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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 distinguished 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 proposition. 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, lan 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 term 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
Aljerit A, negat E, fed univerfaliter ambæ ;
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 shewing 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 fome 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 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.
The same example may serve to shew, that it is sometimes difficult to say, whether a proposition be universal or particular. 4. The quality of some propofitions is so dubious, that logicians have never been able to agree whether they be affirmative or negative.; as in this proposition, Whatever is infentient 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
clafles 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 fyllogisms, 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 mathe rest by the rules of common sense.
the Analytics and of the Topics of Aristotle, ingenuity requires me to confess, that though I have often purposed to read the whole with care, and to understand what is intelligible, yet my courage and patience always failed before I had done. Why should I throw away so much time and painful attention upon a thing of fo 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 some years of painful study; and less, I conceive, would not be sufficient. Such reflections as these, always got the better of my resolution,
when the first ardor began to cool. All I can say is, that I have read some parts of the different books with care, fome flightly, and some perhaps not at all. I have glanced over the whole often, and when any thing attracted my attention, have dipped into it till my appetite was satisfied. Of all reading it is the most dry and the moit painful, employing an infinite labour of demonstration, about things of the most abstract nature, delivered in a laconic style, and often, I think, with affected obfcurity; and all to prove general propositions, which when applied to particular in tances appear felf-evident.
There is probably but little in the Categories or in the book of Interpretation, that Aristotle could claim as his own invention : but the whole theory of fyllogisms he claims as his own, and as the fruit of much time and labour. And indeed it is a stately fabric, a monument of a great genius, which we could wish to have been more usefully employed. There must be fornething however adapted to please the human understanding, or to flatter human pride, in a work which occupied men of speculation for more than a thousand