100 Fun Facts About Philosophy

Which Greek philosopher is associated with a question-and-answer method of inquiry?

In Plato's Theaetetus, Socrates compares his questioning to midwifery, drawing understanding out of his partners rather than putting it in.

In which of Plato's works does he present the Allegory of the Cave?

Republic sets the cave in Book VII: prisoners chained since childhood take shadows on a wall for reality, and would kill anyone who tried to drag them up into the daylight.

What Kantian concept says an action is moral if its maxim can be universalised without contradiction?

The Categorical Imperative rules out a false promise to repay a loan, in Kant's own example: if everyone made such promises, nobody would believe them and lending would stop.

Which 20th-century philosopher built his 1927 book Being and Time around the term 'Dasein'?

Martin Heidegger took Dasein, the ordinary German word for 'existence' that earlier philosophers had also used, and made it his name for the kind of being that humans alone have.

Which branch of philosophy is concerned with the nature of knowledge, its acquisition, and its limits?

Epistemology takes its name from the Greek episteme, 'knowledge'. Its questions go back to Plato, but the word itself is young: it was coined only in the mid-19th century.

'Cogito, ergo sum' ('I think, therefore I am') is a cornerstone of whose philosophy?

René Descartes first wrote it in French, 'je pense, donc je suis', in his 1637 Discourse on the Method; the famous Latin wording came later, in his Principles of Philosophy.

Which philosopher is best known for 'tabula rasa', the idea that we are born without innate mental content?

John Locke opened his Essay Concerning Human Understanding by attacking the belief in innate ideas, then pictured the newborn mind as 'white paper, void of all characters' for experience to write on.

Which Greek philosopher lived in a large jar and carried a lit lantern by day, 'looking for a man'?

Diogenes also mocked Plato's definition of man as a 'featherless biped': he plucked a chicken, carried it into the lecture room and announced, 'Here is Plato's man.'

Which ethical framework is often summarized by the phrase 'the greatest good for the greatest number'?

Utilitarianism counts every creature's pain and pleasure, which led its founder to argue that animals matter too: the question, he wrote, is not whether they can reason or talk but 'Can they suffer?'

Which philosophy founded by Zeno of Citium emphasises virtue, reason and harmony with nature?

Stoicism is named after a building: Zeno taught at the Stoa Poikile, the 'Painted Porch' in Athens, and his followers became known as the people of the porch.

Which thought experiment did English philosopher Philippa Foot introduce in a 1967 paper?

The trolley problem began as Foot's driver of a runaway tram who must choose between killing five people and killing one; the name came later, from the American philosopher Judith Jarvis Thomson.

Aristotle's view that each virtue lies between two extremes, like courage between cowardice and rashness, goes by what name?

The Golden Mean is no fixed midpoint for Aristotle: the food ration that suits a champion wrestler, he noted, is too much for a beginner, so the right amount depends on the person.

Which philosophical school is traditionally set against empiricism over where knowledge comes from?

Rationalism trusts reason over the senses and took mathematics as its model: one of its champions even wrote out his ethics as a chain of geometric proofs, with definitions, axioms and propositions.

Whose ship, repaired plank by plank in Athens, gave its name to a puzzle about identity?

Theseus's ship had its rotting timbers replaced until philosophers disputed whether it was the same vessel, Plutarch reports; a later twist asks about a second ship built from the discarded planks.

Which English philosopher set out social contract theory in his 1651 book Leviathan?

Thomas Hobbes argued in Leviathan for a strong sovereign to escape the 'state of nature', a 'war of all against all'.

The ancient Greek school of philosophy founded by Plato was known by what name?

The Academy met in an olive grove outside the walls of Athens that was linked to a legendary hero, Akademos; the grove's name has meant a place of learning ever since.

Which ancient Greek philosopher is considered the founder of Skepticism, advocating suspension of judgment?

Pyrrho of Elis wrote nothing himself. He is said to have travelled as far as India with a Greek army and met ascetics the Greeks called 'naked wise men', a meeting one ancient biographer credits for his philosophy.

