Thinkers

Abelardo (Peter Abelard) The most brilliant and controversial intellectual of the 12th century. Also famous for his tragic love affair with Heloise (castrated by order of her uncle). He proposed conceptualism in the dispute over universals and introduced dialectical reason into theology. “I understand in order to believe” — reason must examine before accepting by faith (an inversion of Anselm of Canterbury). Key Concepts Conceptualism (universalia post rem): universals are abstract concepts in the mind, neither real things separate from particulars (Plato) nor mere names (Roscellinus) Sic et Non: dialectical method — 158 theological questions answered with contradictory authorities; reason must resolve the contradiction Morality of intention: the act is neutral; good/evil resides in conscious intention Distinction: understanding (reason + faith) vs. comprehension (exclusive gift of God) Influenced by Anselm of Canterbury (criticizes exaggerated realism) Boethius — Aristotelian logic Influenced Thomas Aquinas — scholastic method of questions and solutions; ethics of intention Modern ethics of conscience and intention Works Sic et Non; Ethics or Know Thyself; Story of My Misfortunes (Historia Calamitatum). ...

Achille Mbembe Joseph-Achille Mbembe was born in 1957 in Otélé, Cameroon. He trained in history and philosophy at the Sorbonne (Paris I) and received his doctorate from the École des Hautes Études en Sciences Sociales (EHESS). He is currently a senior professor at the Wits Institute for Social and Economic Research (WISER) at the University of the Witwatersrand, Johannesburg, South Africa. Mbembe is considered one of the most influential African intellectuals today, with work that articulates African history, postcolonial theory, political philosophy, and cultural criticism. He writes in French; his principal works have been translated into English, Portuguese, German, and other languages. ...

Adam Smith Scottish moral philosopher and economist, considered the father of modern political economy. A central figure of the Scottish Enlightenment and close friend of Hume. His work combines sentiment-based ethics with market theory. Key Concepts Invisible hand: individuals’ self-interest, channeled through the market, generates collective benefit without central planning — a metaphor for the spontaneous order of the price system Division of labor: specialization of tasks multiplies productivity; the classic example of the pin factory Labor theory of value: the value of commodities ultimately derives from the labor embodied in their production Moral sympathy: the foundation of ethics — the capacity to put oneself in another’s position and evaluate actions from the perspective of an “impartial spectator” Impartial spectator: an imaginary figure representing balanced moral judgment, detached from self-interest Critique of mercantilism: a nation’s wealth is not the accumulation of precious metals, but its productive capacity and free exchange Free market and laissez-faire: defense of competition and criticism of monopolies, corporate privileges, and arbitrary state interventions Influenced by Hume — moral sentimentalism and skepticism about state intervention Francis Hutcheson — ethics of moral sense (his professor at Glasgow) Locke and Montesquieu — liberal political theories Mandeville — paradox of private vices / public benefits Influenced Ricardo and Mill — classical economics Marx — inherited (and critiqued) the labor theory of value Bentham — utilitarianism and calculation of collective well-being Modern economic liberalism and neoliberalism (Hayek, Friedman) Works The Theory of Moral Sentiments (1759); The Wealth of Nations (1776). ...

Adi Shankara Note on dating: The dates of Ādi Śaṅkara (also spelled Shankara; honorifically Śaṅkarācārya, “the teacher Śaṅkara”) are disputed. Tradition places him at 788–820 CE, but many modern scholars prefer an earlier dating, around c. 700–750 CE. His biography became interwoven with hagiographical material, so that many episodes of his life belong more to legend than to verifiable historical record. Śaṅkara is the most influential systematizer of Advaita Vedānta, the “non-dualist” current of Hindu philosophy. His work consists chiefly of rigorous commentaries on the canonical texts, in which he defends a metaphysics where the multiplicity of the world is ultimately reducible to a single reality. His influence on later Indian thought — and on the Western reception of Hinduism — is immense. ...

Al-Farabi Abū Naṣr Muḥammad ibn Muḥammad al-Fārābī (c. 872–c. 950) was one of the greatest philosophers of the medieval Islamic world, called by the tradition “the Second Teacher” (al-Muʿallim al-Thānī) — the first being Aristotle. Born in the region of Farab (present-day Kazakhstan/Uzbekistan), he worked principally in Baghdad and Aleppo under the patronage of the Hamdanid court. His work spans logic, political philosophy, metaphysics, philosophy of music, and theory of the sciences. ...

