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evidence of perfons above all exception. Sometimes it finks to the loweft degree of probability, as when a fact is told by one who has no great reputation for truth, The nature of the fact, common or uncommon, has likewife an influence; an ordinary incident gains credit upon very flight evidence; but it requires the ftrongest evidence to overcome the improbability of an event that deviates from the ordinary courfe of nature. At the fame time, it must be obferved, that belief is not always, founded upon rational principles. There are biaffes and weakneffes in human nature that fometimes difturb the operation, and produce belief without fufficient or proper evidence: we are difpofed to believe on very flight evidence, an interefting event, howeyer rare or fingular, that alarms and agitates the mind; because the mind, in agitation, is remarkably fufceptible of impreffions: for which reafon, ftories of ghofts and apparitions pafs current with the vulgar. Eloquence alfo has great power over the mind; and, by making deep impreffions, enforces the belief of facts upon evidence that would not be regarded in a cool moment.

The dependence that our perception of real existence, and confequently belief, hath upon oral evidence, enlivens focial intercourfe, and promotes fociety. But the perception of real existence has a still more extenfive influence; for from that perception is derived a great part of the entertainment we find in history, and in historical fables (a). At the fame time, a perception that may be raised by fiction as well as by truth, would often miflead, were we abandoned to its impulfe; but the God of nature hath provided a remedy for that evil, by erecting within the mind a tribunal, to which there lies an appeal from the rafh impreffions of fenfe. When the delufion of eloquence or of dread

(a) Elements of Criticism, cb. 2. part 1. §7,

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fubfides,

fubfides, the perplexed mind is uncertain what to believe. A regular procefs commences, counfel is heard, evidence produced, and a final judgement pronounced, fometimes confirming, fometimes varying, the belief impressed upon us by the lively perception of reality. Thus, by a wife appointment of nature, intuitive belief is fubjected to rational difcuffion: when confirmed by reason, it turns more vigorous and authoritative: when contradicted by reafon, it disappears among fenfible people. In fome inftances, it is too headstrong for reafon; as in the cafe of hobgoblins and apparitions, which pass current among the vulgar in spite of reafon.

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We proceed to the other kind of belief, viz. that which is founded on reafoning, to which, when intuition fails us, we must have recourfe for ascertaining certain facts. Thus, from known effects, we infer the existence of unknown caufes. That an effect must have a cause, is an intuitive propofition; but to ascertain what particular thing is the cause, requires commonly a process of reafoning. This is one of the means by which the Deity, the primary caufe, is made known to us, as mentioned above. Reafon, in tracing caufes from known effects, produces different degrees of conviction. It fometimes produces certainty, as in proving the exiftence of the Deity; which on that account is handled above, under the head of knowledge. For the most part it produces belief only, which, according to the ftrength of the reafoning, fometimes approaches to certainty, and fometimes is fo weak as barely to turn the fcale on the fide of probability. Take the following examples of different degrees of belief founded on probable reafoning: When Inigo Jones flourished, and, was the only architect of note in England, let it be fuppofed that his model of the palace of Whitehall had been presented to a stranger, without mentioning the author. The stranger, in the first place, would have been intuitively certain, that this was the work of

fome

fome being intelligent and fkilful. Secondly, He would have had a conviction approaching to certainty, that the operator was a man. And, thirdly, He would have had a conviction that the man was Inigo Jones; but lefs firm than the former. Let us next suppose another English architect little inferior in reputation to Jones: the stranger would, still have pronounced in favour of the latter; but his belief would have been in the lowest degree.

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When we investigate the causes of certain effects, the reafoning is often founded upon the known nature of man. In the high country, for example, between Edinburgh and Glafgow, the people lay their coals at the end of their houses, without any fence to fecure them from theft: whence it is, rationally inferred, that coals are there in plenty, In the weft of Scotland, the corn→ stacks are covered with great care and nicety: whence it is inferred, that the climate is rainy. Placentia is the capital town of Biscay; and the only town in Newfoundland bears the fame name; from which circumstance it is conjectured, that the Bifcayners were the first Europeans who made a fettlement in that island.

Analogical reafoning, founded upon the uniformity of nature, is frequently employ'd in the investigation of facts; and we infer, that facts of which we are uncertain, must resemble thofe of the fame kind that are known. The bulk of the reafonings in natural philofophy are of that kind. Take the following examples. We learn from experience, that proceeding from the humbleft vegetable to man, there are numberlefs claffes of beings rifing one above another, by differences fearca perceptible, and leaving no where a single gap or interval; and from conviction of the uniformity of nature, we infer, that the line is not broken off here, but is carried on in other worlds, till it end in the Deity. I proceed to another example. Every man is confcious of a felf-motive power in himself; and from the uniformity of nature, we

infer the fame power in every one of our own species. The argument here from analogy carries great weight, because we entertain nọ doubt of the uniformity of nature with refpect to beings of our own kind. We apply the fame argument to other animals, tho'their resemblance to man appears not fo certain, as that of one man to another. But why not alfo apply the fame argument to infer a felf-motive power in matter? When we fee matter in motion without an external mover, we naturally infer, that, like us, it moves itself. Another example is borrow'd from Maupertuis. "As there is no known fpace of the earth covered with water fo large as the Terra Auftralis incognita, we may reasonແ ably infer, that fo great a part of the earth is not altogether sea, but that there must be fome proportion of land." The uniformity of nature with respect to the intermixture of fea and land, is an argument that affords but a very flender degree of conviction. The following argument of the fame kind, tho' it cannot be much rely'd on, feems however better founded. The "inhabitants of the northern hemifphere, have, in arts and fciences, excelled fuch of the fouthern as we have any knowledge of: "and therefore, if inhabitants be found in the Terra Australis incognita, we ought not to expect among them many arts, nor "much cultivation."

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After a fatiguing investigation of numberlefs particulars which divide and scatter the thought, it may not be unpleasant to bring all under one view by a fuccinct recapitulation.

We have two means for difcovering truth, and acquiring knowledge, viz. intuition and reafoning. By intuition we difcover fubjects, and their attributes, paffions, internal action, and in fhort every thing that is matter of fact. By intuition we also difcover feveral relations. There are fome facts, and many relations, that cannot be difcovered by a fingle act of intuition,

but

but require feveral fuch acts linked together in a chain of reason

ing.

Knowledge acquired by intuition, includes for the most part certainty in fome inftances it includes probability only. Knowledge acquired by reafoning, frequently includes certainty; but more frequently includes probability only.

Probable knowledge, whether founded on intuition or on reafoning, is termed opinion when it concerns relations; and is termed belief when it concerns facts. When knowledge includes certainty, it retains its proper name.

Reafoning that produces certainty, is termed demonftrative; and is termed probable, when it only produces probability.

Demonstrative reafoning is of two kinds. The firft is, where the conclufion is derived from the nature and inherent properties of the subject: mathematical reasoning is of that kind; and perhaps the only inftance. The second is, where the conclufion is derived from fome propofition, of which we are certain by intuition.

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Probable reasoning is endlefs in its varieties; and affords different degrees of conviction, depending on the nature of the fubject upon which it is employ'd,

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