Zeno of Citium

Zeno of Citium was the founder of Stoicism, the philosophy that taught that virtue is the only true good and that a happy life is one lived in agreement with nature and reason. A merchant from Cyprus who came to philosophy in Athens, he began teaching around 300 BCE in a painted colonnade, the Stoa Poikile, from which his school took its name. None of his writings survive complete, but the school he founded became the most influential philosophy of the Roman world.

Zeno was born around 334 BCE in Citium, a town on the south coast of Cyprus, close to modern Larnaca. Citium had a mixed population of Greeks and Phoenicians, and ancient writers often called Zeno a Phoenician; his father's name, Mnaseas, could be read in either language. Modern scholars disagree about his background, and the question probably mattered less in his own time than it later did. What is clear is that he wrote and taught in Greek and received a Greek education.

Most of what is known about his life comes from Diogenes Laertius, a biographer writing some five hundred years later, whose account mixes fact with anecdote. According to the best-known story, Zeno was a trader who was shipwrecked near Piraeus while carrying a cargo of purple dye from Phoenicia. Stranded in Athens, he sat in a bookshop reading Xenophon's memoir of Socrates and asked where men like that could be found. The bookseller pointed to Crates of Thebes, a Cynic philosopher who happened to be passing, and Zeno became his pupil.

The Cynics, followers of Diogenes of Sinope, rejected wealth, convention and social status, and lived in deliberate poverty to show that virtue alone was enough for happiness. Zeno absorbed their moral seriousness and their simple way of life, but ancient stories suggest he was too modest for their deliberate shamelessness. He went on to study with other teachers: Stilpo of the Megarian school, the logicians Diodorus Cronus and Philo, and Polemo, head of Plato's Academy. From these sources he built a system that was more than a way of life. It had a logic, a physics and an ethics, each supporting the others.

Around 301 BCE Zeno began to teach in the Stoa Poikile, a public colonnade on the edge of the Athenian agora decorated with famous paintings. Unlike Epicurus, who taught in a private garden, Zeno taught in the open, and anyone could listen. His followers were at first called Zenonians, then Stoics, after the place.

He lived simply and was respected for his self-discipline. Antigonus II Gonatas, the Macedonian king who dominated Athens in these years, admired him and invited him to his court; Zeno declined on grounds of age and sent two of his students instead. The Athenians honoured him with a golden crown and a bronze statue, and after his death voted him a tomb at public expense, praising him for leading the young towards virtue. According to Diogenes Laertius he died around 262 BCE, at an advanced age, apparently by his own choice after a fall. The details of his last years, like many details of his life, are uncertain.

Zeno divided philosophy into three parts: logic, physics and ethics. It is hard to separate his own views from those of his successors, especially Chrysippus, who systematised Stoicism a generation later, but the main outlines go back to him.

In physics Zeno drew on Heraclitus. The universe, he held, is a single living whole, pervaded by a divine, rational fire or breath that shapes passive matter. This active principle, called logos, reason, is identical with god, nature and fate. Everything happens according to its plan, and the cosmos passes through endless cycles in which it is consumed by fire and then reborn. Human souls are fragments of this divine fire, which is why human beings are rational.

In ethics he taught that the goal of life is to live in agreement with nature, which for a rational being means living according to reason. Virtue, the perfection of reason, is the only good, and vice the only evil. Everything else, including health, wealth, reputation, pain and even death, is indifferent: such things do not make a person good or bad, happy or unhappy. Zeno added an important refinement to Cynic thought. Some indifferent things are naturally preferred, such as health, and others dispreferred, such as illness, so it is reasonable to choose them, but they should never be confused with the good itself. The passions, such as fear, greed and grief, he regarded as mistaken judgements and disturbances of the mind contrary to reason, which the wise person learns to eliminate.

In logic and the theory of knowledge he taught that some sense impressions are so clear that they compel assent and can be the basis of knowledge. A famous illustration, preserved by Cicero, has Zeno showing an open hand for an impression, slightly closed fingers for assent, a clenched fist for firm grasp, and the fist gripped by the other hand for knowledge, which only the sage possesses.

Zeno wrote a number of books, of which only titles and brief quotations survive. The most notorious was the Republic, an early work written under Cynic influence, which described an ideal community of the wise without temples, law courts, money or traditional marriage, bound together by love and shared virtue. Later Stoics were sometimes embarrassed by it. Other titles include On Life According to Nature, On Impulse, On Passions and On the Universe.

After Zeno's death the school was led by Cleanthes and then by Chrysippus, whose writings made Stoicism the dominant philosophy of the Hellenistic world and a rival to the Epicureans and the Academy. The Stoics brought the idea of a universal law of nature, binding on all rational beings, into Greek and Roman thought. In the Roman Empire, Stoicism found its most famous voices in Seneca, Epictetus and Marcus Aurelius, whose writings, unlike Zeno's, survive. Through them, Stoic ethics shaped Christian moral thought, Renaissance Neostoicism, modern ideas of natural law and, in recent decades, popular self-help and cognitive therapy. Zeno's place in that long story is covered further on the page on Hellenistic and Roman philosophy. He is also remembered in modern Greece and Cyprus as one of the most influential thinkers either produced.