Philosophy

20th-Century Philosophy: Movements, Methods, and Influence 20th-century philosophy An overview of major trends, methods, and figures in philosophy during the twentieth century, including analytic and continental traditions and their lasting impact.

4 Maccabees: Greek treatise on reason, martyrdom, and Hellenistic Jewish ethics 4 Maccabees Ancient Greek treatise that praises reason over passion using Maccabean martyr stories. Likely composed in the 1st–2nd century CE; found in some Septuagint traditions and the Georg…

Abduction (logic): inference to the best explanation Abduction (logic) Abduction is the form of reasoning that generates plausible hypotheses to account for observations. It proposes likely explanations but does not guarantee truth; hypotheses require…

Absurdism: philosophy of the human search for meaning Absurdism Absurdism is a philosophical position about the conflict between humans' search for meaning and the universe's indifference. It influenced literature, theatre, and modern existenti…

Action theory (philosophy) Action theory Branch of philosophy examining intentional action, agency, intentions, reasons and causation—how mental states produce bodily movements and how responsibility is assigned.

Adam and Steve: origin, use, and cultural responses to a slogan Adam and Steve Overview of the phrase “Adam and Steve”: its origins as a conservative Christian slogan, historical use in public debate, and how artists and activists have responded and reinterpr…

Adi Shankara: Founder of Advaita Vedanta and Classical Indian Philosopher Adi Shankara 8th-century Indian philosopher and theologian credited with consolidating Advaita Vedanta, writing key commentaries, founding four monastic centers, and shaping later Hindu thought…

Adolf Grünbaum — Philosopher of Science and Critic of Psychoanalysis Adolf Grünbaum German-American philosopher Adolf Grünbaum (1923–2018) was influential in philosophy of science and philosophy of physics and is best known for rigorous critiques of psychoanalysis…

Advaita Vedanta Advaita Vedanta is a non-dual school within the Hindu tradition that teaches the essential unity of the individual self (Atman) and ultimate reality (Brahman), developed and system…

Aesthetics Aesthetics is the philosophical study of art, beauty, and sensory experience, examining why things are found pleasing or meaningful and how judgments of taste and value are formed.

Age of Enlightenment: Origins, Core Ideas, and Lasting Influence Age of Enlightenment An overview of the 18th-century Enlightenment: its central ideas, major figures and works, historical origins, political and cultural impacts, and how it is distinguished from rela…

Agnosticism Agnosticism is the position that the truth about the existence of deities is unknown or unknowable; it covers several stances on knowledge, belief and the limits of evidence.

Agorism: voluntary free-market anarchism and counter-economic tactics Agorism Agorism is a free‑market anarchist philosophy advocating voluntary exchange and peaceful undermining of state power through counter‑economic activity in informal markets.

Al-Kindi: Arab Philosopher and Polymath of the Early Abbasid Era Al-Kindi Al-Kindi (c. 801–873) was an Arab philosopher and polymath whose work in philosophy, mathematics, optics, music and translation helped shape early Islamic science and preserve Hell…

Alasdair MacIntyre: Philosopher of Virtue, Tradition and Moral Inquiry Alasdair MacIntyre Scottish philosopher Alasdair MacIntyre is best known for reviving Aristotelian virtue ethics and critiquing modern moral theory, influencing debates in ethics, politics, and theol…

Alchemy: history, aims, practices, symbolism and legacy Alchemy An accessible overview of alchemy: its goals, methods, symbolic language, historical development across cultures, and its influence on modern chemistry and thought.

Alea iacta est: the Latin phrase 'the die has been cast' — meaning and history Alea iacta est Latin phrase attributed to Julius Caesar during the 49 BC crossing of the Rubicon; signifies an irreversible decision. Overview, origins, linguistic notes, and modern uses.

Alexandre Koyré: Historian and Philosopher of Science Alexandre Koyré Alexandre Koyré (1892–1964) was a Russian-born French historian and philosopher of science who emphasized conceptual and metaphysical shifts in the Scientific Revolution and influe…

Alternative: choice, logic, and cultural meanings Alternative Overview of 'alternative' as a choice concept, its role in logic and mathematics, decision-making implications, and cultural uses across science, policy, and the arts.

Altruism: concepts, origins, forms, and debates Altruism Altruism is concern for others' welfare expressed through actions that benefit others, often at a cost to oneself. This article explains types, history, biological and philosophica…

Ambiguity: meanings, types, uses and how it differs from vagueness Ambiguity Ambiguity occurs when a word, sentence, or situation admits more than one interpretation. This article explains types, examples, history, practical effects and how ambiguity contra…

Analogy: forms, reasoning, and practical uses Analogy An analogy compares two things by highlighting shared features to explain, reason, or generate hypotheses. This article outlines types, cognitive role, historical perspectives, app…

Analytic philosophy: origins, methods, and influence Analytic philosophy Analytic philosophy is a major modern tradition emphasizing clarity, logical argument, and philosophy of language. This article outlines its features, history, uses, and key figure…

Anarcho-primitivism Anarcho-primitivism is a political and philosophical critique of civilization and technology that advocates dismantling industrial society in favor of decentralized, non-hierarchic…

Anaximander: Early Greek Natural Philosopher of Miletus Anaximander Anaximander (c.610–c.546 BCE) was a Pre-Socratic thinker from Miletus who proposed the apeiron as the originating principle, made early cosmological and biological hypotheses, and…

Ancient Greek philosophy: origins, major thinkers, and lasting legacy Ancient Greek philosophy Comprehensive overview of philosophical thought in ancient Greece: origins, main schools and figures, methods, key texts, and its influence on later cultures, science, and ethics.

