III. LOGIC AND METAPHYSICS. 1. CONCEPTION AND RELATION OF THE TWO.—The word metaphysics was first furnished by the Aristotelian commentators. Plato had used the term dialectics, and Aristotle had characterized the same thing as “first philosophy,” while he calls physics the “second philosophy.” The relation of this first philosophy to the other sciences Aristotle determines in the following way. Every science, he says, must have for investigation a determined province and separate form of being, but none of these sciences reaches the conception of being itself. Hence there is needed a science which should investigate that which the other sciences take up hypothetically, or through experience. This is done by the first philosophy which has to do with being as such, while the other sciences relate only to determined and concrete being. The metaphysics, which is this science of being and its primitive grounds, is the _first_ philosophy, since it is presupposed by every other discipline. Thus, says Aristotle, if there were only a physical substance, then would physics be the first and the only philosophy, but if there be an immaterial and unmoved essence which is the ground of all being, then must there also be an antecedent, and because it is antecedent, a universal philosophy. The first ground of all being is God, whence Aristotle occasionally gives to the first philosophy the name of theology. It is difficult to determine the relation between this first philosophy as the science of the ultimate ground of things, and that science which is ordinarily termed the logic of Aristotle, and which is exhibited in the writings bearing the name of the _Organon_. Aristotle himself has not accurately examined the relations of these two sciences, the reason of which is doubtless to be found in the incomplete form of the metaphysics. But since he has embraced them both under the same name of logic, since the investigation of the essence of things (VII. 17), and the doctrine of ideas (XIII. 5), are expressly called logical, since he repeatedly attempts in the Metaphysics (_Book_ IV.), to establish the logical principle of contradiction as an absolute presupposition for all thinking and speaking and philosophizing, and employs the method of argument belonging to that science which has to do with the essence of things (III. 2. IV. 3), and since, in fine, the categories to which he had already dedicated a separate book in the Organon are also discussed again in the Metaphysics (_Book_ V.), it follows that this much at least may be affirmed with certainty, that he would not absolutely separate the investigations of the Organon from those of the Metaphysics, and that he would not counsel the ordinary division of formal logic and metaphysics, although he has omitted to show more clearly their inner connection.