Now the defign of Logick is to teach us the right ufe of our reafon, or intellectual powers, and the improvement of them in ourfelves and others; this is not only neceffary in order to attain any competent knowledge in the fciences, or the affairs of learning, but to govern both the greater and the meaner actions of life. It is the cultivation of our reafon by which we are better enabled to distinguish good from evil, as well as truth from falfehood: and both these are matters of the highest importance, whether we regard this life, or the life to come. The purfuit and acquifition of truth is of infinite concernment to mankind. Hereby we become acquainted with the nature of things both in heaven and earth, and their various relations to each other. It is by this means we discover our duty to God and our fellow-creatures: by this we arrive at the knowledge of natural religion, and learn to confirm our faith in divine revelation, as well as to understand what is revealed. Our wisdom, prudence and piety, our present conduct and our future hope, are all influenced by the use of our rational powers in the fearch after truth. There are feveral things that make it very neceffary that our reafon fhould have fome affiftance in the exercife or use of it. This firft is, the depth and difficulty of many truths, and the weakness of our reafon to fee far into things at once, and penetrate to the bottom of them. It was a faying among the ancients, Veritas in puteo, "Truth lies in a well;" and, to carry on this metaphor, we may very juftly fay, that Logick does, as it were, supply us with feps whereby we may go down to reach. the water; or it frames the links of a chain, whereby we may draw the water up from the bottom. Thus, by the means of many reafonings well connected together, philofophers in our age have drawn a thousand truths out of the depths of darknefs, which our fa thers were utterly unacquainted with. Another Another thing that makes it neceffary for our reafon to have some affistance given it, is the difguife and false colours in which many things appear to us in this prefent imperfect fate. There are a thousand things which are not in reality what they appear to be, and that both in the natural and the moral world: fo the Jun appears to be flat as a plate of filver, and to be less than twelve inches in diameter: the moon appears to be as big as the fun, and the rainbow appears to be a large fubftantial arch in the fky; all which are in reality grofs falfehoods. So knavery puts on the face of justice, bypocrify, and fuperftition wear the vizard of piety, deceit and evil are often clothed in the shapes and appearances of truth and goodness. Now Logick helps to ftrip off the outward disguise of things, and to behold them, and judge of them in their own nature. There is yet a farther proof that our intelle&ual or rational powers need fome affiftance, and that is, because they are fo frail and fallible in the present ftate; we are impofed upon at home as well as abroad; we are deceived by our fenfes, by our imaginations, by our paffions and appetites, by the authority of men, by education and cuftom, 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, so that we form a thoufand judgments before our reafon 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 Logick is to guard us against the delufive influences of our meaner powers, to cure the miftakes 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 reafon needs the affiftance of art in our inquiries after truth truth or duty; and without fome skill and diligence in forming onr judgments aright, we fhall be led into fre quent mistakes, both in matters of Science and in matters of practice, and some of these mistakes may prove fatal too. The art of Logick, even as it affifts us to gain the knowledge of the fciences, leads us on toward virtue and happiness: for all our fpeculative acquaintance with things fhould be made fubfervient to our better conduct in the civil and religious life. This is infinitely more valuable than all fpeculations; and a wife 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 ad vantage of learning, is called natural logick; and it is but a higher advancement, and a farther affistance of our rational powers, that is defigned by and expected from this artificial Logick. 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 shall find thers to be thefe four, namely, perception, judgment, argumentation and difpofition. Now the art of Logick is composed of those observarious and rules, which men have made about these four operations of the mind, perception, judgment, reafoning, and difpofition, in order to affift and improve them. 1. Perception, conception, or apprehenfion, is the mere Ample contemplation of things offered to our minds, without affirming or denying any thing concerning them. So we conceive or think of a bore, a tree, high, fwift, flow, animal, time, motion. matter, mind, fe, death, &c. The form under which thefe 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, whereby we join two or more ideas together by one affirma tion tion 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; God is juft; 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 of the mind, whereby we infer one thing, that is, one propofition, from two or more propofitions premifed. 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 just governor; and from thence we conclude, that God will make a difference between the evil and the good. This argumentation may 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. Thefe inferences or conclufions are the effects of reafoning, and the three propofitions taken all together are called a fyllogifm or argument. IVJ Difpofition 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 clearest knowledge of it, to retain it longeft, and to explain it to others in the heft 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 opera tion tion is called method. This very defcription of the four operations of the mind and their effects, in this order, is an inftance or example of method. Now as the art of Logick affifts our conceptions, fo it gives us a large and comprehenfive view of the fubjects we enquire into, as well as a clear and distinct knowledge of them. As it regulates our judgment and our reafoning, so it fecures us from mistakes, 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 confufion. Logick 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. THE |
