(3.) When we would prove the importance of any scriptu-, ral doctrine or duty, the multitude of texts, wherein it is repeated and inculcated upon the reader, seems naturally to instruct us that it is a matter of greater importance, than other things which are but slightly or singly mentioned in the Bible.

(4.) In searching out matters of fact in times past, or in distant places, in which case moral evidence is sufficient, and moral certainty is the utmost which can be attained, here we derive a greater assurance of the truth of it by a number of persons, or a multitude of circumstances concurring to bear witness to it.

(5.) From many experiments in natural philosophy, we more safely infer a general theorem, than we can from one or two.

(6.) In matters which require present practice, both sacred and civil, we must content ourselves oftentimes with a mere preponderation of probable reasons or arguments. Where there are several reasons on each side, for and against a thing that is to be done or omitted, a small argument added to the heap may justly turn the balance on one side, and determine the judgment, as I have noted in the Second Part of Logic.

To conclude; a growing acquaintance with matters of learning, and a daily improvement of our understandings in affairs human and divine, will best teach us to judge and distinguish in what cases the number of arguments adds to their weight and force. It is only experience can fully inform us when we must be determined by probable topics, and when we must seek and expect demonstrations.

VI. "Prove your conclusion (as far as possible) by some propositions that are in themselves more plain, evident, and certain, than the conclusion; or at least such as are more known, and more intelligible to the person whom you would convince." If we neglect this rule, we shall endeavour to enlighten that which is obscure by something equally or more obscure, and to confirm that which is doubtful by something equally or more un certain. Common sense dictates to all men, that it is impossible to establish any truth, and to convince others of it, but by something that is better known to them than that truth is.

VII. "Labour in all your arguings to enlighten the understanding, as well as to conquer and captivate the judgment." Argue in such a manner as may give a natural, distinct, and solid knowledge of things to your hearers, as well as to force their assent by a mere proof of the question. Now to attain this end, the chief topic or medium of your demonstration should be fetched as much as possible, from the nature of the thing to be proved, or from those things which are most naturally connected with it. Geometricians sometimes break this rule without necessity, two ways; namely,

1. When they prove one proposition only by shewing what absurdities will follow if the contradictory proposition be supposed or admitted. This is called reductio ad absurdum*, or demonstratio impossible. As for instance, when they prove all the radi of a circle to be equal, by supposing one radius to be longer or shorter than another, and then shewing what absurd consequences will follow. This, I confess, forces the assent, but it does not enlighten the mind, by shewing the true reason and cause why all radii are equal, which is derived from the very construction of a circle for since a circle is formed by fixing one end of a straight line in the centre, and moving the other end round, (or, which is all one, by compasses kept open to a certain extent) it follows evidently that every part of the circumference being thus described, must be equally distant from the centre, and therefore the radii, which are lines from the centre to the circumference must be all equal.

2. Geometricians forget this rule, when they heap up many far-fetched lines, figures and propositions, to prove some plain, simple, and obvious propositions. This is called a demonstration per aliena & remota, or an argument from unnatural and remote mediums; as if, in order to prove the radii of a circle are all equal, I should make several triangles and squares about the circle, and then from some properties and propositions of squares and triangles prove that the radii of a circle are equal.

Yet it must be confessed, that sometimes such questions happen, that it is hardly possible to prove them by direct arguments drawn from the nature of things, &c. and then it may not only be lawful but necessary to use indirect proofs, and arguments drawn from remote mediums, or from the absurdity of the contradictory suppositions.

Such indirect and remote arguments may also be sometimes used to confirm a proposition, which has been before proved by arguments more direct and immediate.

VIII. Though arguments should give light to the subject, as well as constrain the assent, yet you must learn to "distinguish well between an explication and an argument, and neither inpose upon yourselves, nor suffer yourselves to be imposed upon by others, by mistaking a mere illustration for a convincing

reason.

Axioms themselves, or self-evident propositions, may want an explication or illustration, though they are not to be proved by reasoning.

*Note, This rule chiefly refers to the establishment of some truth, rather than to the refutation of error. It is a very common and useful way of arguing, ts refute a false proposition, by shewing what evident falsehood or absurdity will follow from it ; for what proposition soever is really absurd and false, does effectually prove that principle to be false from which it is derived, so that this way of refuting an error is not so usually called reductio ad absurdum.

Similitudes and allusions have oftentimes a very happy influence to explain some difficult truth, and to render the idea of it familiar and easy. Where the resemblance is just and accurate, the influence of a simile may proceed so far as to shew the possibility of the thing in question: but similitudes must not be taken as a solid proof of the truth or existence of those things to which they have a resemblance. A too great deference paid to similitudes, or an utter rejection of them, seem to be two extremes, and ought to be avoided. The late ingenious Mr. Locke, even in his Enquiries after truth, makes great use of similies for frequent illustration, and is very happy in the invention of them, though he warns us also lest we mistake them for conclusive arguments.

Yet let it be noted here, that a parable or a similitude used by any author, may give a sufficient proof of the true sense and meaning of that author, provided that we draw not this similitude beyond the scope and design for which it was brought; as when our Saviour affirms; Rev. iii. 3. I will come on thee as a thief! this will plainly prove that he describes the unexpectedness of his appearance, though it is by no means to be drawn to signify any injustice in his design.

