— 663 —
Experiences and Testimonies clashing, infinitely vary the degrees of Probability.
      §9. Thus far the matter goes easie enough. Probability upon such
grounds carries so much evidence with it, that it naturally deter-
mines 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 is 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 Qualifi-
cations, Tempers, Designs, Over-sights, etc. of the Reporters,
that ’tis 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 Entertainment, as we call Belief, Con-
jecture, Guess, Doubt, Wavering, Distrust, Disbelief, etc.
Locke Hum IV, 16, §9, p. 663