Cleanthes of Assos was the second head of the Stoic school, succeeding Zeno of Citium after Zeno's death around 262 BC and leading the school until his own death around 230 BC. He is the least philosophically prominent of the three great founders of Stoicism — Zeno, Cleanthes, and Chrysippus — but he is the one from whom we have the most continuous surviving text: the Hymn to Zeus, a poem of forty-odd lines that is both the finest expression of early Stoic theology and the most vivid evidence of how the founders actually thought about the relationship between reason, nature, and the divine.
He was also, by the biographical accounts, one of the more remarkable human beings in the history of philosophy: a former prizefighter who worked nights watering gardens to support his philosophical studies, who was so devoted to Zeno's teaching that he refused any income that might have come from teaching others until he had fully worked out his own understanding, and who died, apparently voluntarily, at the reported age of ninety-nine.
Life
Cleanthes was born around 330 BC in Assos, a city on the coast of Asia Minor (modern Turkey). He arrived in Athens with, by the account of Diogenes Laërtius, only four drachmas to his name. He had been a boxer — a detail that ancient sources mention with some frequency and that his later philosophical life, characterized by extraordinary endurance and stubborn persistence, does nothing to contradict.
He became Zeno's student and remained so for nearly two decades, longer than any other student of whom we have record. Diogenes Laërtius preserves the detail that Cleanthes supported himself during this time by working at night — drawing water for a gardener and kneading dough for a baker — so that his days could be given entirely to philosophical study. When Athenian officials investigated where a fit young man of working age was getting his money, his employers appeared in court to confirm his employment. The court, apparently moved, gave him a gift of money. He refused it, at Zeno's advice.
This stubbornness — the same quality that kept him at Zeno's school despite whatever doubts others may have had about his intellectual capacity — characterized his philosophical work as well. He was not, by ancient report, naturally quick. Chrysippus, his own most brilliant student, reportedly said that he only needed the doctrines, not the demonstrations, since he could work out the arguments himself — implying that Cleanthes's teaching was sometimes insufficiently rigorous. Other ancient accounts note that fellow students mocked his slowness. He outlasted all of them.
He succeeded Zeno around 262 BC and led the school for thirty-two years, until around 230 BC. The ancient sources record that he died by choice: experiencing an ulcer in his mouth, he was advised by physicians to stop eating for two days to allow it to heal. He did so. When the physicians told him he could resume eating, he said he had gone too far down the road to turn back, and continued the fast until he died. He was ninety-nine.
Philosophy
Cleanthes made his most distinctive contributions in theology and cosmology — the areas of Stoic philosophy concerned with the nature of the divine principle, the Logos, and its relationship to the physical cosmos.
Zeno had established that the cosmos is rational and that the active principle — the Logos — pervades all matter. Cleanthes developed this account in a theological direction, emphasizing the unity and providential character of the divine reason more than Zeno had. Where Zeno's philosophical interest was primarily ethical — the question of how to live — Cleanthes was drawn to the question of how the cosmos worked, and how a rational understanding of the cosmos grounded the ethical conclusions Zeno had reached.
His physics followed Zeno's in identifying the Logos with Zeus and with fire — the active, fiery principle that pervades and organizes all matter. He emphasized the tension (tonos) of the pneuma, the active principle, as what holds the cosmos together and gives each thing its specific character. Different things have different degrees and qualities of tension, which accounts for their different natures: stones have the minimum tension required for physical coherence, plants have the tension characteristic of growth, animals have the tension of perception, and rational beings have the tension of reason.
His ethical contributions were largely devoted to developing and defending Zeno's foundational positions — virtue as the only genuine good, the dichotomy of preferred and indifferent things, the account of the passions as products of false judgment — rather than revising them. Ancient commentators noted that he sometimes differed from Zeno on specific questions, particularly in his more emphatic identification of the Logos with the sun as the ruling principle of the cosmos, a position not shared by Chrysippus. But the major doctrinal positions he inherited from Zeno he defended with the same tenacity he brought to his work as a student.
