Skepticism

Imagine dropping a stone a thousand times, and a thousand times it falls. You are utterly certain it will fall on the thousand-and-first. But pause and ask: what, exactly, justifies that certainty? You have never seen the “necessity” of the stone’s falling — you have only seen stones falling. The leap from what has happened to what will happen seems obvious, yet when we examine it, no logical proof holds it up. This small abyss, opened by David Hume in the eighteenth century, has never quite been closed. It swallows causation, induction, the self, and much of metaphysics — and it is the best place to start understanding why Hume is perhaps the most unsettling of modern philosophers. ...

Michel Eyquem de Montaigne (1533–1592) is one of those rare thinkers whose influence is measured not by the construction of a philosophical system but by the invention of a form. By creating the essay — a word he coined himself, from the French essai, meaning attempt or trial — he inaugurated a way of thinking that refuses any claim to final truth and makes the thinking subject both the object and the instrument of inquiry. His Essais, published between 1580 and 1595, remain among the most widely read texts in Western literature, and their philosophical significance has only grown with time. ...

Few distinctions have been as decisive for the history of Western philosophy as the one that separates doxa (δόξα, opinion) from episteme (ἐπιστήμη, knowledge). Since the Pre-Socratics, the effort to move beyond the plane of appearances toward well-grounded understanding has constituted the central impulse of philosophical inquiry. Doxa designates the unjustified judgment, the belief that rests on sensory appearances or social convention; episteme, by contrast, aspires to justified truth — to knowledge sustained by necessary reasons. ...

Few philosophical gestures are as radical — and as productive — as the deliberate decision to withhold judgment. Epoché (ἐποχή), the suspension of assent, runs through the history of Western philosophy like a thread connecting ancient skepticism to contemporary phenomenology, passing through Cartesian doubt and British empiricism along the way. Born as a practice of life among the Pyrrhonian skeptics, who sought in it the tranquility of the soul, epoché was reclaimed twenty-three centuries later by Edmund Husserl as the founding method of phenomenology — the path to “the things themselves.” ...

Blaise Pascal French mathematician, physicist and philosopher. A precocious genius (invented the mechanical calculator at age 19); converted to Jansenism after his “night of fire” (1654). His philosophy is an existential wager and a confrontation with the reason of the libertines. Key Concepts The wager (Pascal’s wager): pragmatic argument about belief in God. If God exists and you believe — infinite gain; if he does not exist and you believe — finite loss. If he exists and you do not believe — infinite loss. Prudent reason bets on God — even without rational proof “The heart has its reasons which reason knows nothing of”: there is an order of the heart — intuition, love, feeling — irreducible to the demonstrative logic of Descartes Misery and grandeur of man: man is a roseau pensant (thinking reed) — fragile as nature, but his greatness lies in thinking; more noble than the universe because he knows that he dies The two infinities: between the great infinity (cosmos) and the small infinity (atom), man stands in the middle — without firm foundation either in sciences or in metaphysics Diversion (divertissement): man flees from confrontation with himself through agitation — boredom reveals the human misery that diversion hides. Critique of social superficiality Critique of Cartesianism: Descartes’ method is useful in the sciences, but illusory as a foundation for faith or morality; “Descartes useless and uncertain” Jansenism: Catholic current that emphasized the irresistible grace of Augustine; Pascal defended Port-Royal in the Provincial Letters against the Jesuits Influenced by Saint Augustine — grace, sin, predestination Montaigne — skepticism, human misery (point of departure and adversary) Descartes — rationalism (critique) Ancient Pyrrhonism — skepticism as apologetic weapon Influenced Kierkegaard — wager, paradox, subjectivity of faith Existentialism — anguish and human condition Modern Christian apologetics Decision theory and game theory (wager as precursor) Works Provincial Letters (1656–1657); Pensées (posthumous, 1670 — fragments of an unfinished apologetic); Treatise on the Arithmetic of the Triangle (1654). ...

