Not only is Being, for Heracleitus, identical with not-being, but everything in the universe has in it its own opposite. Every existent thing is a "harmony of opposite tensions." A harmony contains necessarily two opposite principles which, in spite of their opposition, reveal an underlying unity. That it is by virtue of this principle that everything in the universe exists, is the teaching of Heracleitus. All things contain their own opposites within them. In the struggle and antagonism between hostile principles consists their life, their being, their very existence. At the heart of things is conflict. If there were no conflict in a thing, it would cease to exist. This idea is expressed by Heracleitus in a variety of ways. "Strife," he says, "is the father of all things." "The one, sundering from itself, coalesces with itself, like the harmony of the bow and the lyre." "God is day and night, summer and winter, war and peace, satiety and hunger." "Join together whole and unwhole, congruous and incongruous, accordant and discordant, then comes from one all and from all one." In this sense, too, he censures Homer for having prayed that strife might cease from among gods and men. If such a prayer were granted, the universe itself would pass away.
Side by side with this metaphysic, Heracleitus lays down a theory of physics. All things are composed of fire. "This world," he says, "neither one of the gods nor of the human race has made; but it is, it was, and ever shall be, an eternally living fire." All comes from fire, and to fire all returns. "All things are exchanged for fire and fire for all, as wares for gold and gold for wares." Thus there is only one ultimate kind of matter, fire, and all other forms of matter are merely modifications and variations of fire. It is clear for what reason Heracleitus enunciated this principle. It is an exact physical parallel to the metaphysical principle of Becoming. Fire is the most mutable of the elements. It does not remain the same from one moment to another. It is continually taking up matter in the form of fuel, and giving off equivalent matter in the form of smoke and vapour. The primal fire, according to Heracleitus, transmutes itself into air, air into water, and water into earth. This he calls "the downward path." To it corresponds "the upward path," the transmutation of earth into water, water to air, and air to fire. All transformation takes place in this regular order, and therefore, says Heracleitus, "the upward and the downward path are one."
Fire is further specially identified with life and reason. It is the rational element in things. The more fire there is, the more life, the more movement. The more dark and heavy materials there are, the more death, cold, and not-being. The soul, accordingly, is fire, and like all other fires it continually burns itself out and needs replenishment. This it obtains, through the senses and the breath, from the common life and reason of the [{79}] world, that is, from the surrounding and all-pervading fire. In this we live and move and have our being. No man has a separate soul of his own. It is merely part of the one universal soul-fire. Hence if communication with this is cut off, man becomes irrational and finally dies. Sleep is the half-way house to death. In sleep the passages of the senses are stopped up, and the outer fire reaches us only through breath. Hence in sleep we become irrational and senseless, turning aside from the common life of the world, each to a private world of his own. Heracleitus taught also the doctrine of periodic world-cycles. The world forms itself out of fire, and by conflagration passes back to the primitive fire.
In his religious opinions Heracleitus was sceptical. But he does not, like Xenophanes, direct his attacks against the central ideas of religion, and the doctrine of the gods. He attacks mostly the outward observances and forms in which the religious spirit manifests itself. He inveighs against the worship of images, and urges the uselessness of blood sacrifice.
With the Eleatics he distinguishes between sense and reason, and places truth in rational cognition. The illusion of permanence he ascribes to the senses. It is by reason that we rise to the knowledge of the law of Becoming. In the comprehension of this law lies the duty of man, and the only road to happiness. Understanding this, man becomes resigned and contented. He sees that evil is the necessary counterpart of good, and pain the necessary counterpart of pleasure, and that both together are necessary to form the harmony of the world. Good and evil are principles on the struggle [{80}] between which the very existence of things depends. Evil, too, is necessary, has its place in the world. To see this is to put oneself above pitiful and futile struggles against the supreme law of the universe.
EMPEDOCLES
Empedocles was a man of Agrigentum in Sicily. The dates of his birth and death are placed about 495 and 435 B.C. respectively. Like Pythagoras, he possessed a powerful and magnetic personality. Hence all kinds of legends quickly grew up and wove themselves round his life and death. He was credited with the performance of miracles, and romantic stories were circulated about his death. A man of much persuasive eloquence he raised himself to the leadership of the Agrigentine democracy, until he was driven out into exile.