rules; and if we would gain a juft and precife idea of every univerfal, particular and indefinite expreffion, we must not only consider the particular idiom of the language, but the time, the place, the occasion, the cir cumstances of the matter spoken of, and thus penetrate as far as poffible into the design of the speaker or writer.

SECT. II..

Of affirmative and negative Propofitions.

W

HEN a proposition is considered with regard to its copula, it may be divided into affirmative and negative; for it is a copula joins or disjoins the two ideas. Others call this a division of proposition according to their quality,

An affirmative propofition is when the idea of the pre-dicate is fuppofed to agree to the idea of the subject, and is joined to it by the word is, or are, which are the copula; as, all men are sinners. But when the predicate is not fuppofed to agree with the fubject, and is disjoined from it by the particles is not, are not, &c. the proposition is negative: as, man is not innocent ;, or, no man is innocent. In an affirmative proposition we affert one thing to belong to another, and as it were, unite them in thought and word; in negative propositions we feparate one thing from another, and deny their agreement.

It may become fomething odd, that two ideas or terms are faid to be disjoined as well as joined by a copula but if we can but fuppofe the negative particles do really belong to the copula of negative proposi tions, it takes away the harfhnefs of the expreffion; and to make it yet fofter, we may consider that the predicate and fubject may be properly faid to be joined in a form of words as a proposition, by connective particles in grammar or logic, though they are disjoined in their fenfe and signification. Every youth who has

learned his grammar, knows there are fuch words as disjunctive conjunctions.

Several things are worthy of our notice on this fubject.

Note. As there are fome terms or words, and ideas, (as I have fhewn before) concerning which it is hard to determine whether they are negative or pofitive, fo there are some propofitions concerning which it may be difficult to fay, whether they affirm or deny; as, when we fay, Plato was no fool: Cicero was no unfkilful orator: Cæfar made no expedition to Mufcovy: an oyfter has no part like an eel; It is not neceffary for a phyfician to fpeak French, and for a phyfician to fpeak French is needlefs. The fense of these propofitions is very plain and easy, though logicians might fquabble perhaps a whole day, whether they fhould tank them under the names of negative or affirmative..

Note 2. In Latin and English two negatives joined in one sentence make an affirmative; as when we de clare, no man is not mortal, it is the fame as though we faid, man is mortal, but in Greek, and oftentimes. in French, two negatives make but a stronger denial.

Note 3: If the mere negative term, not, be added to the copula of an univerfal affirmative propofition, it reduces it to a particular negative; as, all men are not wife, fignifies the fame as, fome men are not wife.

Note 4 In all affirmative propofitions, the predicate is taken in its whole comprehenfion; that is, every effential part and attribute of it is affirmed concerning the fubject; as when I fay, a true chriftian is an honeft man, every thing that belongs to honefty is affirmed. concerning a true chriftian.

Note 5. In all negative propofitions the predicate is. taken in its whole extenfion: that is, every fpecies and individual that is contained in the general idea of the predicate, is utterly denied concerning the fubject; fo in this propofition, a fpirit is not an animal, we exclude all forts and kinds and particular animals whatsoever from the idea of a fpirit.

From these two laft remarks we may derive this inference, that we ought to attend to the entire comprehenfion of our ideas, and to the universal extension of

them, as far as we have proper capacity for it, before we grow too confident in our affirming or denying any thing, which may have the least darkness, doubt or difficulty attending it: it is the want of that attention that betrays us into many mistakes.

A

SECT. III.

Of the Oppofition and Converfion of Propofitions.

NY two ideas being joined or disjoined in various forms will afford us feveral propofitions: all thefe may be diftinguished according to their quantity. and their quality into four, which are marked or denoted by the letters A, E, I, O, thus:

*

A

I

}

denotes a

Univerfal affirmative.
Univerfal negative.
Particular affirmative..

Particular negative.

according to these old Latin rhymes

Afferit A, Negat E, verum generaliter amba;
Afferit 1, Negat O, fed particulariter ambo.

This may be exemplified by these two ideas, a Vine and a Tree.

A Every Vine is a Tree..

E No Vine is a Tree.
I Some Vine is a Tree.

Some Vine is not a Trees

The logicians of the fchools have written many large trifles concerning the oppofition and converfion of propo fitions. It will be fufficient here to give a few brief

*The reader fhould remember here, that a propofition according to its quantity is called univerfal or particular, and according to its quality, it is either affirmative or negative..

hints of these things, that the learner may not be utterly ignorant of them.

Propofitions which are made of the fame subject and predicate are faid to be oppofite, when that which is denied in one is affirmed in the other, either in whole or in part, without any confideration whether the propofitions be true or no.

If they differ both in quantity and quality, they are faid to be contradictory; as,

A Every Vine is a

Free

Some Vine is not

a Tree.

These can never be both true, or

both falfe at the fame time.

If two univerfals differ in quality, they are contraries; as,

A Every Vine is a Tree.

E No Vine is a

Tree.

These can never be both true toge

ther, but they may be both falfe.

If two particular propofitions differ in quality, they are fubcontraries; as,

I Some Vine is a

Tree.

Some Vine is not

a Tree.

}

Thefe may be both true together, but they can never be both falfe.

Both particular and univerfal propositions which agree in quality, but not in quantity, are called fubaltern, though these are not properly opposite, as

A Every Vine is a Tree.

I Some Vine is a Tree.

Or thus:

E No Vine is a Tree.

O Some Vine is not a Tree.

The canons of fubaltern propofitions are ufually reckoned these three, (viz) (1). If any univerfal propofition be true, the particular will be true alfo, but not on the contrary. And (2) If a particular propofition be falfe, the universal must be false, but not on the contrary. (3.) Subaltern propofitions, whether univerfal or particular, may fometimes be both true, and fometimes both falfe.

The converfion of propofitions is when the fubject

and predicate change their places with prefervation of the truth. This may be done with conftant certainty in all univerfal negatives and particular affirmatives; as, no fpirit is an animal, may be converted, no animal is a fpirit; and fome tree is a vine, may be converted, fome vine is a tree. But there is more formal trifling in this fort of difcourfe than there is of folid improvement, because this fort of converfion arifes merely from the form of words, as connected in a propofition, rather than from the matter.

Yet it may be useful to obferve, that there are some propofitions, which by reafon of the ideas or matter of which they are compofed may be converted with conftant truth fuch are those propofitions whofe predicate is a nominal or real definition of the subject, or the difference of it, or a property of the fourth kind, or a fuperlative degree of any property or quality whatfoever, or in fhort, wherefoever the predicate and the fubject have exactly the fame extenfion or the fame comprehenfion; as, every vine is a tree bearing grapes; and every tree bearing grapes is a vine: religion is the trueft wisdom, and the trueft wisdom is religion: Julius Cæfar was the first emperor of Rome; and the first emperor of Rome was Julius Cæfar. Thefe are the propofitions which are properly convertible, and they are called reciprocal propositions.

A

SECT. IV.

Of pure and modal Propofitions.

NOTHER divifion of propofitions among the fcholaftic writers is into pure and modal. This may be called (for distinction fake) a divifion accord ing to the predicate.

When a propofition merely expreffes that the predicate is connected with the fubject, it is called a pure propofition; as, every true chriftian is an honeft man.