IX. "In your whole course of reasoning keep your mind sincerely intent on the pursuit of truth; and follow solid argument wheresoever it leads you." Let not a party spirit, nor any passion or prejudice whatsoever, stop or avert the current of your reasoning in quest of true knowledge.

When you are enquiring therefore into any subject, maintain a due regard to the arguments and objections on both sides of a question, Consider, compare, and balance them well, before you determine for one side. It is a frequent, but a very faulty practice, to hunt after arguments only to make good one side of question, and entirely to neglect and refuse those which favour the other side. If we have not given a due weight to arguments on both sides, we do but wilfully misguide our judgment, and abuse our reason, by forbidding its search after truth. When we espouse opinions by a secret bias on the mind, through the influence of fear, hope, honour, credit, interest, or any other prejudice, and then seek arguments only to support those opinions, we have neither done our duty to God nor to ourselves; and it is a matter of mere chance if we stumble upon truth in our way to ease and preferment. The power of reasoning was given us by our Maker for this very end, to pursue truth; and we abuse one of his richest gifts, if we basely yield it up to be led astray by any of the meaner powers of nature, or the perishing interests of this life. Reason itself, if honestly obeyed, will lead us to receive the divine revelation of the gospel, where it is duly proposed, and this will show us the path of life everlasting.

THE FOURTH PART OF LOGIC.

Of Disposition and Method.

IT is not merely a clear and distinct idea, a well-formed proposition, or a just argument, that is sufficient to search out and communicate the knowledge of a subject. There must be a variety and series of them disposed in a due manner, in order to attain this end; and therefore it is the design of the last part of Logic, to teach us the art of method. It is that must secure our thoughts from that confusion, darkness and mistake, which unavoidably attend the meditations and discourses even of the brightest genius who despises the rules of it.

I. We shall here consider the nature of method, and the several kinds of it.-II. Lay down the general rules of method, with a few particulars under them.

CHAP. I.-Of the Nature of Method and the several Kinds of it, namely, Natural and Arbitrary, Synthetic and Analytic.

METHOD, taken in the largest sense implies the "placing of several things, or performing several operations, in such an order, as is most convenient to attain some end proposed:" and in this sense it is applied to all the works of nature and art, to all the divine affairs of creation and providence; and to the artifices, schemes, contrivances, and practices of mankind, whether in natural, civil, or sacred affairs.

Now this orderly disposition of things includes the ideas of prior, posterior, and simultaneous; of superior, inferior, and equal; of beginning, end, and middle, &c. which are described more particularly among the general affections of being, in ontology.

But in Logic method is usually taken in a more limited sense, and the nature of it is thus described: "Method is the disposition of a variety of thoughts on any subject, in such order as may best serve to find out unknown truths, to explain and confirm truths that are known, or to fix them in the memory."

It is distributed into two different kinds, namely, natural and arbitrary.

Natural method is that which observes the order of nature, and proceeds in such a manner, as that the knowledge of the things which follows, depends in a great measure on the

things which go before, and this is two-fold, viz. synthetic and analytic, which are sometimes called synthesis and analysis.*

Synthetic method is that which begins with the parts,† and leads onward to the knowledge of the whole; it begins with the most simple principles, and general truths, and proceeds by degrees to that which is drawn from them, or compounded of them; and therefore it is called the method of composition.

Analytic method takes the whole compound as it finds it, whether it be a species or an individual, and leads us into the knowledge of it, by resolving it into its first principles or parts, its generic nature, and its special properties; and therefore it is called the method of resolution.

As synthetic method is generally used in teaching the sciences after they are invented, so analytic is most practised in finding out things unknown. Though it must be confessed, that both methods are sometimes employed to find out truth and to communicate it.

If we know the parts of any subject easier and better than the whole, we consider the parts distinctly, and by putting them together, we come to the knowledge of the whole. So in grammar, we learn first to know letters, we join them to make syllables, out of syllables we compose words, and out of words we

The word analysis has three or four senses, which it may not be improperto take notice of here.

1. It signifies the general and particular heads of a discourse, with their mutual connection, both co-ordinate and subordinate, drawn out by way of abstract into one or more tables, which are frequently placed like an index at the beginning or end of a book.

2. It signifies the resolving of a discourse into its various subjects and argum ments, as when any writing of the ancient prophets is resolved into the prophetical, historical, doctrinal, and practical parts of it; it is said to be analysed in general. When a sentence is distinguished into the nouns, the verbs, pronouns, adverbs, and other particles of speech which compose it, then it is said to be analysed grammatically. When the same sentence is distinguished into subject *predicate, proposition, argument, act, object, cause, effect, adjunct, opposite, &c. then it is analysed logically, and metaphysically. This last is what is chiefly meant in the theological schools, when they speak of analysing a text of scripture.

3. Analysis signifies particularly the science of Algebra, wherein a question being proposed, one or more letters, as x, y, z, or vowels, as a, e, i, &c. are made use of to signify the unknown number, which being intermingled with several known numbers in the question, is at last, by the rules of art, separated or released from that entanglement, and its particular value is found out by shewing its equation, or equality to some known number.

4. It signifies analytical method, as here explained in Logic.

Note. It is confessed that synthesis often begins with the genus, and proceeds to the species and individuals. But the genus or generic nature is then considered only as a physical or essential part of the species, though it be sometimes called an universal, or logical whole. Thus synthetic method maintains its own description still, for it begins with the parts, and proceeds to the whole, which is composed of them.,