Hellenistic Philosophy

Among all the philosophical schools of Antiquity, none exercised so prolonged and so diverse an influence as Stoicism. Founded in Athens around 300 BCE by Zeno of Citium, Stoicism spanned five centuries, shaped Roman law, infiltrated early Christianity, and resurfaced powerfully in the Renaissance, the Enlightenment, and — more recently — in cognitive-behavioral therapy and philosophical self-help movements. The reason for this longevity is simple: Stoicism offers a coherent and practicable answer to the most urgent question of human existence — how to live well in a world we do not control. ...

Chrysippus of Soli (c. 280–c. 207 BCE) was the third scholarch (head) of the Stoic school in Athens and is considered, alongside Zeno of Citium, the second founder of Stoicism. While Zeno founded the school and established its fundamental theses, it was Chrysippus who systematically elaborated Stoic logic, physics, and ethics, producing a monumental body of work that ancient tradition estimated at over 700 titles — almost all now lost. What we know of his thought comes from secondary sources: Diogenes Laërtius, Plutarch, Cicero, Sextus Empiricus, and Epictetus. ...

Cicero Roman philosopher, orator, and statesman. The most important figure in transmitting Greek philosophy to the Latin world. His eclecticism synthesized Epicureanism, Stoicism, and the skepticism of the New Academy. He coined much of the Latin philosophical vocabulary — essentia, qualitas, moralis — that shaped all subsequent Western philosophy. Key Concepts Natural law: there is a universal moral law, grounded in reason, that transcends the positive laws of each people — the foundation of Western natural law theory Res publica: the republic as “the people’s affair” (res populi); the state is only legitimate when it serves the common good and respects the law Duty (officium): ethical life consists in fulfilling duties arising from reason, human social nature, and the roles each person occupies — systematized in De Officiis Academic probabilism: influenced by the skepticism of the New Academy, he argues that in the absence of certainty we should act according to what seems most probable (verisimile) Humanitas: the ideal of full human formation combining philosophy, rhetoric, and civic virtue; the Roman equivalent of the Greek paideia Highest good (summum bonum): debate among schools — for Stoics, virtue; for Epicureans, pleasure. Cicero leans toward Stoicism but presents arguments from all schools Influenced by Plato and Aristotle — politics, ethics, theory of knowledge Zeno of Citium — Stoicism (cosmopolitanism, natural law, duty) Epicurus — addressed critically Carneades — skepticism of the New Academy Influenced Augustine and all medieval philosophy — Latin vocabulary and natural law Thomas Aquinas — natural law theory Machiavelli, Montesquieu, Rousseau — republican theory Locke and Kant — natural rights and moral duty Renaissance humanism — ideal of humanitas Works On the Republic (De Re Publica, 54 BC); On the Laws (De Legibus, 52 BC); Tusculan Disputations (Tusculanae Disputationes, 45 BC); On Duties (De Officiis, 44 BC); On the Nature of the Gods (De Natura Deorum, 45 BC). ...

Diogenes of Sinope “Diogenes the dog” (kynikós) — refoundaer and principal figure of Cynicism. He lived in a barrel in Athens, reduced his needs to a minimum, and despised all social convention. He said he sought “an honest man” walking with a lantern lit in broad daylight. When Alexander the Great offered to grant him any desire, he asked only that he step out of his sunlight. He embodied radical anticultural philosophy: virtue requires total self-sufficiency, not abstract philosophy. ...

Epictetus Phrygian ex-slave; the Stoic who most lived what he preached. His central distinction structures all Stoic ethics: what depends on us (eph’ hêmin: thoughts, impulses, judgments, desires) vs. what does not depend on us (ouk eph’ hêmin: body, fame, wealth, health). Inner freedom is absolute and cannot be taken by any master. “Bear and forbear” (anékhou kai apékhou). Key Concepts Dichotomy of control: what depends on us vs. what does not depend on us Inner freedom as the only true freedom Prohairesis: the faculty of rational choice — sole complete good Philosophy as a way of life, not abstract theory Influenced by Zeno of Citium — Stoic doctrine Socrates — self-examination Influenced Marcus Aurelius — Meditations are notes of Stoic practice inspired by Epictetus Contemporary cognitive psychology (rational-emotive therapy by Ellis) Works He did not write. Arrian (disciple) recorded: Enchiridion (Manual); Discourses (8 books, 4 preserved). ...

Epicurus Born on the island of Samos around 341 BCE, Epicurus founded in Athens, in 307 BCE, the school known as the Garden (Kepos) — a community of friends that, remarkably for its time, welcomed women and slaves. He lived simply and in seclusion, and died around 270 BCE, facing with serenity the pains of a kidney ailment. His philosophy, heir to Socrates in the ideal of philosophy as an art of living, has a therapeutic aim: to free the human being from what disturbs their peace. ...

Lucretius (Titus Lucretius Carus) Roman poet and philosopher, author of De Rerum Natura (On the Nature of Things), the greatest philosophical poem of Antiquity. He systematized in Latin verse the physics and ethics of Epicurus, becoming the primary source for our knowledge of ancient Epicureanism. He defended atomism as an explanation of the universe, the mortality of the soul, and liberation from the fear of gods and death through rational understanding of nature. ...

