Greek philosophy is as brilliant as every other creation of the Greek intellect. The line of thinkers which that little nation produced in three centuries has no parallel in the history of thought, and every conceivable variety or cast of speculation made its appearance. But Greek thought became distorted by religion. It turned away from science to “spiritual truths”. It has shown for all time how futile and mischievous is that high sounding appeal for us to turn from science to “spiritual truths”.

Greek civilization first reached a high development in the Mediterranean fringe of Asia Minor or on the islands off the coast, and this points to an influence of the conquering Persians. The early Greek philosophers nearly all belong to this region. Philosophy was born out of the inspiration of Persian religion, and the Greek desire to improve on the novelties of their enemies. But the most essential condition to bear in mind is the liberty the Greeks enjoyed in Asia Minor. They were in a colonial world. They were free to speculate.  

This Greek fringe on the coast of Asia Minor was known as Ionia, and the first school of thinkers is known as the Ionic school. From the start it was more scientific than metaphysical. Its leaders studied Nature, and man as a part of Nature. They sought the first principles of things, not in abstract metaphysical formulae, and not at all in religion, but in physical realities. Thales, the father of philosophy, thought that water was the original element out of which all other things came. Then the religious revival took place, and the next Greek thinker said that “the infinite”—not God, but something hopelessly indefinite—was the first principle. The third, Anaximenes, took air—an infinite quantity of air—as the starting point. The fourth, Xenophanes, said that the primordial element was earth. The fifth chose fire.

This was the birth of speculation about Nature and guesses were bound to be crude. The world was being interpreted on natural principles, without the absurdities of the Babylonian creation. Xenophanes, a skeptic, noted the repulsiveness of the legends about gods. Heraclitus, denied that the world was created by gods, because it was an eternally changing substance. Empedocles of the Greek colony in Sicily, whose mind was a strange blend of mysticism and science, maintained that there was only one God, “a sacred and unutterable mind”. In the fifth century BC, God was conceived as people do today.  

These speculations about the universe, besides showing men how to think without gods, led on to a belief in evolution. If there was no beginning, contrary to the Babylonians, if the universe was eternal, and there was one primordial element of all things, then there has been an eternal evolution of this element into the contents of the universe today. Every one of these early Greek thinkers believed that, and the doctrine was further developed by two of the boldest of them all, Leucippus and Democritus.

About the middle of the fifth century, Leucippus, another Ionian Greek, hit upon the idea that matter must be composed of atoms. The universe consisted of an infinite number of atoms, of different shapes and sizes, which have, without any directing mind, gradually come together in the bodies we see today. Democritus developed this idea with real scientific genius. All the contents of the universe, including man, were the result of an eternal, unguided, quite purposeless tossing and mingling of the atoms. Democritus, moreover, while completely rejecting all religion, worked out an elevated system of humanitarian morals.

Three very great principles had been fixed—the eternity of the world and its independence of gods, the existence of atoms, and the fact of evolution. At the same time these early thinkers observed much in astronomy, and they were good mathematicians. Many of them visited Egypt, and learned whatever the priests of Egypt could tell them. They obtained some idea of the immense size of the sun and of the vastness of the universe, and Pythagoras actually declared, for the first time in the history of thought, that the earth revolved round the sun.  

Here was a promising foundation for science, but religion hampered its development and diverted thought to other channels. Anaxagoras took the speculations of the physicists to Athens, and the democracy made him fly for his life for uttering such impieties, although he judiciously blended his science with some theological mysticism.

Another train of thought, in Greece itself, had meanwhile led to skepticism. There arose a school of Sophists who took pleasure in contending that the mind could come to no valid conclusions whatever. Protagoras talked about the gods even less respectfully than Confucius:

I cannot say whether they exist or not. Life is too short for such difficult investigations.

Both this man and Anaxagoras were great friends of Pericles, and these skeptical ideas pervaded the whole group of artists and thinkers of the Golden Age. But—partly in political opposition to the aristocratic party, to which they belonged—the democracy raged against them, and Protagoras in turn had to hurry from the country.

In these circumstances Socrates, the leader of a different line of Greek thinkers, came upon the scene at Athens, in the second half of the fifth century BC. He was put to death in 399 BC. This great thinker and moralist, a man of the highest and most independent character, met death on the grotesque and false charge of corrupting the young men of Athens.

