1911 Encyclopædia Britannica/Predication
PREDICATION (from Lat. praedicare, to state, assert), in logic, the term which denotes the joining of a predicate to a subject in a judgment or proposition. The statement "all men are mortal" is to predicate mortality of all men. In other words a judgment is made up of a subject and a, predicate joined by a copula. Since the true unit of thought is the judgment, since all concepts or universals exist only in continuous thinking (judging), the theory of predication is a fundamental part of logic. The true relation of subject and predicate has not been determined with unanimity, various logicians emphasizing different aspects of the process (see Logic). The logical use of "predicate" is to be distinguished from the grammatical, which includes the verb, whether it be the verb "to be" in its various forms, or another verb. The simple grammatical sentence "he strokes the dog" the first word is the subject, while "strokes the dog" is the predicate, including verb and object. In logic every proposition is reducible to the form "A is B," "B" being the predicate. Thus the logical form of "he strokes the dog" would be "he is stroking the dog" or some other periphrasis which liberates and determines the logical predicate. The true significance of the logical copula is difficult. It cannot be described simply as a third (i.e. separate part) of the judgment, because until two terms are enjoined by it they are not subject and predicate. Much discussion has raged round the question whether the use of the verb "to be" as the copula implies that existence is predicated by the subject. It may be taken as generally agreed that this is not the case (see further Logic, and the textbooks).