Ch. 26
What is the test of error.
Every error implies a contradiction; for since
he who errs does not wish to err, but to be in
the right, it is evident that he acts contrary to his
wish. What does a thief desire to attain? His own
interest. If, then, thieving be really against his interest, he acts contrary to his own desire. Now, every
rational soul is naturally averse to self-contradiction;
but so long as any one is ignorant that it is a contradiction, nothing restrains him from acting contradictorily; but whenever he discovers it, he must as
necessarily renounce and avoid it, as any one must
dissent from a falsehood whenever he perceives it to
be a falsehood; only while this does not appear, he
assents to it as to a truth.
He, then, is gifted in speech, and excels at once in
exhortation and conviction, who can disclose to each
man the contradiction by which he errs, and prove
clearly to him that what he would he doth not, and
what he would not, that he doth. For, if that be
shown, he will depart from it of his own accord; but,
till you have shown it, be not surprised that he remains where he is; for he proceeds on the semblance
of acting rightly. Hence Socrates, relying on this fac-
ulty, used to say. "It is not my custom to cite any
other witness for my assertions; but I am always
contented with my opponent. I call and summon
him for my witness; and his single evidence serves
instead of all others." For he knew that if a rational soul be moved by anything, the scale must
turn whether it will or no. Show the governing faculty of Reason a contradiction, and it will renounce
it; but till you have shown it, rather blame yourself
than him who remains unconvinced.