Logic, Metaphysics, and the Natural Sociability of Mankind. Francis Hutcheson

and evident axioms are to be posited.”

      3. “One must proceed from the better known to the less known by demonstrations step by step,” and premisses which go beyond axioms and propositions previously demonstrated are not to be admitted.

      Demonstrations only deal with abstract propositions, especially in geometry and arithmetic.

      There is no single principle of human knowledge which you may rightly say is prior to the rest. There are many evident principles apart from the most general axioms. Nor will any syllogism carry full credence unless both terms of the conclusion are found connected with the middle term in evident propositions. In demonstration, therefore, through several syllogisms which are connected in a continuous series, the number of evident propositions will exceed the number of middle terms by one.

      In absolute propositions, and in those which are chiefly useful in life, there is another way of knowing which has its own proper evidence, albeit different from demonstrative [evidence]. Absolute propositions asserting that things exist are known (1) by consciousness, (2) by sense, (3) by reasoning, or by an observed link with existing things, or (4) by testimony. Other experiential truths about the powers and qualities of things are chiefly learned by experience, and by a varied acquaintance with life, and by induction; and whenever any example is similar, it should, other things being equal, be included with the larger rather than the smaller number. For rarely can men see any connection among the actual powers and qualities of things.

      There are innumerable degrees of likelihood, from the slightest probability to full and stable assent; from the judicious appreciation [of their degrees] grave men are more likely to earn a reputation for prudence and wisdom than from cleverness in the sciences.

      “Assent given to arguments which are probable but do not achieve the highest likelihood” is called opinion. Where either of the premisses is uncertain, there is only a probable conclusion; hence in a long chain of arguments, the result will be a very weak assent.

      Arguments which create belief are either artificial and involve the use of reasoning, or inartificial, from testimony. “In recent [writers]¹⁶ assent resting on testimony is belief (par excellence).” Belief is either divine or human, depending on whether the assent rests on the testimony of God or of men.

      Divine belief will be a fully firm assent when it is clearly established that God has revealed something, since a superior nature cannot deceive or be deceived.

      Human belief too, although often hazardous, may sometimes attain full certainty, when it is clear that the witnesses could not have been deceived, and could not have intended to deceive others, so that neither their knowledge nor their reliability nor their truthfulness is in doubt.

      Sometimes the knowledge of witnesses will be evident from the nature of the matter in hand; and their reliability will be established if they have not been induced to give testimony about the question in hand by any reward or other inducements; even more so when they testify to their own peril or loss, and could not expect to persuade others, if they themselves knew that the thing was otherwise.

      If testimony is not liable to any suspicion of fraud or ignorance, belief may be given (1) to facts which cannot be known in any other way; (2) also to things totally different from what we have previously observed, if indeed there are no internal arguments that prevent belief; (3) and third, even to things that are strange and contrary to all our experience or observation, provided the testimony deals with material and circumstances that are different and remote from our own affairs.