An Essay Concerning Humane Understanding, Volume 2: MDCXC, Based on the 2nd Edition, Books 3 and 4
John Locke · en
But yet there is some end of it; and a man having carefully inquired
into all the grounds of probability and unlikeliness; done his utmost to
inform himself in all particulars fairly, and cast up the sum total on
both sides; may, in most cases, come to acknowledge, upon the whole
matter, on which side the probability rests: wherein some proofs in
matter of reason, being suppositions upon universal experience, are so
cogent and clear, and some testimonies in matter of fact so universal,
that he cannot refuse his assent. So that I think we may conclude, that,
in propositions, where though the proofs in view are of most moment, yet
there are sufficient grounds to suspect that there is either fallacy in
words, or certain proofs as considerable to be produced on the contrary
side; there assent, suspense, or dissent, are often voluntary actions.
But where the proofs are such as make it highly probable, and there is
not sufficient ground to suspect that there is either fallacy of words
(which sober and serious consideration may discover) nor equally valid
proofs yet undiscovered, latent on the other side (which also the nature
of the thing may, in some cases, make plain to a considerate man;)
there, I think, a man who has weighed them can scarce refuse his assent
to the side on which the greater probability appears. Whether it be
probable that a promiscuous jumble of printing letters should often
fall into a method and order, which should stamp on paper a coherent
discourse; or that a blind fortuitous concourse of atoms, not guided by
an understanding agent, should frequently constitute the bodies of any
species of animals: in these and the like cases, I think, nobody that
considers them can be one jot at a stand which side to take, nor at all
waver in his assent. Lastly, when there can be no supposition (the thing
in its own nature indifferent, and wholly depending upon the testimony
of witnesses) that there is as fair testimony against, as for the matter
of fact attested; which by inquiry is to be learned, v.g. whether there
was one thousand seven hundred years ago such a man at Rome as Julius
Caesar: in all such cases, I say, I think it is not in any rational
man's power to refuse his assent; but that it necessarily follows, and
closes with such probabilities. In other less clear cases, I think it is
in man's power to suspend his assent; and perhaps content himself with
the proofs he has, if they favour the opinion that suits with his
inclination or interest, and so stop from further search. But that a
man should afford his assent to that side on which the less probability
appears to him, seems to me utterly impracticable, and as impossible
as it is to believe the same thing probable and improbable at the same
time.
16. Where it is in our Power to suspend our Judgment.