Lives and Opinions of Eminent Philosophers

​After Zeno, Sphaerus of the Bosporus also attended the lectures of this Cleanthes, as we have mentioned before; and having made sufficient progress in philosophical discourses, he departed for Alexandria to the court of Ptolemy Philopator. Once, when a discussion arose concerning whether the wise man will form mere opinions, and Sphaerus stated that he will not, the king, wishing to refute him, ordered wax pomegranates to be set before him; and when Sphaerus was deceived, the king cried out that he had given his assent to a false presentation. To him Sphaerus replied apt and neatly, saying that he had assented in such a way, not that they were pomegranates, but that it was reasonable that they were pomegranates; and that an apprehensive presentation differs from what is reasonable. And to Mnesistratus, who accused him of saying that Ptolemy was not a king, [he answered] that Ptolemy, being of such a character, was indeed a king as well.

​He wrote the following books: On the Cosmos, two books. On the Elements. On Seed. On Fortune. On the Smallest Parts. Against Atoms and Images. On the Sense Organs. On Heraclitus, five lectures. On the Ethical Disposition. On Duty. On Impulse. On Passions, two books. On Kingship. On the Laconian Constitution. On Lycurgus and Socrates, three books. On Law. On Divination. Erotic Dialogues. On the Eretrian Philosophers. On Similar Things. On Definitions. On Habit. On Contradictory Matters, three books. On Reason. On Wealth. On Reputation. On Death. Art of Dialectic, two books. On Predicates. On Ambiguities. Letters.