would discover how imperfect an enumer ration, the logicians have given of the powers of human understanding,, when they reduce them to simple apprehension, judgement, and reasoning.

SECT. 6.On Propositions,

a

Mathematicians use the word proposition in a larger sense than logicians. A problem is called a proposition in mathematics, but in logic it is not a propofition: it is one of those speeches which are not enunciative, and which Aristotle remits to oratory or poetry.

A proposition, according to Aristotle, is a speech wherein one thing is affirmed or denied of another. Hence it is easy to distinguish the thing affirmed or denied, which is called the predicate, from the thing of which it is affirmed or denied, which is called the subject ; and these two are called the terms of the proposition. Hence likewise it appears, that propositions are either affirmative or negative; and this is called their quality. All affirmative propositions have the same quality, so likewise have all negative; but an affirmative and a negative are contrary in their quality.

When the subject of a proposition is a general term, the predicate is affirmed or denied, either of the whole, or of a part. Hence propositions are diftinguished into universal and particular. All men are mortal, is an universal proposition ; Some men are learned, is a particular; and this is called the quantity of the propofition. All universal propositions agree in quantity, as also all particular : but an universal and a particular are said to differ in quantity. A proposition is called indefinite, when there is no mark either of universality or particularity annexed to the subject : thus, Man is of few days, is an indefinite proposition ; but it must be understood either as universal or as particular, and therefore is not a third species, but by interpretation is brought under one of the other two.

There are also fingular propositions, which have not a general terin but an individual for their subject ; as, Alexander was a great conqueror. These are confidered by logicians as universal, because, the subject being indivisible, the predicate

is affirmed or denied of the whole, and not of a part only. Thus alt propositions, with regard to quality, are either affirmative or negative ; and with regard to quantity, are universal or particular; and taking in both quantity and quality, they are universal affirmatives, or universal negatives, or particular affirmatives, or particular negatives. These four kinds, after the days of Aristotle, came to be named by the names of the four first vowels, A, E, I, O, according to the following distich:

ر

Aferit A, negat E, sed universaliter ambæ ;
Aljerit I, negat 0, sed particulariter ambo.

When the young logician is thus far, instructed in the nature of propositions, he is apt to think there is no difficulty in analysing any propofition, and fhewing its subject and predicate, its quantity and quality; and indeed, unless he can do this, he will be unable to apply the rules of logic to use. Yet he will find, there are some difficulties in this analysis, which are overlooked by Aristotle altogether; and although they are sometimes touched, they are not removed by his followers. For, 1. There are propositions in which it is difficult to find a subject and VOL, III,

Xx

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a predicate; as in these, It rains, It frows. 2. In some propositions either term may be made the subject or the predicate as you like best; as in this, Virtue is the road to happiness. 3. The same example: may ferve to fhew, that it is sometimes difficult to say, whether à proposition be universal or particular. 4. The quality of some propositions is so dubious, that logicians, have never been able to agree whether they be affirmative or negative; as in this proposition, Whatever is insentient is not an animal. 5. As there is one class of

propositions which have only two terms, to wit, one subject and one predicate, which are called categorical propositions ; so there are many classes that have more than two terms. What Aristotle delivers in this book is applicable only to categorical propositions, and to them only the rules

; concerning the conversion of propositions, and concerning the figures and modes of fyllogisins, are accommodated. The subsequent writers of logic have taken notice of some of the many classes of complex propositions, and have given rules adapted to them; but finding this work endless, they have left us to manage the rest by the rules of common sense.

CHAP

CHAP.

III.

Account of the First Analytics.

Sect. i. Of the Conversion of Propositions.

IN
N attempting to give some account of

the Analytics and of the Topics of Aristotle, ingenuity requires me to confess, that tho' I have often purposed to read the whole with care, and to underítand what is intelligible, yet iny courage and patience always failed before I had done. Why should I throw away so much time and painful attention upon a thing of so little real use? If I had lived in those ages when the knowledge of Aristotle's Organon intitled a man to the highest rank in philosophy, ambition might have induced me to employ upon it fome years of painful study; and less, I conceive, would not be sufficient. Such reflections as these, always got the better of my resolution, X x 2