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deceit and evil are often cloathed in the shapes and appearances of truth and goodness. Now logic helps us to strip off the outward disguise 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 affistance, and that is, because they are so frail and fallible in the present state : We are imposed upon at home as well as abroad; we are deceived by our senses, 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 fiesh and spirit ; something of it arises from our infant state, and our growing up by small degrees to manhood ; so that we form a thousand judgments before our reason is mature. But there is still more of it owing to our original defection from God, and the foolish and evil dispositions that are found in fallen man; so that one great part of the design of logic is to guard us againit the delusive influences of our meaner powers, to cure the mistakes of immature judgment, and to raise us in fome measure from the ruins of our fall. :
It is evident enough from all these things, that our reason needs the assistance of art in our inquiries after truth or duty; and without some skill and diligence in forming our judgment aright, we shall be led into frequent mistakes, both in matters of science, and in mata ters of practice; and some of these mistakes may prove fatal too.
The art of logic, 'even as it affifts us to gain the knowledge of the sciences, leads us on towards yirtue and happiness; for all our speculative acquaintance with things Thould be made subservient to our better conduct in the civil and the religious life. This is infinitely more valuable than all speculations, and a wise man will use 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 assistance of our rational powers, that is designed 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 exercise of our reason; and we shall find them to be these four, viz. Perception, judgment, argumenta.. tion, and disposition.
Now the art of logic is composed of those observada. tions and rules, which men have made about these four operations of the mind, perception, judgment, reafon ing, and difpofition, in order to afliit and improve: them.
1. PERCEPTION, conception, or apprehension, is the mere simple contemplation of things offered to our mind, without affirming or denying any thing concerne ing them. So we conceive or think of a horse, a tree, high, swift, flow, animal, time, motion, matter, mind, life, death, &c. The form under which these things appear to the mind, or the result of our conception or apprehenfion, is called an idea. ..
11. JUDGMENT is that operation of the mind, wherea by we join two or more ideas together by one affirma-. tion or negation; that is, we either affirm or deny this, to be that. So this tree is high; that horse is not fwift; the mind of man is a thinking being; mere matter has no thought belonging to it; Goud is just; good men are often miserablein this world; a righteous, governor will make a difference betwixt-the evil and the good; which sentences are the effect of judgment and are called Propofitions.
III. ARGUMENTATION or reasoning is that operation the mind, whereby we infer one thing, that is, one proposition from two or more propositions premised: or it is the drawing a conclusion, which before was either unknown, or dark or doubtful, from some propositions 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 just 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 shall be made.
These inferences or conclusions are the effects of reasoning; and the three propositions taken all together are called a syllogism or argument.
IV. DISPOSITION is that operation of the mind, whereby we put the ideas, propositions, and arguments, which we have formed concerning one subject, into such an order as is fitteft to gain the clearest knowledge of it, to retain it longeft, and to explain it to others in the best manner; or, in short, it is the ranging of our thoughts in such order as is best for our own and others conception and memory. The effect of this operation is called method. This very description 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 assists our conception, so it gives us a large and comprehensive view of the subjects we inquire into, as well as a clear and distinct knowledge of them. As it regulates our judgment and our reasoning, so it fecures us from mistakes, and gives us a true and certain knowledge of things ; and as it furnishes us with method, so it makes our knowledge of things both easy 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 thall treat of it in this order.
LOG I C.
Of PERCEPTION and. IDEAS.
*THE first part of logic contains observations and
I precepts about the first operation of the mind, perception, or conception; and since all our knowledge, how wide and large foever it grow, is founded upon our conceptions and ideas, here we shall consider,
1. The general nature of them. • 2. The objects of our conception, or the archetypes or patterns of these ideas.
3. The several divisions of them. : 4. The words and terms whereby our ideas are ex. pressed.
5. General directions about our ideas.