All affirmative judgments are based on the principle of Identity. A subject is identical to its predicate. All negative judgments have the principle of Contradiction as their foundation. A subject is opposed to its predicate. Judgments in which identity or contradiction is mediately known, by means of intermediate predicates and by means of the analysis of concepts, are provable. Judgments in which identity or contradiction is immediately known cannot be proved (See Section II). These unprovable judgments precede definitions because we must recognize a subject's predicate before we can define the subject.