What did it matter whether the ultimate principle was air or water or fire? Or whether there were atoms? What did matter was that human conduct should be effectively guided and that men should understand the real nature of justice and “the good”. Socrates turned the brilliant race aside from the foundations of science which had been laid, and he provided instead the bases of philosophy and ethics. Pythagoras, the Greek who had first realized that the earth traveled round the sun, yet a strange mystic, had preceded him. Philosophy was to be profoundly religious. Religion was to become a philosophy.

Socrates wrote no works. His ideas are known only from his pupils, Plato especially, and Xenopbon. Plato has given them his own more mystical colour. Like Socrates, he believed in one God, an eternal spiritual being such as modernists now offer us. He believed intensely in the immortality of the soul, and provided feeble “proofs” of it, now laughable. He belittled matter and the flesh, and traced everything good, true and beautiful to “spirit”. Plato set a fashion which has not died. The verbiage that befogs the minds of people today is from this glorification of spirit and depreciation of matter. It begs the question whether the mind is or is not material. Plato shows that monotheism could be reached without a gleam of revelation, and anticipated the ethic of Christ centuries before he was born.

Greek experience shows anyone’s philosophy of life, materialist or spiritualist, religious or nonreligious, makes no difference to their moral ideal. The materialist Democritus had as lofty sentiments as the mystic Pythagoras or the spiritual Plato. The skeptical Alcidamas, a Sophist and atheist, was the first man to denounce slavery, thousands of years before Christianity did. The atheistic Epicurus had as sane and sober a conception of character as the theistic Aristotle. Morality is a human matter. Its roots are in human experience, not in religion.

Aristotle was far less mystic than Plato. His god, or Supreme Mind, was unconscious of sublunary matters, and therefore not a universal providence or a creator. Nor did he believe in personal immortality. His system of thought is one of the most learned and original ever given to the world. He summarized all the science of his time, and he made a science of ethics and politics. Unfortunately, he was also a metaphysician. He thought that besides our knowledge of Nature (“ta physica”) it was possible to get a knowledge of things beyond the physical (“ta meta ta physica”, or metaphysics), and these were more important and more worthy of the mind. In that sense Aristotle, though for his time a great scientific man, joined Plato in leading human thought astray.

Yet, all these thinkers were high moral idealists. Wicked Pagan Greece produced a line of unsurpassed moralists, a strange mystery to Christians for whom there is only one ethical route in the whole universe. Athens was not so much the city of vice as the greatest morality making center the world has ever known. It culminated in the Stoic School. The philosophers used to gather groups about them in their gardens or in public places, and one of them, Zeno, chose the Painted Colonnade (Stoa Poikile). Hence the Stoic philosophy.

It was not a religion. Zeno and the Stoics spoke of God but he was a material entity, and he was not the author and vindicator of the moral law. The law was an eternal part of Nature, and a man was urged to live in harmony with Nature. This philosophy inspired, in the Roman world, the greatest humanitarian movement ever known until modern times. It kept educated Romans at a high level of character, and it produced Christ-like austere moralists such as Epictetus and Marcus Aurelius. This austere and, in its more sober Roman form, effective of moral systems was a dogmatic materialism! The Stoics ridiculed the idea of spirit and free will, which we are asked to regard as the indispensable bases of any moral conduct.

Passing over schools of Pantheists, Cynics, and Sophists, Greek philosophy ended in the system of Epicurus. He built upon science, gathering together all that the early scientists had said about the universe. He spoke of gods as beings somewhere out in the abysses of space with whom a sensible man need not concern himself. Like Buddha and Confucius, he was a practical atheist. If there were any gods, they had nothing to do with us. His ethics, one of the sanest systems given to the world, had nothing to do with religion. Moral law was social law. Epicurus was—contrary to the libelous, ridiculous idea of his philosophy which Christian writers put into circulation—one of the most abstemious of men. Tranquillity, the quiet life, was his idea. If he was wrong at all, it was in being too ascetic.

But Athens was now in full decay. The work of Greece was done. The republic, enfeebled by a long civil war, had fallen. The monarchy of the Macedonians overshadowed it. The philosophy of Epicurus reflects the time, the wish for a quiet, passionless life. The work of civilization passed on to Rome.