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Of Invention in general, and particularly of
Common Places.

Invention, considered in general, is the discovery of such things as are proper to persuade. And in order to attain this end, the orator proposes to himself three things; to prove or illustrate the subject upon which he treats, to conciliate the minds of his hearers, and to engage their passions in his favour. And as these require different kinds of arguments or motives, invention furnishes him with a supply for each of them, as will be shown in their order.

I shall first consider that part of Invention which directs to arguments proper for the proof of a thing; which, as Cicero tells us, is, "the dis

covery of such things as are really true, or "that seem to be so, and make the thing, for "which they are produced, appear probable." And the things, which are thus discovered, are called Arguments; for," an Argument," as defined by him," is a reason, which induces us to "believe what before we doubted of." If we reflect upon those things, which relate to the common affairs of life, and the numerous transactions between mankind, we shall find that most of them are of a dubious nature, and liable to various constructions, as they are taken in different views; from whence a diversity of opinions is formed concerning them. And where the nature of the thing does not admit of certainty, every considerate and prudent person will give into that side of the question which carries in it the greater degree of probability. And as these are the subjects with which the ancient orators were principally concerned, we

find, by Cicero's definition, that all he requires of such arguments as they commonly made use of, is to render a thing probable. Indeed there are some things which do not so much require reasoning, as a proper and suitable manner of representing them, to make them credible; and because the several ways of illustrating these are also taught by the precepts of this art, they are likewise, in a large sense of the word, called arguments.

But as different kinds of discourses require different arguments, rhetoricians have considered them two ways; in general, under certain heads, as a common fund for all subjects; and in a more particular manner, as they are suited to demonstrative, deliberative, or judicial discourses. At present I shall treat only upon the former of these. And now, that one thing may receive proof and confirmation from another, it is necessary that there be some relation between them; for all things are not equally adapted to prove one another.

That we may the better conceive this, I shall make use of a plain and familiar instance. In measuring the quantity of two things which we wquld show to be either equal or unequal, if they are of such a nature that one cannot be applied to the other, then we take a third thing, which may be applied to them both, and that must be equal at least to one of the two, which, if applied to the other, and found equal to that also, we presently conclude that those two things are equal; but if it be unequal to the other, we say that those two things are unequal. Because it is the certain and known property of all quantities, that whatsoever two things are

equal to a third, are equal to one another; and where one of any two things is equal to a third, and the other unequal, those two things are unequal to one another. What has been said of quantities will hold true in all other cases,-that so far as any two things or ideas agree to a third, so far they agree to one another. And by agreeing, I understand this, that the one may be affirmed of the other. So likewise on the contrary, as far as one of any two things or ideas does agree to a third, and the other does not, so far they disagree with one another, in which respect one of them cannot be truly affirmed of the other. Since therefore in every proposition one thing is spoken of another, if we would find out whether the two ideas agree to each other or not, where this is not evident of itself, we must find out some third thing, the idea of which agrees to one of them; and then that being applied to the other, as it does agree or disagree with it, so we may conclude that the two things proposed do agree or disagree with one another.

This will be made more clear by an example or two. Should it be inquired, Whether virtue is to be loved? the agreement between virtue and love might be found by comparing them separately with happiness, as a common measure to both. For since the idea of happiness agrees to that of love, and the idea of virtue to that of happiness, it follows that the ideas of virtue and love agree to one another; and therefore it may be affirmed, That virtue is to be loved. But on the contrary, because the idea of misery disagrees with that of love, but the idea of vice agrees to that of misery, the two ideas of vice

and love must consequently disagree with one another; and therefore it would be false to assert, That vice is to be loved. Now this third thing logicians call the medium or middle term, because it does as it were connect two extremes, that is, both parts of a proposition. But rhetoricians call it an argument, because it is so applied to what was before proposed, as to be come the instrument of procuring our assent to it. I have mentioned these plain examples only for illustration, by which we may in some measure perceive the nature and use of arguments.

But from whence, and by what methods they are to be sought, I shall now explain.

A lively imagination and readiness of thought are undoubtedly a very great help to invention. Some persons are naturally endued with that quickness of fancy and penetration of mind, that they are seldom at a loss for arguments either to defend their own opinions, or to attack their adversaries. However these things being the gift of nature, and not to be gained by art, do not properly fall under our present consideration.

But because all are not born with a like happy genius, and have not the same opportunity to cultivate their minds with learning and knowledge, and because nothing is more difficult than to dwell long upon the consideration of one thing, in order to find out the strongest arguments which may. be offered for and against it, upon these accounts art has prescribed a method to lessen in some measure these difficulties, and help every one to a supply of arguments upon any subject. And this is done by the contrivance of common places, which Cicero

calls the seats or heads of arguments, and, by a Greek name, topics. They are of two sorts, internal and external. As to the former, though things with regard to their nature and properties are exceedingly various, yet they have certain common relations, by means whereof the truth of what is either affirmed or denied concerning them in any respect may be evinced. The ancient Greek rhetoricians therefore reduced these relations to some general heads; which are termed common places, because the reasons or arguments suited to prove any proposition are reposited in them, as a common fund or receptacle. And they are called internal heads, because they arise from the subject upon which the orator treats; and are therefore distinguished from others named external, which he fetches from without, and applies to his present purpose, as will be shown hereafter. Cicero and Quintilian make them sixteen; three of which comprehend the whole thing they are brought to prove; namely, Definition, Enumeration, and Notation; and of the remaining thirteen some contain a part of it, and the rest its various properties and circumstances, with other considerations relating to it; and these are Genus, Species, Antecedents, Consequents, Adjuncts, Conjugates, Cause, Effect, Contraries, Opposites, Similitude, Dissimilitude, and Comparison. I shall give a brief account of each of these, in the order now mentioned.

DEFINITION Explains the nature of the thing defined, and shows what it is. And to whatsoever the definition agrees, the thing defined does so likewise. If therefore Socrates be a rational creature, he is a man; because it is the definition of a man that he is a rational creature

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