Imágenes de páginas

logifm. A remarkable property of this kind is, that it may fometimes be happily retorted: it is, it feems, like a hand-grenade, which by dextrous management may be thrown back, fo as to fpend its force upon the affailant. We fhall conclude this tedious account of fyllogifins, with a dilemma mentioned by A. Gellius, and from him by many logicians, as infoluble other way.

in any

"Euathlus, a rich young man, defirous "of learning the art of pleading, applied

[ocr errors]

to Protagoras, a celebrated fophift, to "inftruct him, promifing a great fum of money as his reward; one half of which was paid down; the other half he bound himself to pay as foon as he "fhould plead a caufe before the judges, "and gain it. Protagoras found him a

[ocr errors]
[ocr errors]

very apt fcholar; but, after he had "made good progrefs, he was in no hafte

to plead caufes. The mafter, concei"ving that he intended by this means to "fhift off his fecond payment, took, as "he thought, a fure method to get the "better of his delay. He fued Euathlus "before the judges; and, having opened

"his caufe at the bar, he pleaded to this


3 D



"purpose. O most foolish young man, "do you not see, that, in any event, I "must gain my point? for if the judges "give fentence for me, you must pay by "their sentence; if against me, the con"dition of our bargain is fulfilled, and


you have no plea left for your delay,

"after having pleaded and gained a cause. "To which Euathlus anfwered. O most "wife mafter, I might have avoided the "force of your argument, by not pleading my own caufe. But, giving up this advantage, do you not fee, that whatever fentence the judges pafs, I am safe? "If they give sentence for me, I am ac"quitted by their fentence; if against me, the condition of our bargain is not fulfilled, by my pleading a cause, and lofing it. The judges, thinking the arguments unanswerable on both sides, put off the cause to a long day."

[ocr errors]
[ocr errors]



Account of the remaining books of the Organon.


SECT. I. Of the Laft Analytics.

N the First Analytics, fyllogifms are confidered in respect of their form; they are now to be confidered in respect of their matter. The form lies in the neceffary connection between the premises and the conclufion; and where fuch a connection is wanting, they are faid to be informal, or vicious in point of form.

But where there is no fault in the form, there may be in the matter; that is, in the propofitions of which they are composed, which may be true or falfe, probable or improbable.

When the premifes are certain, and the conclufion drawn from them in due form, this is demonftration, and produces fciSuch fyllogifms are called apodic3 D 2



tical; and are handled in the two books of the Laft Analytics. When the premises are not certain, but probable only, fuch fyllogifms are called dialectical; and of them he treats in the eight books of the Topics. But there are fome fyllogifms which feem to be perfect both in matter and form, when they are not really fo: as, a face may feem beautiful which is but painted. Thefe being apt to deceive, and produce a falfe opinion, are called fophiftical; and they are the fubject of the book concerning Sophifms.

To return to the Laft Analytics, which treat of demonftration and of fcience: We fhall not pretend to abridge these books; for Ariftotle's writings do not admit of abridgement: no man in fewer words can fay what he fays; and he is not often guilty of repetition. We fhall only give fome of his capital conclufions, omitting his long reafonings and nice diftinctions, of which his genius was wonderfully productive.

All demonftration must be built upon principles already known; and these upon others of the fame kind; until we come

at laft to first principles, which neither


can be demonftrated, nor need to be, being evident of themselves.

We cannot demonftrate things in a circle, fupporting the conclufion by the premises, and the premises by the conclufion. Nor can there be an infinite number of middle terms between the first principle and the conclufion.

In all demonftration, the first principles, the conclufion, and all the intermediate propofitions, must be neceffary, general, and eternal truths: for of things fortuitous, contingent, or mutable, or of individual things, there is no demonstration.

Some demonftrations prove only, that the thing is thus affected; others prove, why it is thus affected. The former may be drawn from a remote cause, or from an effect: but the latter must be drawn from an immediate caufe; and are the most perfect.

The first figure is beft adapted to demonftration, because it affords conclufions univerfally affirmative; and this figure is commonly used by the mathematicians.

The demonftration of an affirmative propofition is preferable to that of a nega

« AnteriorContinuar »