Zeno of Citium (Ζήνων ὁ Κιτιεύς, Zēnōn ho Kitieŭs) (334 BC - 262 BC) was a Greek philosopher from Citium (Κίτιον), Cyprus. Zeno was the founder of the Stoic school of philosophy which he taught in Athens, from about 300 BC. Based on the moral ideas of the Cynics, Stoicism laid great emphasis on the goodness and peace of mind which would arise from living a life of virtue in accordance with nature. It would prove to be very successful, and flourished as the dominant philosophy from the Hellenistic period through to the Roman era.
Zeno was also a merchant until the age of 42, when he started the Stoic school of philosophy. The story goes that, after a shipwreck, Zeno wandered into a bookshop in Athens and was attracted to the works of Socrates. He asked the librarian how to find the man. In response, the librarian pointed to Crates of Thebes, later to become his teacher. Named for his teaching platform, the Stoa (Greek for "porch"), his teachings were the beginning of Stoicism. None of Zeno's own works have survived to modern times; however, his teachings have been passed on, including his main concept that "tranquility can best be reached through indifference to pleasure and pain."
Zeno was described as a haggard, tanned person, living a spare, ascetic life. This coincides with the influences of Cynic teaching, and was, at least in part, continued in his Stoic philosophy.
Diogenes Laërtius, biographer of the Greek philosophers, left the most extensive writings about Zeno's life with his work Lives of Eminent Philosophers. Although these writings miss deeper introspection into the philosophical ideas of Zeno, the anecdotal descriptions leave a colorful image of the historical figure Zeno. Some examples:
Zeno preached that "man conquers the world by conquering himself." He lectured his students on the value of apatheia, which he explained to be "the absence of passion." Only by controlling one's emotion and physical desire, he argued, could we develop wisdom and the ability to apply it. By developing an indifference to pain and pleasure through meditation, the practicing Stoic will develop a wisdom stemming from suppressing the influence of passions, and ultimately, will attain wisdom. He is the inventor of the concept of Kathekon.
Zeno died around 262 BC. Laërtius reports about his death: "As he left the school, he tripped, fell and broke a toe. Hitting the ground with his hand, he cited words of Niobe: "I am coming, why do you call me thus?". Since the Stoic sage was expected to always do what was appropriate (kathekon) and Zeno was very old at the time, he felt it appropriate to die and consequently strangled himself.
During his lifetime, Zeno received appreciation for his philosophical and pedagogical teachings. Amongst other things, Zeno has been honored with the golden crown, and a tomb was built in honor of his moral influence on the youth of his era.
Zeno stretched out his fingers, and showed the palm of his hand, - "Perception," - he said, - "is a thing like this."- Then, when he had closed his fingers a little, - "Assent is like this." - Afterwards, when he had completely closed his hand, and showed his fist, that, he said, was Comprehension. From which simile he also gave that state a name which it had not before, and called it katalepsis. But when he brought his left hand against his right, and with it took a firm and tight hold of his fist:
- "Knowledge" - he said, was of that character; and that was what none but a wise person possessed.
Zeno, then, defines nature by saying that it is artistically working fire, which advances by fixed methods to creation. For he maintains that it is the main function of art to create and produce, and that what the hand accomplishes in the productions of the arts which we employ, is accomplished much more artistically by nature, that is, as I said, by artistically working fire, which is the master of the other arts.
This divine fire, or aether, is the basis for all activity in the Universe, operating on otherwise passive matter which neither increases not diminishes itself. The primary substance in the Universe comes from fire, passes through the stage of air, and then becomes water: the thicker portion becoming earth, and the thinner portion becoming air again, and then rarifying back into fire. Individual souls are part of the same fire as the world-soul of the Universe. Following Heraclitus, Zeno adopted the view that the Universe underwent regular cycles of formation and destruction.
The Nature of the Universe is such that it accomplishes what is right and prevents the opposite, and is identified with unconditional Fate, while allowing it the free-will attributed to it.
Zeno deviated from the Cynics in saying that things which are morally indifferent could nevertheless have value to us. Things have a relative value in proportion to how they aid the natural instinct for self-preservation. That which is to be preferred is a "fitting action" (kathêkon), a designation which Zeno first introduced. Self-preservation, and the things which contribute towards it, has only a conditional value; it does not aid happiness, which depends only on moral actions.
Just as Virtue can only exist within the dominion of Reason, so Vice can only exist with the rejection of Reason. Virtue is absolutely opposed to Vice, the two cannot exist in the same thing together, and cannot be increased or decreased; no one moral action is more virtuous than another. All actions are either good or bad, since impulses and desires rest upon free consent, and hence even passive mental states or emotions which are not guided by Reason are immoral, and produce immoral actions. Zeno distinguished four negative emotions: desire, fear, pleasure and pain (epithumia, phobos, hêdonê, lupê), and he was probably responsible for distinguishing the three corresponding positive emotions: will, caution, and joy (boulêsis, eulabeia, chara), with no corresponding rational equivalent for pain. All errors must be rooted out, not merely set aside, and replaced with right Reason.
The most famous of these works was Zeno's Republic, a work written in conscious imitation of (or opposition to) Plato. Although it has not survived, more is known about it than any of his other works. It outlined Zeno's vision of the ideal Stoic society built on egaliterian principles.