deceit and evil are often cloathed in the fhapes and appearances of truth and goodness. Now logic helps us to ftrip off the outward difguife of things, and to behold them and judge of them in their own nature.

There is yet a farther proof of our intellectual or rational powers needing fome affiftance, and that is, because they are fo frail and fallible in the present state: We are impofed upon at home as well as abroad; we are deceived by our fenfes, by our imaginations, by our paflions and appetites; by the authority of men, by education and custom, &c; and we are led into frequent errors, by judging according to these false and flattering principles, rather than according to the nature of things. Something of this frailty is owing to our very conftitution, man being compounded of flesh and fpirit; fomething of it arifes from our infant ftate, and our growing up by fmall degrees to manhood; fo that we form a thousand judgments before our reason is mature. But there is ftill more of it owing to our original defection from God, and the foolish and evil difpofitions that are found in fallen man; fo that one great part of the defign of logic is to guard us against the delufive influences of our meaner powers, to cure the mistakes of immature judgment, and to raife us in fome measure from the ruins of our fall.

It is evident enough from all these things, that our reason needs the affiitance of art in our inquiries after truth or duty and without fome skill and diligence in forming our judgment aright, we fhall be led into frequent mistakes, both in matters of fcience, and in matters of practice; and fome of these mistakes may prove fatal too.

The art of logic, even as it affifts us to gain the knowledge of the fciences, leads us on towards virtue and happinefs; for all our fpeculative acquaintance with things fhould be made fubfervient to our better conduct in the civil and the religious life. This is infinitely more valuable than all fpeculations, and a wife man will ufe them chiefly for this better purpose,

All the good judgment and prudence that any man exerts in his common concerns of life, without the advantage of learning, is called natural logic; and it is

but a higher advancement, and a farther affiftance of our rational powers, that is defigned by and expected from this artificial logic.

In order to attain this, we must inquire what are the principal operations of the mind which are put forth in the exercife of our reafon; and we fhall find them to be thefe four, viz. Perception, judgment, argumenta tion, and difpofition.

Now the art of logic is compofed of thofe obferva tions and rules, which men have made about these four operations of the mind, perception, judgment, reafone. ing, and difpofition, in order to aflift and improve: them.

I. PERCEPTION, conception, or apprehenfion, is the mere fimple contemplation of things offered to our mind, without affirming or denying any thing concern ing them. So we conceive or think of a horse, a tree, high, fwift, flow, animal, time, motion, matter, mind, life, death, &c. The form under which these things. appear to the mind, or the refult of our conception or apprehenfion, is called an idea.

II. JUDGMENT is that operation of the mind, where by we join two or more ideas together by one affirmation or negation; that is, we either affirm or deny this. to be that. So this tree is high; that horfe is not fwift; the mind of man is a thinking being; mere matter has no thought belonging to it; Gou is just ; good men are often miferable in this world; a righteous. governor will make a difference betwixt the evil and the good; which fentences are the effect of judgment and are called Propofitions.

III. ARGUMENTATION or reafoning is that operation. the mind, whereby we infer one thing, that is, onepropofition from two or more propofitions premised : or it is the drawing a conclufion, which before was either unknown, or dark or doubtful, from fome propofitions which are more known and evident. So when we have judged that matter cannot think, and

that the mind of man doth think, we then infer and conclude that therefore the mind of man is not matter.

So we judge that a just governor will make a difference between the evil and the good; we judge also that God is a juft governor; and from thence we conclude, that God will make a difference betwixt the evil and the good.

This argumentation inay be carried on farther; thus, God will one time or another make a difference between the good and the evil; but there is little or no difference made in this world: Therefore there must be another world wherein this difference fhall be made.

Thefe inferences or conclufions are the effects of reasoning; and the three propofitions taken all together are called a fyllogifm or argument.

IV. DISPOSITION is that operation of the mind, whereby we put the ideas, propofitions, and arguments, which we have formed concerning one fubject, into fuch an order as is fitteft to gain the cleareft knowledge of it, to retain it longeft, and to explain it to others in the best manner; or, in fhort, it is the ranging of our thoughts in fuch order as is best for our own and others conception and memory. The effect of this operation is called method. This very defcription of the four operations of the mind, and their effects in this order. is an instance or example of method.

Now, as the art of logic affifts our conception, so it gives us a large and comprehenfive view of the subjects we inquire into, as well as a clear and diftinct knowledge of them. As it regulates our judgment and our reafoning, so it fecures us from miftakes, and gives us a true and certain knowledge of things; and as it furnishes us with method, fo it makes our knowledge of things both eafy and regular, and guards our thoughts from confusion.

Logic is divided into four parts, according to these four operations of the mind, which it directs, and therefore we fhall treat of it in this order.

1

THE

FIRST PART

OR

LOGI C

Of PERCEPTION and IDEAS.

HE first part of logic contains obfervations and precepts about the firft operation of the mind, perception, or conception; and fince all our knowledge, how wide and large foever it grow, is founded upon our conceptions and ideas, here we fhall confider,

1. The general nature of them.

2. The objects of our conception, or the archetypes or patterns of these ideas.

3. The feveral divifions of them.

4. The words and terms whereby our ideas are expreffed.

5. General directions about our ideas.

6. Special rules to direct our conceptions.