to treat briefly of the Doctrine of Topics or Places whence middle Terms or Arguments are drawn.

All Arts and Sciences have some general Subjects which belong to them, which are called Topics, or common Places; because middle Terms are borrowed, and Arguments derived from them for the Proof of their various Propositions which we have occasion to discourse of. The Topics of Grammar are Etymology, Noun, Verb, Construction, Signification, &c. The Topicks of Logic are Genus, Species, Difference, Property, Definition, Division, &c. The Topics of Ontology or Metaphysics are Çause, Effect, Action, Passion, Identity, Opposition, Subject, Adjunet, Sign, &c. The Topics of Morality or Ethics are Law, Sin, Duty, Authority, Freedom of Will, Command, Threatning, Reward, Punishment, &c. The Topics of

, Theology are God, Christ, Faith, Hope, Worship, Salvation, &c.

To these several Topics there belong particular Observations, Axioms, Canons or Rules *, which are laid down in their proper Sciences; as,

Grammar hath such Canons, (viz.) Words in a different Construction obtain a different Sense. Words derived from the same Primitive may probably have Some Afinity in their original Meaning, &c.

Canons in Logic are such as these, Every Part of a Division singly taken must contain less than the Whole. À Definition must be peculiar and proper to the Thing defined. Whatever is affirmed or deni:d of the Genus, may be affirmed or denied of the Species, &c.

Metaphysical Canons are such as these ; final Causes belong only to intelligent Agents. If a natural and necessary Cause operate, the Effect will follow,

* A Canon is a Proposition declaring some Property of the Subject, which is not exprcft in the Definition or Division of ito

&c.

&c. and there are large Catalogues of many more in each distinct Science.

Now it has been the Cuftom of those who teach Logick or Rhetorick to direct their Difciples, when they want an Argument, to confult the feveral Topics which are fuited to their Subject of Difcourfe, and to rummage over the Definitions, Divifions and Canons that belong to each Topic. This is called the Invention of an Argument; and it is taught with much Solemnity in fome Schools.

I grant there may be good Úfe of this Practice for Perfons of a lower Genius, when they are to compofe any Difcourfe for the Publick; or for thofe of fuperior Parts to refresh their Memory, and revive their Acquaintance with a Subject which has been long abfent from their Thoughts; or when their natural Spirits labour under Indifpofition and Languor; but when a Man of moderate Sagacity has made himself Master of his Theme by juft Diligence and Enquiry, he has seldom need to run knocking at the Doors of all the Topics that he may furnish himself with Argument or Matter of speaking: And indeed it is only a Man of Senfe and Judgment that can ufe common Places or Topics well; for amongst this Variety he only knows what is fit to be left out, as well as what is fit to be spoken.

By fome logical Writers this Bufinefs of Topics, and Invention is treated of in fuch a manner with mathematical Figures and Diagrams, filled with the barbarous technical Words, Napcas, Nipcis, Ropcos, Nofrop, &c. as tho' an ignorant Lad were to be led mechanically in certain artificial Harneffes and Trammels to find out Arguments to prove or refute any Propofition whatsoever, without any rational Knowledge of the Ideas. Now there is no Need to throw Words of Contempt on fuch a Practice;

a Practice; the very Description of it carries Reproof and Ridicule in Abundance.

SECT. VIII.

Of feveral Kinds of Arguments and Demonftrations.

WE

1. Demonstrations a Priori, which prove the Effect by its neceffary Caufe; as, I prove the Scripture is infallibly true, because it is the Word of God, who cannot lye.

2. Demonstrations a Pofteriori, which infer the Caufe from its neceffary Effect; as, I infer there bath been the Hand of fome Artificer here, because I find a curious Engine. Or, I infer there is a God, from the Works of his Wifdom in the visible World.

The last of these is called Demonftratio To T, because it proves only the Exiftence of a Thing; the first is named Demonftratio 8 díot, because it fhews alfo the Caufe of its Existence.

But Note, That tho' these two forts of Argu ments are moft peculiarly called Demonftrations, yet generally any ftrong and convincing Argument obtains that Name; and it is the Cuftom of Mathematicians to call all their Arguments Demonftrations, from what Medium foever they derive them.

III. Arguments are divided into artificial and inartificial.

An artificial Argument is taken from the Nature and Circumstances of the Things; and if the Argument be strong it produces a natural Certainty; as The World was first created by God, because nothing can create itself.

An inartificial Argument is the Testimony of another, and this is called original, when our Information proceeds immediately from the Perfons concerned, or from Eye or Ear-Witneffes of a Fact: it is called Tradition when it is delivered by the Report of others.

We have taken Notice before, that Testimony is either divine or human. If the human Testimony be strong, it produces a moral Certainty;

but divine Testimony produces a supernatural Certainty which is far superior.

Note, Arguments taken from human Testimony as well as from Laws and Rules of Equity, are called moral; and indeed the fame Name is also applied to every sort of Argument which is drawn from the free Aɛtions of God, or the contingent Actions of Men, wherein we cannot arise to a natural Certainty, but content ourselves with an high Degree of Probability, which in many Cases is scarce inferior to natural Certainty.

IV. Arguments are either direEt or indire£t. It is a direct Argument where the middle Term is such as proves the Question itself, and infers that very Proposition which was the Matter of Enquiry. An indirect or oblique Argument proves or refutes fome other Proposition, and thereby makes the Thing enquired appear to be true by plain Consequence.

Several Arguments are called indirect ; as, (1.) When some contradictory Proposition is proved to be false, improbable or impossible : Or when upon Supposition of the Falshood or Denial of the original Proposition, fome Absurdity is inferred. This is called a Proof per impossibile, or a Reductio ad absurdum. (2.) When some other Proposition is proved to be true which is less probable, and thence it follows that the original Proposition is true, because it is more probable. This is an Argument ex magis probabili ad minus. (3.) When any other Proposition is proved upon

which it was before agreed to yield the original Question. This is an Argument ex Concesso.

V. There is yet another Rank of Arguments which have Latin Names; their true Distinction