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dent axioms; as that the whole is greater than a part, or, every effect is produced by some cause.
The evidence of reason, founded on clear and indubitable deductions from well-founded premises and doctrines.
And the evidence of faith, deduced from the testimony of others.
406. Demonstrations are a succession of connected Propositions, beginning with self-evident truths and advancing to remoter ones.
A Demonstration á priori, is when the effect is proved by referring to the cause.
A Demonstration a posteriori, is when the cause is inferred from the effects.
Obs.—Corollaries are self-evident inferences from established propositions.
407. Sophistry is false reasoning, founded on false premises, or on ambiguity of terms.
Obs.—As most of the evils which exist in society grow out of sophistry, no art is more important than that which enables us to detect or expose it. The crimes of courts and wicked ministers usually escape punishment, from the effect of sophistry ; and there would be few or no wars, if sophistry did not triumph in the statements of the parties.
A Sophism of composition, is when we infer that of any thing in an aggregate or compounded sense, which is true only in a divided sense.
A Sophism of division, is when we infer any thing in a divided sense, which is true only in a compounded sense.
A Sophison of equivocation, is when we use words of an ambiguous or double sense, and draw inferences in one sense, of which the proposition is capable only in the other.
408. A petitio principii, or begging the
question, is the supposition of what is not granted, or a supposed proof, by stating the question in other words.
The reductio ad absurdum, is when the truth of a proposition is proved by shewing the absurdity of a contrary supposition.
409. Induction consists in distributing a general idea into its species, and ascribing to the whole the property found in the species.
A false induction is when general deductions are made from too limited a number of experiments or facts.
The fallacia accidentis, is when we draw inferences in regard to the nature of a thing, from cir" cumstances only temporary or accidental.
The ignorantia elenchi, is a mistake of the question, or when one thing is proved instead of another.
Analogy is an argument in which, from corresponding causes, are deduced corresponding effects.
Obs.The sources of errors are, (1.) The want of diligence in investigation. (2.) Judging of things by their external appearances only. (3.) Not separating the good and bad qnalities that pervade the same thing, but forming a hasty judgment. (4.) Comparing things with our own situation in life; or as they happen to affect us. (5.) Associating an idea with something disagreeable, or the contrary. (6.) Prejudices formed in our infancy. (7.) Giving credit to the assertions or misrepresentations of others, without enquiring into their motives, as in news-writers and reviewers; and (8.) Submitting to the force and influence of custom and fashion.
410. A Syllogism is a sentence made up of three propositions, so disposed, as that the last is necessarily inferred from those that precede it.
Every syllogismi contains two premises and a
conclusion; or a major and minor proposition and a consequence.
Example of a Syllogism: Major. - - Our Creator ought to be worshipped. Minor. . . God is our creator; Consequence. Therefore God ought to be worshipped.
411. An Argument is a series of syllogisms; and, although arguments do not retain their syllogistic form in ordinary discourse, yet all arguments may be reduced to syllogisms; and errors or sophisms may thus be detected,
412. Formerly, Logic, or the art of reasoning, was almost the sole business of a university-education ; but it is now in some degree superseded, by the practice of reasoning in the study of mathematics, by the various branches of philosophy, and by the perusal of the classic authors.
Obs.—The great master of philosophy, A RISTOTLE, di. vided all science into THEOREMs formed of SYLLOGISMS, which Syllogisms were composed of PROPOSITIONS, which Propositions were formed of TERMS; which Terms were WORDS or Signs of our IDEAS of Things. He then considered all Things with reference to their TEN CATEGORIES, or Predicaments; as Substance, Quality, Quantity, Relation, Action, Passiveness, When, Where, Position, and Habit.
XVII. Rhetoric. 413. Rhetoric teaches us to affect the passions by suitable illustrations and imagery; and to arrange our arguments to the best advantage, so as to make the deepest impression on the feelings and judgment of those we address.
414. The following are the chief figures of speech.
a. Simile, or comparison, is that figure by
which we compare one thing with another for the sake of illustration.
b. Metaphor, is a comparison expressed without the signs of comparison; as, when we say
of a minister, that he is the pillar of the state, we speak in metaphor; and when we say, that Charles the twelfth was the lion of the north, we speak metaphorically.
c. Allegory, is a continuation of several metaphors, so connected as to form a kind of parable or fable; as, in describing the people of Israel under the image of a vine.
d. Irony, is a figure in which we urge one thing, and mean the contrary, in order to give effect to our meaning; as, in describing a notorious cheat, we say, ironically, A mighty honest man, truly!
e. Hyperbole, gives us the highest idea of an object, and magnifies it beyond its natural dimensions; as, Achilles was swifter than a stag:
f. Antithesis, is the contrast or opposition of two objects in a sentence; as, If you seek to make a man rich, study not so much to increase his stores, as to diminish his desires.
g. Climax, or Gradation, is a figure by which we rise from one circumstance to another, till our idea is raised to the highest.
h. Personification, is a figure by which we attribute life and the use of reason to inanimate objects and irrational creatures.
i. Apostrophe, is a figure by which we address absent persons, or inanimate objects which we personify.
k. Interrogation, is a figure which, by asking a
question, gives ardour and energy to our dis
l. Exclamation, is a figure that expresses some strong emotion of the mind, and is generally followed by a note of admiration.
415. Rhetorical disposition or arrangement is the placing of the arguments, or the parts of a discourse, oration, or composition, in the most suitable and impressive order.
The parts of a discourse are sometimes five, and sometimes six; viz. the Exordium, the Narration, the Proposition, the Confirmation, the Refutation, and the Peroration.
a. In the Exordium, or beginning of a discourse, the writer or speaker gives some intiination of his subject, and solicits favour and attention.
b. The Narration is a brief recital of the facts connected with the case from the beginning to the end.
c. In the Proposition, is given the true state of the question; specifying the points maintained, and those in which the writer or speaker differs from the adversary.
d. The Confirmation assembles all the proofs and arguments which can be adduced.
e. In the Refutation, the writer or speaker answers the arguments and objections of his opponent.
f. In the Peroration, he sums up the strong and principal arguments, and endeavours to excite the passions in his favour.
416. À distinct and audible delivery is essential to a good orator.