(2.) _The four Aristotelian principles or causes, and the relation of form and matter._—From the criticism of the Platonic doctrine of ideas arose directly the groundwork of the Aristotelian system, the determinations of matter (ὕλη), and form (εἶδος). Aristotle enumerates four metaphysical principles or causes: matter, form, moving cause, and end. In a house, for instance, the matter is the wood, the form is the conception of the house, the moving cause is the builder, and the end is the actual house. These four determinations of all being resolve themselves upon a closer scrutiny into the fundamental antithesis of matter and form. The conception of the moving cause is involved with the two other ideal principles of form and of end. The moving cause is that which has secured the transition of the incomplete actuality or potentiality to the complete actuality, or induces the becoming of matter to form. But in every movement of the incomplete to the complete, the latter antedates in conception this movement, and is its motive. The moving cause of matter is therefore form. So is man the moving and producing cause of man; the form of the statue in the understanding of the artist is the cause of the movement by which the statue is produced; health must be in the thought of the physician before it can become the moving cause of convalescence; so in a certain degree is medicine, health, and the art of building the form of the house. But in the same way, the moving or first cause is also identical with the final cause or end, for the end is the motive for all becoming and movement. The moving cause of the house is the builder, but the moving cause of the builder is the end to be attained, _i. e._ the house. From such examples as these it is seen that the determinations of form and end may be considered under one, in so far as both are united in the conception of actuality (ἐνέργεια), for the end of every thing is its completed being, its conception or its form, the bringing out into complete actuality that which was potentially contained in it. The end of the hand is its conception, the end of the seed is the tree, which is at the same time the essence of the seed. The only fundamental determinations, therefore, which cannot be wholly resolved into each other, are matter and form.