included in itself a metaphysic like the Epicurean, establishing one kind and one only of active material substance. For similar or analogous reasons Vico rejected the philosophies of Gassendi, Spinoza and Locke; and the physical science of other authors such as Robert Boyle seemed to him valuable for purposes of medicine and the "spargiric art," but useless for philosophy. Galileo he considered to have looked at physical science with the eye of a great geometrician, but without the aid of the full light of metaphysics. He had sympathy with philosophers who were also geometricians, and therefore with the Pythagorean or Timaean physics, according to which the world consists of numbers; with the Platonic metaphysics, which from the form of our minds without any other hypothesis establishes, upon our knowledge and consciousness of certain eternal truths which are in our mind and cannot be ignored or denied, the eternal idea as the principle of all things; with the doctrine of metaphysical points, attributed by him to Zeno the Stoic; and finally with the philosophy of the Italian Renaissance, the period adorned by Ficino, Pico della Mirandola, Steuco, Nifo, Mazzoni, Piccolomini, Acquaviva and Patrizio. The fundamental concept of his cosmology was supplied by the metaphysical point, in which the employment of mathematics in metaphysics, a process admitted by Vico as analogous to that of construction, found expression. Just as from the geometrical point proceed the line and the surface, and the point which is defined as having no parts supplies the proof that lines otherwise incommensurable can be divided equally into their component points, so it is legitimate to postulate points not geometrical but metaphysical, which though not extended generate extension. Between God, who is rest, and matter, which is motion, the intermediate place is taken by the metaphysical point, whose attribute is conation, the indefinite energy and attempt on the part of the universe to bring into being and sustain each particular thing. The existence of matter is nothing but an indefinite power of keeping the universe extended, which underlies all extended objects equally however unequal they may be, and also an indefinite power of motion underlying all particular motions, however unequal. Behind a grain of sand lies something which when this particle is divided gives to it and preserves in it an infinite extension and magnitude; so that the whole mass of the universe is included in the grain of sand, if not actually, yet potentially and in capacity. This effort of the universe, underlying each smallest particle of matter, is neither the extension of the particle nor the extension of the universe: it is the thought of God, which, free from all materiality, gives motion and impulse to the whole. Every particular determination of reality agrees with this fundamental truth. Time is divisible, eternity indivisible; disturbances of the mind wax and wane, its