The intellectual condition of the different parts of the empire was quite unsatisfactory. In this respect there had been a real decline. High mental culture is not as independent of political circumstances as is private morality. Besides, the progress of high mental culture and that of morality are not exactly parallel. Marcus Aurelius was certainly a better man than all the old Greek philosophers. Yet his positive notions in regard to the realities of the universe were inferior to those of Aristotle and Epicurus; for he believed at times in dreams and omens, and in the gods as complete and distinct personalities. The world was then undergoing a moral improvement and an intellectual decline. From Tiberius to Nerva this decline is very perceptible. The Greek genius, with a force, originality, and copiousness which have never been equalled, had in the course of several centuries created the rational encyclopædia, the normal discipline of the mind. This wonderful movement commenced with Thales, and the earliest Ionian schools (600 years before Christ), and was stopped about B.C. 120. The last survivors of these five centuries of intellectual progress, Apollonius of Perga, Eratosthenes, Aristarchus, Hero, Archimedes, Hipparchus, Chrysippus, Carneades, and Panetius, had departed, leaving no successors. Only Posidonius and a few astronomers kept up the ancient reputation of Alexandria, Rhodes, and Pergamus. Greece, however fertile in creative genius, had not extracted from her science and philosophy any system of popular instruction or remedy against superstition. Possessing admirable scientific institutes, Egypt, Asia Minor, and Greece herself were at the same time given over to the most senseless credulity. But if science does not succeed in getting the upper hand over superstition, superstition will extinguish science. Between these two opposing forces, the combat is to the death.