ATOMS. The atomic theory of the universe was originated by Democritus, the Greek philosopher, who wus born at Abdera in Thrace about 460 B.C. Demo critus was a disciple of Leucippus, whose teaching he developed. " According to this theory there are in the universe two fundamental principles, the Full and the Void. The Full is formed by the atoms, which are primitive bodies of like quality but different form, in numerable, indivisible, indestructible. Falling for ever through the infinite void, the large and heavier atoms overtake and strike upon the smaller ones, and the oblique and circular motions thence arising are the be ginning of the formation of the world. The difference of things arises from the fact that atoms differ in number, size, form and arrangement. The soul consists of smooth round atoms resembling those of fire; these are the nimblest, and in their motion, penetrating the whole body, produce the phenomena of life. The im pressions on the senses arise from the effect produced in our senses by the fine atoms which detach themselves from the surface of things. Change is in all cases
nothing but the union or separation of atoms " (0. Sey ffert, Diet., s.v. "Democritus "). Epicurus (b. ?,42 B.C.) accepted the atomic theory, but in his teaching it as sumed, in several respects, a different form. He gave it a more ethical and religious bearing. " It seemed to him to be most consonant with the theory of pleasure as the Sun mum bonum, which was the ruling feature in Epicurus' philosophy, and it struck at the root of religious superstition by excluding the gods from ar bitrary and capricious interference with the government of the world " (W. L. Davidson, The Stoic Creed, 1907). According to Epicurus, however, the soul is composed of no less than four elements—heat, air, vapour, and another unnamed; and while Democritns found no place for free will. Epicurus regarded it as a fact of ex perience, and attached great importance to it as a fundamental principle in ethics.