Lives of Eminent Philosophers (1.prol.6-1.prol.10)

But the advocates of the theory that philosophy took its rise among the barbarians go on to explain the different forms it assumed in different countries. As to the Gymnosophists and Druids we are told that they uttered their philosophy in riddles, bidding men to reverence the gods, to abstain from wrongdoing, and to practise courage. That the Gymnosophists

They hold discourse of justice, and deem it impious to practise cremation; but they see no impiety in marriage with a mother or daughter, as Sotion relates in his twenty-third book. Further, they practise divination and forecast the future, declaring that the gods appear to them in visible form. Moreover, they say that the air is full of shapes which stream forth like vapour and enter the eyes of keen-sighted seers. They prohibit personal ornament and the wearing of gold. Their dress is white, they make their bed on the ground, and their food is vegetables, cheese,[*] and coarse bread; their staff is a reed and their custom is, so we are told, to stick it into the cheese and take up with it the part they eat.

With the art of magic they were wholly unacquainted, according to Aristotle in his Magicus and Dinon in the fifth book of his History Dinon tells us that the name Zoroaster, literally interpreted, means star-worshipper[*]; and Hermodorus agrees

The last-named author says that according to the Magi men will live in a future life and be immortal, and that the world will endure through their invocations.[*] This is again confirmed by Eudemus of Rhodes. But Hecataeus relates that according to them the gods are subject to birth. Clearchus of Soli in his tract On Education further makes the Gymnosophists to be descended from the Magi; and some trace the Jews also to the same origin. Furthermore, those who have written about the Magi criticize Herodotus. They urge that Xerxes would never have cast javelins at the sun nor have let down fetters into the sea, since in the creed of the Magi sun and sea are gods. But that statues of the gods should be destroyed by Xerxes was natural enough.

The philosophy of the Egyptians is described as follows so far as relates to the gods and to justice. They say that matter was the first principle, next the four elements were derived from matter, and thus living things of every species were produced.

The sun and the moon are gods bearing the names of Osiris and Isis respectively; they make use of the beetle, the dragon, the hawk, and other creatures as symbols of divinity, according to Manetho in his Epitome of Physical Doctrines, and Hecataeus in the first book of his work On the Egyptian Philosophy. They also set up statues and temples to these sacred animals because they do not know the true form of the deity.