a right understanding of the powers of our own minds, by which fuch notions are formed.

The principles laid down by Locke with regard to definition, and with regard to the abufe of words, carry conviction along with them. I take them to be one of the most important improvements made in logic fince the days of Ariftotle: not so much becaufe they enlarge our knowledge, as because they make us fenfible of our ignorance; and fhew that a great part of what, fpeculative men have admired as profound philofophy, is only a darkening of knowledge by words without understanding.

If Ariftotle had understood these principles, many of his definitions, which furnish matter of triumph to his enemies, had never feen the light: let us impute them to the times rather than to the man. The fublime Plato, it is faid, thought it neceffary to have the definition of a man, and could find none better than Animal implume bipes; upon' which Diogenes fent to his fchool a cock with his feathers plucked off, defiring to know whether it

was a man or not.

SECT. 5. On the Structure of Speech.

The few hints contained in the beginning of the book concerning Interpretation relating to the ftructure of fpeech, have been left out in treatises of logic, as belonging rather to grammar; yet I VOL. III. apprehend

C

apprehend this is a rich field of philofophical speculation. Language being the exprefs image of human thought, the analysis of the one must correspond to that of the other. Nouns adjective and fubftantive, verbs active and paffive, with their various moods, tenfes, and perfons, must be expreffive of a like variety in the modes of thought. Things that are diftinguished in all languages, fuch as fubftance and quality, action and paffion, caufe and effect, must be diftinguished by the natural powers of the human mind. The philofophy of grammar, and that of the human understanding, are more nearly allied than is commonly imagined.

The ftructure of language was pursued to a confiderable extent, by the ancient commentators upon this book of Ariftotle. Their fpeculations upon this fubject, which are neither the leaft ingenious nor the least useful part of the Peripatetic philofophy, were neglected for many ages, and lay buried in ancient manufcripts, or in books little known, till they were lately brought to light by the learned Mr Harris in his Hermes.

The definitions given by Aristotle, of a noun, of a verb, and of speech, will hardly bear examination. It is eafy in practice to diftinguish the various parts of fpeech; but very difficult, if at all poffible, to give accurate definitions of them.

He obferves juftly, that befides that kind of fpeech called a propofition, which is always either

true

true or falfe, there are other kinds which are neither true nor falfe; fuch as, a prayer, or wish; to which we may add, a queftion, a command, a pro-mise, a contract, and many others. Thefe Ariftotle pronounces to have nothing to do with his fubject, and remits them to oratory, or poetry ;; and so they have remained banished from the regions of philofophy to this day: yet I apprehend, that an analysis of fuch fpeeches, and of the opera tions of mind which they exprefs, would be of real use, and perhaps would discover how imperfect an enumeration the logicians have given of the powers of human understanding, when they reduce them to fimple apprehenfion, judgment, and reasoning.

SECT. 6. On Propofitions.

Mathematicians ufe the word propofition in a larger fenfe than logicians. A problem is called at propofition in mathematics, but in logic it is not a propofition: it is one of thofe fpeeches which are not enunciative, and which Ariftotle remits to oratory or poetry.

A propofition, according to Ariftotle, is a speech wherein one thing is affirmed or denied of another. Hence it is eafy to diftinguith the thing af firmed or denied, which is called the predicate, from the thing of which it is affirmed or denied, which is called the Subject; and thefe two are call

ed the terms of the propofition. Hence likewife it appears, that propofitions are either affirmative or negative; and this is called their quality. All affirmative propofitions have the fame quality, fo likewise have all negative; but an affirmative and a negative are contrary in their quality.

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

two.

There are also fingular propofitions, which have not a general term but an individual for their fubject; as, Alexander was a great conqueror. These are confidered by logicians as universal, because, the fubject being indivifible, the predicate is affirmed or denied of the whole, and not of a part only. Thus all propofitions, with regard to qua

lity, are either affirmative or negative; and with. regard to quantity, are univerfal or particular; and taking in both quantity and quality, they are univerfal affirmatives, or universal negatives, or particular affirmatives, or particular negatives, These four kinds, after the days of Ariftotle, came to be named by the names of the four firft vowels, A, E, I, O, according to the following diftich:

Afferit A, negat E, fed univerfaliter ambæ ;

Afferit 1, negat 0, fed particulariter ambo,

When the young logician is thus far inftructed in the nature of propofitions, he is apt to think there is no difficulty in analyfing any propofition, and fhewing its fubject 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 analyfis, which are overlooked by Ariftotle altogether; and although they are fometimes touched, they are not removed by his followers. For, 1. There are propofitions in which it is difficult to find a fubject and a predicate; as in thefe, It rains, It fnows. 2. In fome propofitions either term may be made the fubject or the predicate as you like beft; as in this, Virtue is the road to happiness. 3. The fame example may ferve to fhew, that it is fometimes difficult to fay, whether a propofition be universal or particular. 4. The quality of fome propofitions is fo dubious, that logicians have never been able to agree whether they be affirmative