Abstract

Descartes's general rule that “whatever is clearly and distinctly perceived is true” has traditionally been criticized on two closely related grounds. As Leibniz, for example, puts it, clearness and distinctness are of no value as criteria of truth unless we have criteria of clearness and distinctness; but Descartes gives none. And consequently, the standards of judgment which the rule in fact evokes are purely subjective and psychological. There must hence be set up analytic, logical “marks” by means of which it can infallibly and without arbitrariness be recognized whether any ideas or propositions are or are not clear and distinct