Carneades of Cyrene Carneades of Cyrene (c. 214/213–129/128 BC) was the most prominent head (scholarch) of the New Academy in Athens and the central figure of Academic Skepticism. Born in Cyrene in North Africa, he emigrated to Athens and remained there for his entire philosophical career, leading an Academy that had taken a radically skeptical turn since Arcesilaus. Carneades left no writings — an apparently deliberate choice consistent with his position that no thesis should be held dogmatically. His thought reaches us primarily through three mediations: his disciple Clitomachus of Carthage, who recorded his lectures in more than four hundred books; Cicero, who in the Academica and De Natura Deorum presents and debates Academic positions; and Sextus Empiricus, who preserved several of his arguments against the Stoics. ...

David Hume A central figure of the Scottish Enlightenment, David Hume was born in Edinburgh in 1711. While still very young he published his Treatise of Human Nature (1739–40), a work that, in his own words, “fell dead-born from the press” and would be recognized only much later. His reputation as a skeptic in matters of religion cost him the university chairs he sought; he made his living as a librarian, a diplomatic secretary, and above all as a highly successful essayist and historian. A man of serene and amiable temperament — “le bon David” — he died in 1776, facing death with the tranquility of a sage. ...

Gorgias A native of Leontini, in Sicily, Gorgias lived, according to tradition, more than a hundred years (c. 483–375 BCE). He came to Athens in 427 BCE as ambassador of his city and dazzled the Athenians with a new oratorical style, full of figures and rhythms — becoming the most celebrated and highly paid master of rhetoric of Antiquity. Alongside Protagoras, he is the great figure of the first generation of the Sophists. ...

Michel de Montaigne Born in 1533 at his family’s château in the Périgord, Michel de Montaigne received a refined humanist education — raised to speak Latin as his first language. He served as a magistrate in the Parlement of Bordeaux, where he formed a profound friendship with Étienne de La Boétie, whose death would mark him forever. Around 1571 he withdrew to the tower of his château, surrounded by books, and there, amid the bloody Wars of Religion, he began to write a work of an entirely new genre: the Essays. He is one of the fathers of modern thought and the inventor of the essay as a literary and philosophical form. ...

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. A native of Elis in the Peloponnese, Pyrrho lived around 365 to 270 B.C. and worked during a period shaped by the dissolution of the classical city-state and the rise of Hellenistic cosmopolitanism. In this context of political instability and cultural diversity, the question of how to achieve happiness (eudaimonia) acquired renewed urgency. Pyrrho’s answer was radical: happiness does not depend on knowing the ultimate truth about things, but on recognizing that such truth is beyond our reach. In his view, things are equally indeterminable, ungraspable, and undecidable (adiaphora, astathmêta, anepíkrita); faced with this situation, the wise course is epoché — suspension of judgment — rather than hasty assertion. His principal disciple, Timon of Phlius, preserved his ideas in verse form, enabling Pyrrhonism to reach later generations. ...

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. Sextus Empiricus probably lived and wrote between the second and third centuries CE, at a time when Pyrrhonian skepticism had been revived by Aenesidemus roughly two centuries after Pyrrho of Elis. The epithet “Empiricus” signals his affiliation with the Empiric school of medicine, which rejected hidden causal theories and confined itself to observable experience — a methodological stance that directly mirrors his philosophy. Although almost nothing is known of his biography, his textual output is exceptional: the Outlines of Pyrrhonism offers a pedagogical presentation of the skeptical method in three books, while the eleven books of Adversus Mathematicos systematically dismantle the knowledge-claims of grammarians, rhetoricians, geometers, arithmeticians, astrologers, musicians, logicians, natural philosophers, and ethicists. This breadth shows that Sextus’s skepticism was not intellectual nihilism, but a rigorous philosophical program: by demonstrating that for every dogmatic assertion there is a counter-argument of equal force (isostheneia), he aims to induce suspension of judgment and, as a consequence, peace of mind. ...

Xenophanes of Colophon Itinerant Greek poet-philosopher, born in Colophon, in Ionia (the western coast of Asia Minor), around 570 BCE. When the Persian conquest of Ionia began in the mid-sixth century BCE, Xenophanes left his native city and spent the rest of his life wandering the Greek world, residing for periods in Zancle and Catana in Sicily and, according to tradition, in Elea in southern Italy. He lived to an exceptionally advanced age — ancient sources suggest he surpassed ninety years — and his entire output survives only in fragments preserved by later authors such as Sextus Empiricus, Simplicius, and Athenaeus. ...