ARISTOTELIANISM. Aristotle is the first philosophical writer to make a strict sep aration of the branches of philosophy. His writings, in terms of their subject matter, fall into the following groups: Logic, Metaphysics, Physics, Ethics, Politics and the Philosophy of Art. A classification made by Aristotle, but not applied to the arrangement of his writ ings, is: (1) theoretic philosophy; (2) philos ophy of conduct; (3) philosophy of production, that is, of art. The analysis of the problems and subject matter of philosophy and science begins with him. In Plato's writings the vari ous problems are fused together and treated integrally and synthetically in an ethico-meta physical system.
Logic. —For Aristotle logic is a methodol ogy of science, a propxdeutic to the other dis ciplines. It is not strictly a science, because science has some essence or aspect of reality for its subject matter, while logic is concerned with the forms of knowing. Formal logic was founded by Aristotle and almost completely de veloped by him. Its chief feature is the doc trine of the syllogism, the process of reaching scientific or apodictic conclusions. The syllo gistic process is a deductive process, that is, it derives particular conclusions from general principles or accepted premises. The possibil ity of deriving such conclusions rests upon the axiomatic principles of contradiction and the excluded middle, that is, two contradictories cannot at the same time and in the same ref erence be true; and of two contradictory prop ositions, one must be true and the other false, and a third intermediate proposition is ex cluded. The logical treatises were grouped to gether by Aristotle's successors and called the Organon or instrument of science. The sev eral treatises consist of the Categories, the Hermeneutics, the Analytics and the Topics. The Categories discuss simple terms; the Hermeneutics discuss the combination of terms with a predicate, that is, the judgment or prop osition; and the Analytics and Topics discuss the combination of propositions in the syllo gism. The syllogistic conclusion is the deriva
tion of one judgment from another by means of a middle term. The notion, judgment and con clusion are the three elements with which formal logic operates. The categories, or gen eral notions under which reality is viewed, are enumerated by Aristotle as substance; quantity, quality, relation, place, time, position, posses sion, action, passion. These ten categories are evidently not derived from any single prin ciple and are neither exhaustive nor mutually exclusive. Aristotle's main interest is in the syllogism; simple terms or notions and the judgment are scantily treated. His treatment of the syllogism is practically exhaustive. Mod ern logic has supplemented his work by add ing to his theory of the categorical conclusion, which was his chief interest, the theory of hy pothetical and disjunctive conclusions; further, by adding a fourth figure to his three, and lastly by developing the theory of inductive logic and the method of the sciences. Aristotle regards deductive logic as the only method that can furnish demonstration or apodictic con clusions. Science, however, would not be pos sible with syllogistic demonstration alone, for if all our premises had to be proved we should be forced into an endless regress. Therefore, science must accept certain fundamental prin ciples as its axiomatic postulates. From these accepted postulates scientific proof proceeds by deduction. In addition to this Aristotle men tions the further method of induction without elaborating it, saying, however, that universal principles are secured by it from particular in stances and that it has the advantage over de duction by being nearer to our sense experience and therefore more generally intelligible. On the other hand, he insists that a complete knowledge of particulars is necessary to a com pletely certain induction, and this, owing to the multiplicity of particulars, being rarely pos sible, induction lacks in its conclusions the co gency of the deductive syllogism.