Alasdair MacIntyre Alasdair MacIntyre (1929–2025) was a Scottish-American moral philosopher, the author of one of the most influential works of twentieth-century moral philosophy, After Virtue (1981). His intellectual career was marked by a long pilgrimage: he set out from Marxism in his youth, passed through several positions, and ultimately converted to Catholicism and to Aristotelian Thomism in his maturity. He died in May 2025. MacIntyre diagnosed modern moral language as being in a state of grave disorder — composed of decontextualised fragments of traditions that have been lost — and argued that the “Enlightenment project” of providing an autonomous rational justification for morality had failed, clearing the way for emotivism. His proposal was the recovery of a virtue ethics of Aristotelian-Thomist roots, anchored in communal life and in traditions of enquiry. ...

Albert Camus Born in 1913 in French Algeria, into a poor settler (pied-noir) family, Albert Camus lost his father in infancy, in the First World War, and was raised by his illiterate, partly deaf mother in a humble district of Algiers. Tuberculosis would mark his entire life. A journalist and writer, he edited the newspaper Combat in the French Resistance and received the Nobel Prize in Literature in 1957, at the age of 44. Close to existentialism — though he rejected the label — he broke with Sartre over disagreements about revolutionary violence. He died in 1960 in a car accident, at the age of 46. ...

Albertus Magnus (Albert the Great) Dominican friar, Bishop of Regensburg, and Doctor Universalis. He was the teacher of Thomas Aquinas and the principal figure responsible for the systematic introduction of Aristotle into the medieval Latin world. Unlike other scholastics, Albert had a genuine interest in the natural sciences — botany, zoology, mineralogy, alchemy — combining empirical observation with philosophical reflection. Canonized and declared Doctor of the Church in 1931, he is the patron saint of natural scientists. ...

Amartya Sen Amartya Sen (b. 1933, Santiniketan, Bengal) is an Indian economist and philosopher whose work has dissolved the border between economics and ethics. He received the Nobel Memorial Prize in Economic Sciences in 1998 for his contributions to social choice theory and welfare economics. A professor at Harvard, Sen studied in Calcutta and Cambridge and served as master of Trinity College. Marked in his youth by the Bengal famine of 1943 — which killed millions and in which he lost a relative — he devoted himself to understanding the causes of poverty and deprivation and to rebuilding the normative foundations of economics. In intellectual partnership with the philosopher Martha Nussbaum, he developed the capability approach. He received the Bharat Ratna, India’s highest civilian honour, in 1999. ...

Anaxagoras Born in Clazomenae, in Ionia, around 500 BCE, Anaxagoras was the first philosopher to bring the Ionian tradition to Athens, where he lived for some thirty years and became a friend and adviser of the statesman Pericles. His intellectual boldness cost him dearly: accused of impiety for holding that the Sun was not a god but an incandescent stone, he was put on trial and had to leave the city, taking refuge in Lampsacus. ...

Anaximander A fellow citizen and disciple of Thales of Miletus, Anaximander (c. 610–546 BCE) was one of the boldest minds of the Milesian school and perhaps the first thinker to write a prose treatise on nature. Tradition credits him with the pioneering use of the term arché (“principle”), as well as remarkable achievements: drawing the first map of the inhabited world and introducing the gnomon (sundial) into Greece. Dissatisfied with Thales’s water, Anaximander proposed as the principle the apeiron — the boundless, indeterminate, and imperishable. No particular element could give rise to all the others without being consumed by them; only something indefinite and inexhaustible could be the eternal source of everything. From the apeiron, eternal and divine, the opposites (hot and cold, wet and dry) separate out, and from this separation worlds are born — which, in due time, return to it. The only surviving verbatim fragment, transmitted by Simplicius, speaks of this cosmology in moral terms: things “pay one another penalty and retribution for their injustice, according to the order of time.” ...

Anaxímenes The third great name of the Milesian school, Anaximenes (c. 585–525 BCE) was a disciple of Anaximander. At first glance he took a step back, rejecting his master’s indeterminate apeiron and returning to a concrete element as the principle: air (aēr). But his choice carried a decisive advantage — air, being determinate, allowed him to explain how the single principle transforms into all things, something that neither Thales’s water nor the apeiron explained clearly. ...

Anselm of Canterbury Born in Aosta, in the Alps, in 1033, Anselm entered the famous Benedictine monastery of Bec, in Normandy, where he became an admired master, and later became Archbishop of Canterbury, amid harsh conflicts with the English kings over the authority of the Church. He is called “the father of Scholasticism” for having inaugurated the systematic effort to use reason to penetrate the contents of faith. His motto sums up the whole medieval program: “fides quaerens intellectum” — faith seeking understanding. In the Proslogion he radicalizes it: “I do not seek to understand in order to believe, but I believe in order to understand” — a formula that gathers up the “crede ut intelligas” of Saint Augustine. ...