Marcus Aurelius Marcus Aurelius Antoninus ruled Rome from 161 to 180 CE and is remembered as the last of the “Five Good Emperors” and as the most celebrated example of the ancient ideal of the philosopher-king. Adopted into the line of succession by Antoninus Pius, he received a careful education and turned early to Stoicism, above all through reading Epictetus, to whom he had been introduced by his teacher Junius Rusticus. His reign, far from peaceful, was beset by wars on the Danube frontier, by revolts, and by the devastating Antonine Plague — circumstances in which his philosophy proved less a doctrine than a discipline of inner survival. ...

Plotinus Born around 205 CE, probably in Roman Egypt, Plotinus studied for years in Alexandria under the enigmatic master Ammonius Saccas and later settled in Rome, where he founded a school and led a life of remarkable asceticism. His lessons were gathered and organized by his disciple Porphyry in the Enneads. He is the founder of Neoplatonism and the greatest philosopher of late antiquity, making Plato the starting point of one of the most grandiose metaphysics ever conceived. ...

Pyrrho Founder of Ancient Skepticism. Accompanied Alexander the Great to India and encountered ascetics who influenced his thought. Left no writings; lived coherently with epoché. Tranquility (ataraxia) arrives naturally when one suspends all judgment: since we cannot know whether something is good or bad, beautiful or ugly, there is no reason for disturbance. Key Concepts Epoché: suspension of all judgment Aphasia: refraining from making assertions about reality Ataraxia as a consequence of epoché Phenomenalism: only phenomena (appearances) are accessible Influenced by Democritus — relativity of perceptions Gorgias — radical skepticism Indian ascetics (gymnosophists) Influenced Timon of Phlius — disciple New Academy (Arcesilaus, Carneades) Sextus Empiricus — systematization of Pyrrhonism Montaigne, Descartes (method of doubt) Works None. Sources: Diogenes Laërtius, Lives, IX; Sextus Empiricus, Pyrrhonian Outlines. ...

Seneca Lucius Annaeus Seneca was born in Corduba, in Hispania, around 4 BCE, the son of Seneca the Elder, a renowned teacher of rhetoric. He was the most influential — and also the most controversial — of the Roman Stoics: a wealthy and powerful senator, he endured exile in Corsica under the emperor Claudius and, on his return to Rome, became tutor and later advisor to the young Nero, whom he sought to restrain in the early years of his reign. Accused of taking part in the Pisonian conspiracy, he was forced by Nero to take his own life in 65 CE — a death that, according to Tacitus’s account, he faced with the serenity his philosophy preached. ...

Sextus Empiricus Greek physician and philosopher, the principal systematizer of Pyrrhonian skepticism. His works are the most complete source on the ancient skeptical tradition founded by Pyrrho. While the dogmatists (Stoics, Epicureans, Platonists) claimed to reach definitive truth, Sextus defends the suspension of judgment (epoché) as the path to tranquility (ataraxia). His influence was decisive on modern philosophy, especially on Montaigne, Descartes, and Hume. Key Concepts Epoché (suspension of judgment): faced with equipollent arguments, the skeptic suspends assent — neither affirming nor denying Isostheneia (equipollence): equal strength of contrary arguments — for every argument in favor, there is one of equal force against Tropes (modes of suspension): systematization of skeptical arguments — 10 tropes of Aenesidemus (relativity of perceptions), 5 tropes of Agrippa (disagreement, infinite regress, relativity, hypothesis, circularity) Phenomenon (phainomenon): the skeptic accepts appearances as a practical guide to life, without affirming that they correspond to reality Practical criterion: the skeptic lives according to nature, customs, laws, and arts — without claiming absolute truth Anti-dogmatism: systematic critique of all philosophical schools that claim to know the ultimate nature of things Influenced by Pyrrho — founder of Pyrrhonian skepticism Aenesidemus — renewal of Pyrrhonism; 10 tropes Timon of Phlius — disciple of Pyrrho Influenced Montaigne — skepticism of the Essays (Apology for Raymond Sebond) Descartes — methodical doubt as a response to skepticism Hume — skepticism about causation and induction Pascal — limits of human reason Francisco Sanches — Quod nihil scitur (1581) Works Outlines of Pyrrhonism (Pyrrhōneioi Hypotypōseis, 3 books) — systematic exposition of the skeptical method; Against the Mathematicians (Adversus Mathematicos, 11 books) — refutation of dogmatic disciplines (grammar, rhetoric, geometry, arithmetic, astrology, music, logic, physics, ethics). ...

Zeno of Citium Founder of Stoicism. He taught at the Stoa Poikilê (Painted Porch) in Athens — hence the name of the school. After hearing the story of Socrates through the cynicism of Crates, he abandoned commerce to dedicate himself to philosophy. He taught that virtue is the only real good; everything else (wealth, health, fame) is indifferent (adiaphora). The universe is permeated by the divine Logos (rational fire) and each event occurs by rational necessity. ...