Doubting without a basis is the equivalent of—is indeed a form of—asserting
without a basis. Both procedures, being arbitrary, are disqualified by the very
nature of human cognition. In reason, certainty must precede doubt, just as a
grasp of truth must precede the detection of error. To establish a claim to
knowledge, what one must do is to prove an idea positively, on the basis of the
full context of evidence available; i.e., a man must prove that he is right. It
is not incumbent on anyone—nor is it possible—to prove that he is not
wrong, when no evidence of error has been offered.