The Hymn to Zeus
The Hymn to Zeus is the most significant surviving text of early Stoicism. It is a poem in Greek hexameters, probably composed in the mid-third century BC, and it survives in a quotation preserved by the Neoplatonist philosopher Stobaeus. At approximately forty-three lines, it is the only extended text we have from any of the three founders of the Old Stoa; everything else survives only in fragments.
The hymn opens with an invocation of Zeus as the most powerful of the immortals and as the governing principle of all things:
"Most glorious of immortals, invoked by many names, ever all-powerful, Zeus, author of Nature, steering all things by law, hail to you. For it is right for mortals to address you, since from you we have our origin, we alone of all things that live and move as mortal creatures on the earth."
This is not conventional polytheistic address. The Zeus of the hymn is the Stoic Logos — the rational principle that governs the cosmos — described in the language of Greek religious tradition. The identification was deliberate and philosophically significant: Cleanthes was arguing that the god the Greeks worshipped under the name Zeus was, properly understood, the rational principle that the Stoics had identified through philosophy. Religion and philosophy point to the same reality.
The hymn then describes how the Logos governs all things, how even the apparent chaos and disorder of human action is ultimately contained within the rational order of the whole, and how the appropriate response to this recognition is to align one's own rational nature with the governing reason:
"Lead me, O Zeus, and thou, O Destiny, wherever your decrees have assigned me to go. I will follow without delay. And even if I am unwilling and in a cowardly spirit, I must still follow."
The final lines — preserved separately and cited by Epictetus and Marcus Aurelius — are among the most quoted in all of Stoic literature. The image of following fate willingly or being dragged unwillingly behind it became a touchstone of the Stoic attitude toward what cannot be changed.
Cleanthes and the Later Tradition
Cleanthes's influence on the later Stoic tradition is hard to separate from the Stoicism that Chrysippus systematized and that the Roman Stoics received. He transmitted Zeno's foundational doctrines, defended them against critics, and developed the theological dimensions that Chrysippus then systematized more rigorously.
What he contributed most distinctively — the Hymn to Zeus, the emphasis on the providential governance of the cosmos, the elaboration of the pneuma's tension as the organizing principle of physical nature — was absorbed into the tradition without being directly attributed in most later accounts. When Marcus Aurelius writes about the rational order of the cosmos, when Epictetus teaches that what happens is part of the rational whole, when Seneca argues that Providence governs events — they are drawing on a tradition whose theological scaffolding Cleanthes built.
He is also, in his own person, one of the more persuasive arguments for the Stoic way of life: a man who arrived penniless in a foreign city, worked nights to support a philosophical education no one else thought he was suited for, led one of the most influential philosophical schools in the ancient world for thirty-two years, and died at ninety-nine with enough equanimity to choose the moment. The philosophy he taught, he practiced.
Primary Sources
Cleanthes's own works survive only in fragments. The most important sources are:
- Hymn to Zeus — preserved in Stobaeus, Anthology 1.1.12. Available in most collections of Stoic fragments and in Greek with translation in Long and Sedley's The Hellenistic Philosophers.
- Diogenes Laërtius. Lives of the Eminent Philosophers, Book 7. Trans. R.D. Hicks. Available via Perseus Digital Library. The primary ancient account of Cleanthes's life and doctrines.
- Long, A.A. and Sedley, D.N. The Hellenistic Philosophers, Vol. 1. Cambridge University Press, 1987. The most important scholarly collection of Stoic fragments, with Cleanthes's fragments collected and translated.
Further Reading
- Long, A.A. Hellenistic Philosophy. University of California Press, 1986. Standard scholarly introduction with treatment of Cleanthes in context.
- Lapidge, M. "Stoic Cosmology." In The Stoics, ed. John M. Rist. University of California Press, 1978. Covers Cleanthes's distinctive contributions to Stoic physics.
- Thom, Johan C. Cleanthes' Hymn to Zeus. Mohr Siebeck, 2005. The most detailed scholarly study of the hymn.