (id quod bafis rei eft) confufæ fint & temere a rebus abstractæ, nihil in iis quæ fuperftruuntur eft firmitudinis. Itaque fpes eft una in inductione vera. Baconi Novum Organ: vol. i. p. 275.