Aristotle Born in Stagira, in Macedonia, around 384 BCE, the son of Nicomachus — physician to the Macedonian court — Aristotle entered Plato’s Academy at the age of seventeen, where he remained for some twenty years, until his master’s death. He later tutored Alexander the Great and, in 335 BCE, founded the Lyceum in Athens, a school whose members became known as Peripatetics (from their habit of discussing while walking). With Alexander’s death and the wave of anti-Macedonian feeling, he left Athens in 323 BCE — so that the city, according to ancient tradition, “might not sin twice against philosophy” — and died the following year in Chalcis. The body of texts we have inherited from him is the largest and most systematic of antiquity, spanning logic, physics, biology, psychology, metaphysics, ethics, politics, rhetoric, and poetics. ...

Arthur Schopenhauer Born in Danzig in 1788, into a wealthy merchant family, Arthur Schopenhauer was able to devote himself to philosophy with financial independence. He earned his doctorate with On the Fourfold Root of the Principle of Sufficient Reason (1813) and at thirty published his major work, The World as Will and Representation (1818) — which, however, was almost entirely ignored for decades. Hostile to the then-dominant Hegel, he even scheduled his lectures at the same hour as his rival’s in Berlin, to no audience. Recognition came only at the end of his life, in the 1850s. He was also the first major Western philosopher to engage seriously with Indian thought (the Upanishads and Buddhism). ...

Auguste Comte French philosopher; founder of positivism and father of sociology as a scientific discipline. Disciple of Saint-Simon; proposed to reorganize society on scientific bases following the dual revolution (French and industrial). Key Concepts Law of Three Stages: each science and each society passes through three historical stages: Theological: explanation by supernatural agents (fetishism → polytheism → monotheism) Metaphysical: explanation by forces and abstract essences Positive (scientific): explanation by observable and measurable laws — the only valid stage Positivism: only knowledge based on observable facts and verifiable relations is legitimate; rejection of metaphysics and theology as immature Hierarchy of Sciences: mathematics → astronomy → physics → chemistry → biology → sociology (the most complex and most recent) Sociology: positive science of society — Social Physics; divided into statics (order, structure) and dynamics (progress, change) Religion of Humanity: late phase — Comte proposed replacing God with Humanity as the object of worship, with rituals and positivist calendar (Positive Politics) Influenced by Saint-Simon — social reorganization through science and industrialism Condorcet — historical progress and human perfectibility Montesquieu — laws in social history French Enlightenment — reason and science Influenced Émile Durkheim — scientific sociology John Stuart Mill — methodology and positivism (with reservations) Twentieth-century logical positivism (distant reading) Brazil — the motto “Order and Progress” on the flag is directly Comtean Works Course in Positive Philosophy (6 vols., 1830–1842); Discourse on the Positive Spirit (1844); System of Positive Politics (4 vols., 1851–1854). ...

Averroes (Ibn Rushd) Abu al-Walid Muhammad Ibn Rushd, Latinized as Averroes, was born in Córdoba in 1126, at the height of the Islamic civilization of Al-Andalus. A judge (qadi), physician, and philosopher in the service of the Almohad caliphs, he became known in medieval Europe simply as “the Commentator”: his meticulous commentaries on the work of Aristotle were, for centuries, the principal gateway to Aristotelian thought for Latins and Jews. He fell from favor at the end of his life, when his works were condemned, and died in Marrakesh in 1198. ...

Avicenna (Ibn Sīnā) Born in 980 near Bukhara, in Persian-speaking Central Asia, Abu Ali Ibn Sīnā — Latinized as Avicenna — was a prodigy: it is said that by the age of eighteen he had already mastered the medicine of his time. He led a turbulent life, amid courts, imprisonments, and posts as vizier, yet left more than two hundred works. His Canon of Medicine was the principal medical textbook in the West for centuries, and his Book of Healing is a vast philosophical encyclopedia. He is the greatest philosopher of the medieval Islamic world, and his name is bound to a distinction that would transform Western metaphysics. ...

Baruch Spinoza (Benedict of Spinoza) Born in Amsterdam in 1632, into a family of Sephardic Jews of Portuguese origin who had fled the Inquisition, Baruch Spinoza received a rabbinic education, but his ideas soon put him on a collision course with the community: in 1656 he was subjected to a herem (excommunication) of rare severity. He declined chairs and honors to preserve his independence of thought and supported himself humbly by grinding optical lenses. He died young, in 1677, and his principal works — among them the Ethics — were published only after his death. He is regarded as the most radical of the seventeenth-century rationalists. ...

Bernard Williams Bernard Williams was one of the most important British moral philosophers of the twentieth century and one of the most penetrating critics of the ambition to ground ethics in a single, impersonal theoretical system. He taught at Cambridge, Berkeley, and Oxford. Against both utilitarianism and Kantianism, Williams insisted on the irreducible complexity of moral life, on the importance of the first-person perspective, of personal commitments and emotions, and on the inability of grand theories to capture everything that matters ethically. His writing combines classical learning, psychological sensitivity, and an elegant distrust of philosophical oversimplification. ...