Posidonius
Greek polymath who spread Stoicism and studied tides.
Posidonius, a Greek from Apamea in Syria, was a politician, astronomer, astrologer, geographer, historian, mathematician, and teacher. He was widely regarded as the most learned person of his era, and possibly of the entire Stoic school. After learning Stoic philosophy from Panaetius in Athens, he spent many years traveling through Spain, Africa, Italy, Gaul, Liguria, Sicily, and the eastern Adriatic coast, conducting scientific research. He eventually settled in Rhodes as a teacher, where his reputation drew many students. Alongside Panaetius, he did the most to introduce Stoicism to the Roman world through his writings and lectures, and became acquainted with prominent figures such as Pompey and Cicero. His works are now lost, but later writers relied heavily on them; the titles and subjects of over twenty are known. Like other middle-period Stoics, he blended ideas from earlier Stoics with those of Plato and Aristotle. A polymath, he was deeply interested in natural science, geography, natural history, mathematics, and astronomy, and worked to measure the Sun’s distance and size, calculate the Earth’s diameter, and study the Moon’s effect on tides.
- died
- c. 51 BC
- field
- Philosophy, astronomy, geography, history, mathematics
- nationality
- Greek (native of Apamea, Syria)
- known_for
- Polymath of the Stoic school; works on tides, Earth's diameter, and Sun's distance; spreading Stoicism to Rome
Quick Facts
- Region
- Western philosophy
- Era
- Hellenistic philosophy
- Birth Date
- c. 135 BC
- Birth Place
- Apamea Seleucid Empire
- Death Date
- c. 51 BC (aged 83–84)
- Death Place
- Rhodes or Rome
- School Tradition
- Stoicism
- Main Interests
- Astronomy, geography, history, mathematics, meteorology, philosophy, physics
- Notable Ideas
- Cosmic sympathy
Facts from the source article.
Lore & Background
He expressed no love for his native city and mocked its inhabitants. As a young man he moved to Athens and studied under Panaetius, the leading Stoic philosopher of the age. Around the 90s BC he embarked on voyages around the Mediterranean, gathering scientific data and observing customs in Greece, Hispania, Italy, Sicily, Dalmatia, Gaul, Liguria, North Africa, and the eastern shores of the Adriatic. In Hispania, he observed tides much higher than in the Mediterranean, wrote that daily tides relate to the Moon's orbit, and hypothesized about yearly tidal cycles synchronized with equinoxes and solstices. In Gaul, he studied the Celts, describing customs such as nailing skulls to doorways and noting that they honored the Druids as philosophers.
Reader's Guide
Posidonius was celebrated as a polymath throughout the Graeco-Roman world, attempting to create a unified system for understanding the human intellect and the universe. He wrote on physics, astronomy, astrology, seismology, geology, hydrology, botany, ethics, logic, mathematics, history, natural history, anthropology, and tactics. None of his works survives intact; only fragments remain, though the titles and subjects of more than twenty books are known. Writers such as Strabo and Seneca provide most of the information about his life and works. For Posidonius, philosophy was the dominant master art, and all sciences were subordinate to it. He accepted the Stoic categorization of philosophy into physics, logic, and ethics, comparing them to a living being. He was syncretic, following earlier Stoics but also making use of Plato and Aristotle. Under Posidonius, Rhodes eclipsed Athens as the new centre for Stoic philosophy in the 1st century BC. His legacy endures through later writers who mined his lost works for information, and through his influence on Roman figures such as Pompey and Cicero, who called him 'my teacher' and 'my dear friend.'
Did You Know?
- Posidonius was nicknamed 'the Athlete' (Ἀθλητής).
- He served as one of the Prytaneis, the most important political office in Rhodes.
- He was chosen for at least one embassy to Rome in 87/86 BC during the Marian and Sullan era.
- His grandson, Jason of Nysa, succeeded him as head of the school on Rhodes.
Frequently Asked Questions
What are Posidonius's main areas of study?
Beyond Stoic philosophy, Posidonius researched tides, measured the Earth's diameter, and estimated the distance to the Sun. He also wrote on geography, history, and mathematics, making him a true polymath of the ancient world.
How did Posidonius spread Stoicism to Rome?
After training under Panaetius in Athens, Posidonius settled in Rhodes as a teacher and drew students from across the Mediterranean. Roman leaders such as Pompey and Cicero became familiar with his ideas, making him a key bridge between Greek Stoic thought and the Roman intellectual world.
Where did Posidonius teach and why was Rhodes significant?
Posidonius established his teaching practice in Rhodes, where his growing reputation attracted scholars from many regions. The island's strategic location and existing academic tradition made it an ideal hub for disseminating his philosophical and scientific work.
Why is Posidonius considered important in the history of philosophy?
He is credited, alongside Panaetius, with doing the most to introduce and popularize Stoic philosophy among the Roman elite. His wide-ranging scholarship also set a model for the polymath ideal, influencing how later thinkers approached the relationship between philosophy and natural science.
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