Sphaerus (, sometimes transliterated as Sphaeros; – ) of Borysthenes or the Bosphorus, was a Stoic philosopher.

Life

Sphaerus studied first under Zeno of Citium, and afterwards under Cleanthes. He taught in Sparta, where he acted as advisor to Cleomenes III. He moved to Alexandria at some point, (possibly when Cleomenes himself was exiled there in 222 BC) where he lived in the court of Ptolemy IV Philopator.

Ideas

Little survives of his works, but Sphaerus had a considerable reputation among the Stoics for the accuracy of his definitions.

Diogenes Laërtius and Athenaeus tell a story of how he once saved himself from admitting that he had been deceived by a trick played upon him by King Ptolemy:

Writings

According to Diogenes Laërtius, Sphaerus wrote the following works:

• Περὶ κόσμου δύο – On the Universe (two books)

• Περὶ στοιχείων – On the Elements

• [Περὶ] σπέρματος – [On] Seed

• Περὶ τύχης – On Fortune

• Περὶ ἐλαχίστων – On the Smallest Things

• Πρὸς τὰς ἀτόμους καὶ τὰ εἴδωλα – Against Atoms and Images

• Περὶ αἰσθητηρίων – On the Senses

• Περὶ Ἡρακλείτου πέντε διατριβῶν – On Heraclitus (five lectures)

• Περὶ τῆς ἠθικῆς διατάξεως – On the Arrangement of Ethics

• Περὶ καθήκοντος – On Duty

• Περὶ ὁρμῆς – On Impulse

• Περὶ παθῶν δύο – On Passions (two books)

• Περὶ βασιλείας – On Kingship

• Περὶ Λακωνικῆς πολιτείας – On the Lacedaemonian Constitution

• Περὶ Λυκούργου καὶ Σωκράτους τρία – On Lycurgus and Socrates (three books)

• Περὶ νόμου – On Law

• Περὶ μαντικῆς – On Divination

• Διαλόγους ἐρωτικούς – Dialogues on Love

• Περὶ τῶν Ἐρετριακῶν φιλοσόφων – On the Eretrian Philosophers

• Περὶ ὁμοίων – On Things Similar

• Περὶ ὅρων – On Terms

• Περὶ ἕξεως – On Habits

• Περὶ τῶν ἀντιλεγομένων τρία – On Contradictions (three books)

• Περὶ λόγου – On Discourse

• Περὶ πλούτου – On Wealth

• Περὶ δόξης – On Glory

• Περὶ θανάτου – On Death

• Τέχνης διαλεκτικῆς δύο – Art of Dialectics (two books)

• Περὶ κατηγορημάτων – On Predicates

• Περὶ ἀμφιβολιῶν – On Ambiguity

• Ἐπιστολάς – Letters

Notes

References

The surviving fragments of Sphaerus' writings are collected in: