9. Experience and testimonies clashing infinitely vary the degrees of probability.
Thus far the matter goes easy
enough. Probability upon such grounds carries so much evidence with it, that it naturally determines the
judgment, and leaves us as little liberty to believe or disbelieve, as a demonstration does, whether we will know,
or be ignorant. The difficulty is, when testimonies contradict common experience, and the reports of history and
witnesses clash with the ordinary course of nature, or with one another; there it is, where diligence, attention, and
exactness are required, to form a right judgment, and to proportion the assent to the different evidence and
probability of the thing: which rises and falls, according as those two foundations of credibility, viz., common
observation in like cases, and particular testimonies in that particular instance, favour or contradict it. These are
liable to so great variety of contrary observations, circumstances, reports, different qualifications, tempers,
designs, oversights, etc., of the reporters, that it is impossible to reduce to precise rules the various degrees
wherein men give their assent. This only may be said in general, That as the arguments and proofs pro and con,
upon due examination, nicely weighing every particular circumstance, shall to any one appear, upon the whole
matter, in a greater or less degree to preponderate on either side; so they are fitted to produce in the mind such
different entertainments, as we call belief, conjecture, guess, doubt, wavering, distrust, disbelief, etc.