Ancient philosophy: traditions, themes, and legacy Ancient philosophy Survey of philosophical traditions from the ancient world, their central themes, historical context including the Axial Age, and their continuing influence on ethics, science, and…

André Glucksmann: French philosopher, writer and public intellectual André Glucksmann André Glucksmann (1937–2015) was a French philosopher and polemicist associated with the late-20th-century 'new philosophers'. He critiqued totalitarianism, defended human rights a…

Anonymity: meaning, history, uses, and ethical considerations Anonymity Anonymity is the condition of being unnamed or unidentifiable. This article explains its meaning, origins, common forms, practical uses, and legal and ethical issues surrounding an…

Anthropic principle Philosophical and scientific idea that observations of the universe are constrained by the necessity that observers exist; includes weak/strong forms and influence on cosmology and…

Anti-fan: definition, behavior, history and social impact Anti-fan An anti-fan opposes a person, idea, or group and organizes criticism or hostility. This article explains typical behaviors, online and offline activity, historical development, imp…

Antonym — Word with Opposite Meaning Antonym An antonym is a word that expresses a meaning opposite to another. This article explains types, formation, history, examples, and their role in language, lexicography, and computin…

Appeal to emotion (argumentum ad passiones) Appeal to emotion A persuasive strategy that relies on stirring feelings instead of presenting logical reasons; a fallacy when emotion substitutes for evidence, though emotion can play a legitimate…

Appeal to Popularity (Argumentum ad Populum) Appeal to popularity A logical fallacy that treats widespread belief or practice as proof of truth. Explains structure, examples, history, why popularity is not evidence, and how to respond to it.

Appeal to tradition (argumentum ad antiquitatem) Appeal to tradition A logical fallacy that treats longevity or custom as proof of correctness; commonly appears in rhetoric, politics, and everyday justification of practices without independent evide…

Apples and Oranges (idiom): Meaning, Use, and Cautions Apples and oranges A concise guide to the idiom 'apples and oranges': its sense as a warning against improper comparisons, origins and equivalents, examples of use, and advice for fair comparison.

Approval Approval is a formal or informal expression that something meets a standard, gains consent or endorsement, or is authorized; it appears in social, legal, organizational, regulatory…

Aranyaka — Vedic 'forest' texts of ritual interpretation and philosophy Aranyaka Aranyakas are Vedic texts associated with forest-dwelling students and hermits that explain ritual practice symbolically, bridge Brahmanas and Upanishads, and helped shape later Hi…

Argument (reasoning and persuasion) Argument A structured set of reasons presented to support a claim or conclusion, used in logic, rhetoric, law, science and everyday decision-making.

Argument from Authority (Appeal to Authority) Argument from authority An explanation of the argument from authority: definitions, when it is reasonable or fallacious, historical context, common uses, and practical guidance for evaluating appeals to a…

Argument from design (teleological argument) Argument from design Philosophical claim that order and apparent purpose in nature indicate a designer; includes historical forms, key features, criticisms, and modern variants such as the fine‑tuning…

Argument from False Premises An overview of arguments based on false premises: definition, logical status, common examples, how they mislead, and methods for identifying and responding to them.

Argument from Ignorance (argumentum ad ignorantiam) Argument from ignorance A logical fallacy that treats lack of evidence for a claim as proof that the claim is true or false, often by shifting the burden of proof or forcing a false dichotomy.

Argument from Inconsistent Revelations A philosophical challenge arguing that mutually contradictory religious revelations make at least some divine claims unlikely; outlines the argument, examples, history, and common…

Argument from Nonbelief (Divine Hiddenness) Argument from nonbelief Philosophical challenge that argues the absence of clear divine revelation (reasonable nonbelief) counts against the existence of a loving, omnipotent deity; includes variants, obj…

Argumentum ad lazarum (appeal to poverty) Argumentum ad lazarum Argumentum ad lazarum, or appeal to poverty, is the informal fallacy of treating a claim as true or morally superior because its proponent is poor, or false because they are wealth…

Aristotle (384–322 BC) Aristotle Aristotle, Greek philosopher (384–322 BC), student of Plato and tutor to Alexander, shaped logic, metaphysics, ethics, politics and natural science; founder of the Peripatetic scho…

Arrogance: Definition, Causes, Effects, and Distinctions Arrogance Arrogance—often called hubris—is an inflated sense of self-importance and superiority. This article explains its traits, origins, social and psychological effects, differences from…