§ 45.
1. In his physical theories, Epicurus is, in the main, at one with Democritus. He admits no transcendental Divine cause to account for the origin and dissolution of things. In Matter he finds the adequate cause of all things. Everything that comes into existence has its physical cause; there is no need of any higher agent to explain the phenomena of our experience. We may not, in each case, be able to assign the physical cause with complete certainty, but this is not a reason why we should recur to the notion of a higher Divine Cause. This side of the Epicurean theory is distinctly Atheistical.
2. Starting with the general principle that nothing is produced from nothing, and that no being of any kind can be reduced to nothing, Epicurus assumes as the primary principles of things vacuum and atoms. We must assume a vacuum, or space; for the bodies, of whose existence sensuous perception assures us, must have being and motion somewhere. Atoms, too, we must assume, since bodies are composite, and therefore divisible. Continuing the division of the composite mass, we must at last come to parts which are indivisible and unchangeable, unless things be said to be reducible to absolute nothing. These ultimate indivisible corpuscles are atoms (atoma). Space and atoms exist from eternity.
3. These atoms are of different dimensions, but they are all, alike, too minute to be visible. Size, form, and weight are their only attributes. Other qualities, such as heat, colour, &c., are produced by the union of the atoms. The number of these atoms is infinite. But how are bodies formed from these atoms? To this question Epicurus answers:
4. The atoms move in space, with a downward vertical movement, determined by their weight, all moving with the same velocity. In this movement a certain number of atoms deviate from the perpendicular line of descent. This deviation brings about collisions with the other atoms. These collisions sometimes lead to permanent combinations of the atoms, sometimes, by the rebound of the atoms from one another, they produce upward or lateral movements, which uniting to form rotatory motion, produce, in turn, new combinations of atoms. In this wise are formed bodies, which, it will be seen, are no more than complex arrangements of atoms.{1}
5. The aggregate of the bodies thus formed, united into a definite whole, constitute a world. The number of such worlds is infinite, for the number of atoms is without limit. The earth, and the stars visible from the earth, form one world. But an infinite number of other worlds also exist. These worlds are involved in a continuous process of formation and dissolution. But among the many worlds some are found which are possessed of life, and these endure for a longer time; the others pass quickly away.
6. The stars are not animated. Their real size is the same as their apparent: "for if their (real) magnitude were (apparently) diminished by distance, the same diminution should be effected in their brilliancy, which is, evidently, not the case. Animals and men are produced from the earth; man has been evolved, by successive stages, from a lower form."
7. The movement of the atoms, and the origin of the world thereby brought about, is, as has been said, a result of mere chance (Theory of Casualism). There is, therefore, in nature, neither final cause, nor any heimarmenê or Fate, resulting from a fixed necessity. Chance alone rules everything.
8. The existence of the gods is not to be denied; for we have a clear evidence of their existence in the fact that they frequently appear to men in dreams, and leave representative images of themselves (prolêpseis) behind in the mind. Moreover, since there are so many finite and mortal things in existence, the law of contraries requires that there should also exist beings which are eternal and blissful. Men are, however, in error when they picture to themselves the gods as supremely happy, and nevertheless assign to them the task of governing the world, and endow them with human feelings. These things are perfectly irreconcilable. It is only the ignorance which fails to find an explanation of natural phenomena in the forces and laws of nature itself which has recourse to the gods. The gods inhabit the spaces interposed between the stars, and lead there a happy life, not troubling themselves about the world, or the concerns of men. The wise man does not reverence them out of fear, but out of admiration for their excellence. As for their nature: they are compacted of the finest atoms.
9. The human soul is a corporeal substance; for if it were incorporeal it could neither act on the body, nor be acted on. Moreover, it is in contact with the body; but it is only the corporeal which can maintain contact with the corporeal. But the soul is a very refined, subtle body, composed of very minute smooth and rounded atoms, otherwise it could not permeate the entire body. Besides, if tbe soul were not so constituted, the body would lose something of its weight after death. The psychical atoms are of various kinds: some are of the nature of fire, others of the nature of air, others of the nature of wind or breath; according to the preponderance of one or the other kind, is the temperament of the human individual.
10. There are, however, in the soul atoms of an unknown and unnamed fourth quality, in virtue of which man is capable of feeling and thought. These atoms constitute the logikon (rational element) which is located in the breast, whereas the other atoms form the alogon, which is distributed through the whole body, and is the medium through which the mutual action of the logikon and the body is maintained. At death -- the atoms of the soul are dispersed; and since sensation becomes impossible when the combination of atoms is dissolved, it follows that the immortality of the soul is a mere chimera. But we have no need of immortality; for when death has come we are not present, and as long as we are here death has not come, so that death does not at all affect us. "Tota res ficta est pueriliter." Cic.
11. The Will is stimulated by the images in the mind, but it is not necessarily determined. As there is no heimarmenê, we are not controlled in our actions by an extrinsic force, our acts are our own, i.e., we are free. Without this liberty, praise and blame would have no meaning. Freedom of will is nothing more than chance applied to human actions. In the world everything is subject to chance, i.e., uncontrolled by necessity. The acts of human beings are like other things in this respect.
{1} The explanation of the collision of the atoms by their deviation from the perpendicular line of descent is peculiar to Epicurus; Democritus does not make this assumption.