of that kind. But, on the other hand, he said, that vice was sufficient of itself to cause unhappiness, even if the goods of the body and the external goods were present in the greatest possible degree. He also asserted that the virtues did not reciprocally follow one another, for that it was possible for a prudent, and just, and impartial man, to be incontinent and intemperate; and he said, that the wise man was not destitute of passions, but endowed
He also used to define friendship as an equality of mutual benevolence. And he divided it into the friendship of kindred, and of love, and of those connected by ties of hospitality. And he said, that love was divided into sensual and philosophical love. And that the wise man would feel the influence of love, and would occupy himself in affairs of state, and would marry a wife, and would live with a king. And as there were three kinds of life, the speculative, the practical, and the voluptuous, he preferred the speculative. He also considered the acquisition of general knowledge serviceable to the acquisition of virtue. As a natural philosopher, he was the most ingenious man that ever lived in tracing effects back to their causes, so that he could explain the principles of the most trifling circumstances; on which account he wrote a great many books of commentaries on physical questions.
He used to teach that God was incorporeal, as Plato also asserted, and that his providence extends over all the heavenly bodies; also, that he is incapable of motion. And that he governs all things upon earth with reference to their sympathy with the heavenly bodies. Another of his doctrines was, that besides the four elements there is one other, making the fifth, of which all the heavenly bodies are composed; and that this one possesses a motion peculiar to itself, for it is a circular one. That the soul is incorporeal, being the first ἐντελέχεια; for it is the ἐντελέχεια of a physical and organic body, having an existence in