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berlefs claffes of beings rifing one above another by differences fcarce perceptible, and leaving no where a fingle 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 fpecies. The argument here from analogy carries great weight, because we entertain no 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 space of the earth covered with "water fo large as the Terra Australis in
cognita, we may reasonably infer, that
"fo great a part of the earth is not altogether fea, but that there must be some proportion of land." The uniformity of nature with respect to the intermixture of sea and land, is an argument that affords but a very flender degree of conviction; and from late voyages it is discovered, that the argument holds not in fact. The following argument of the fame kind, tho' it cannot be much rely'd on, seems however better founded. The inhabit
ants of the northern hemisphere, have, "in arts and sciences, excelled fuch of the "fouthern as we have any knowledge of: ·
and therefore among the latter we ought not to expect many arts, nor much cul❝tivation."
After a fatiguing investigation of numberless 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 discovering truth and acquiring knowledge, viz. intuition and reafoning. By intuition we discover fubjects and their attributes, paffions, internal action, and in short every thing that is matter of fact. By intuition E e 2
we also discover feveral relations. There are fome facts and many relations, that cannot be discovered by a fingle act of intuition, but require feveral fuch acts linked together in a chain of reafoning.
Knowledge acquired by intuition, includes for the most part certainty: in fome instances it includes probability only. Knowledge acquired by reasoning, 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 facs. Where 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 fubject: mathematical reafoning is of that kind; and perhaps the only inftance. The fecond is, where the conclufion is derived from fome propofition, of which we are certain by intuition.
Probable reasoning is endless in its va rieties; and affords different degrees of conviction, depending on the nature of the subject upon which it is employ'd,
Progrefs of Reason.
A Progrefs from infancy to maturity in
the mind of man, fimilar to that in his body, has been often mentioned. The external fenfes, being early neceffary for felf-prefervation, arrive quickly at maturity. The internal fenfes are of a flower growth, as well as every other mental power: their maturity would be of little or no ufe while the body is weak, and unfit for action. Reafoning, as obferved in the first fection, requires two mental powers, the power of invention, and that of perceiving relations. By the former are discovered intermediate propositions, having the fame relation to the funda mental propofition and to the conclufion
and that relation is verified by the latter. Both powers are neceffary to the perfon who frames an argument, or a chain of reafoning the latter only, to the perfon who judges of it. deficient in both.
Savages are miserably
With respect to the former, a favage may have from his nature a talent for invention; but it will ftand him in little ftead without a stock of ideas enabling him to felect what may anfwer his purpofe; and a favage has no opportunity to acquire fuch a stock. With refpect to the latter, he knows little of relations. And how fhould he know, when both study and practice are neceffary for diftinguishing between relations? The understanding, at the fame time, is among the illiterate obfequious to paffion and prepoffeffion; and among them the imagination acts without control, forming conclufions often no better than mere dreams. In fhort, confidering the many causes that mislead from just reasoning, in days especially of ignorance, the erroneous and abfurd opinions that have prevailed in the world, and that continue in fome measure to prevail, are far from being furprifing. Were reafon our only