Professor Boas, in contrasting Asiatic mythology with Greek philosophy, remarks: "The Asiatic myths assumed the existence of beings beyond the world, not subject to mundane laws, who made and controlled the course of events. There was no reason why they should have made a world. They seemed to be living as divine a life without it as with it. The question was one which persisted in Asiatic thought, and when Christianity became dominant in Europe, much of its theologians' time was spent in answering it. The only plausible answer then was that God made the world because He felt like it. For no reason could be given sufficiently compelling to sway the will of the Omnipotent. But such an answer was unsatisfactory to the Greek. In his philosophy all this is changed. No god steps out of the machine to initiate cosmic history. The First Cause is a physical substance, some material thing, which operates by the laws of its own nature. Its every movement is theoretically open to the scrutiny of reason. And hence, a scientific rather than a religious answer can be given to every question." At the beginning of the Christian era, the cultured Romans were stoics or epicureans. The poet Lucretius was an epicurean who regarded the belief in the gods as a product of the terrors of primitive man and recommended that the mind should be emancipated from the fear of the gods and argued against the immortality of the soul. Seneca, Epictetus, and Marcus Aurelius were stoics. Cicero insinuates that the gods are only poetical creations, that the popular doctrine of punishment in a world to come is only an idle fable, and is uncertain whether the soul is immortal. Seneca wrote against the religion of his country, and the philosophy of cultured Romans of the time of the physician Galen tended towards atheism. The prime factor of Greek philosophy was the insistence on intelligence and knowledge, and by these means it reached its pinnacle of reasoning. The blight that exterminated all scientific progress, with the fall of the Roman Empire, carried with it the neglect of the Greek thinkers. Similar to the retrogression of scientific thought, traced in former chapters, is the corresponding retrogression in philosophic thought. In place of the free inquiry of the Greeks we see arising the theology of Clement of Alexandria, Origen, St. Augustine, and finally that of St. Thomas Aquinas. At the time of St. Augustine most of the cultural Greek writings had disappeared in western Europe. The greatest store of Greek thought was in the hands of the Arab scholars and led to a marked scepticism, as we see manifested in the writings of the Spanish Moors.