414 LOGIC: OR, THE RIGHT USE OF REASON. Propositions according to their different degrees of evidence are .distinguished into certain and dubious.* Where the evidence of the agreement or disagreement of the ideas is so strong and plain, that we cannot forbid nor delay our assent; the proposition is called certain, as every circle bath a eentre, the world did not create itself. An assent to such proposi- tions is honoured with the name of knowledge. But when there is any obscurity upon the agreement or dis- agreement of the ideas, só that the mind does not clearly per- ceive it, and is not compelled to assent or dissent, then Lité tiro- position, in a proper and philosophical sense, is called doubtful or uncertain ; as, " the planets are inhabited ; the souls of brutes are there matter ; the world will not stand a thousand years lon- ger ; Dido built the city of Carthage," &c. Such uncertain propositions are called opinions. When we consider ourselves as philosophers, or searchers after truth, it would be well if we always suspended a full judge ment or determination about any thing, and made farther enqui- ries, where this plain and perfect evidence is wanting; but we are so prone of ourselves to judge without full evidence, and in some cases the necessity of action in the affairs of life, constrains us to judge and determine upon a tolerable degree of evidence, that we vulgarly call those propositions certain, where we have but very little room or reason to doubt of them, though the evi.r dente be not complete and resistless. Certainty, according to the schools, is distinguished into objective and subjective. Objective certainty, is when the propo . sition is certainly true in itself; and subjective, when we are certain of the truth of it. The one is in things, the other is in our minds. But let it be:observed here, that every proposition in itself is certainly true or certainlyfalse. For though doubtfulness or uncertainty seems to be a medium between certain truth and certain falsehood in our minds, yet there is no such medium in things themselves, no, not even in future events; for now at this time it is certain in itself, that 113idsummer -day seven years hence will be serene, or it is certain it will be cloudy, though we are uncertain and utterly ignorant what sort of day it will be; this certainty of distant futurities is known to God only.. Uncertain or dubious propositions, that is, opinions, are distinguished into probable, or improbable. ' It may be objected, that this certainty and uncertainty being only in the mind,'the division belongs'to propositions rather according to the degrees of our assent, than the degrees of evidence. But it may well lie answered, that the evidence here intended is that which appears so to the miad, and not she were evi- deuce in the nature of things, besides, (as we shall shew immediately) the degree of assent ought to be exactly proportionable to the degree of evidence; and therefore the differeoce is not great, whether propositions be called certain or tau - certain, according to the measure of evidence, or of assent..
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