Which English jurist and 'greatest happiness' theorist devised the 'felicific calculus'?

Jeremy Bentham applied his test of usefulness even to his own corpse: his will had his body dissected, then preserved and dressed as an 'auto-icon', which went to University College London in 1850.

Which philosopher developed historical materialism, the theory that economic conditions shape a society's laws, politics and ideas?

Karl Marx summed it up by turning a common assumption upside down: 'It is not the consciousness of men that determines their existence, but their social existence that determines their consciousness.'

Which Neoplatonist philosopher and mathematician was killed by an Alexandrian mob in 415 AD?

Hypatia advised the Roman prefect Orestes, and a rumour blamed her for his feud with Bishop Cyril; a mob led by a church reader named Peter dragged her from her carriage and killed her.

The 'Will to Power' is a central idea in the philosophy of which German thinker?

Friedrich Nietzsche only considered writing a book called The Will to Power; the volume published under that title in 1901, after his death, was assembled from his notes by his sister Elisabeth.

Which French existentialist wrote Being and Nothingness?

Jean-Paul Sartre later turned down the 1964 Nobel Prize in Literature, explaining that a writer should not allow himself to be turned into an institution.

Which 17th-century thinker described reality as made of simple substances called 'monads'?

Gottfried Leibniz set out his monads in the Monadology of 1714. He also developed calculus independently of Newton, and it was his notation that became the standard.

Which philosopher wrote 'Whereof one cannot speak, thereof one must be silent' in his Tractatus?

Ludwig Wittgenstein wrote the Tractatus as a soldier in the First World War; convinced it had solved every problem of philosophy, he gave away his fortune and went off to teach in a village school.

Which French philosopher wrote The Second Sex and explored the concept of 'the Other'?

Simone de Beauvoir's most quoted line comes from this book: 'One is not born, but rather becomes, a woman', a sentence credited with separating gender from biological sex.

'Power-knowledge' and 'discourse' are central ideas of which French philosopher?

Michel Foucault argued that power and knowledge feed each other: Discipline and Punish traces how prisons, schools and hospitals watch and examine people, then use what they learn to control them.

Which philosopher explored "the absurd" in his essay "The Myth of Sisyphus"?

Albert Camus's 1942 essay locates the absurd in the clash between our need for meaning and the 'unreasonable silence' of the universe, and concludes that we must imagine Sisyphus happy.

Which 19th-century philosopher, called the 'Father of Existentialism', emphasised individual choice and the 'leap of faith'?

Søren Kierkegaard published much of his work under pseudonyms such as Johannes Climacus and Victor Eremita, and spent his last years in a public feud with the Danish state church.

Which ancient Chinese philosopher is traditionally credited with founding Taoism?

Laozi, the legend goes, saw the Zhou dynasty in decline and was on his way out when the keeper of a pass asked him to write down his teachings first; the result was the Tao Te Ching.

Which collection of sayings, compiled by his followers, is the main record of the teachings of Confucius?

The Analects show Confucius claiming to invent nothing: he calls himself someone who 'transmits, but does not innovate', handing on the ways of earlier sages.

Which novelist-philosopher developed Objectivism, championing rational egoism and individual rights?

Ayn Rand was born Alisa Rosenbaum in St Petersburg, where the new Soviet state confiscated her father's pharmacy; she left for the United States in 1926 and made the individual the centre of her philosophy.

Which empiricist philosopher is known for his radical skepticism about causation and induction?

David Hume's problem of induction holds that any inference from past experience presupposes that the future will resemble the past, a presupposition experience itself can never justify.

Which idealist philosopher famously stated 'Esse est percipi' ('To be is to be perceived')?

George Berkeley, an Anglican bishop of Cloyne in Ireland, argued that material things exist only as perceived; the Californian city of Berkeley was named after him.

Logical Positivism was associated with which group of thinkers?

The Vienna Circle met around the philosopher Moritz Schlick until 1936, when a former student shot him dead on the steps of the University of Vienna; its members soon scattered into exile.

Which Enlightenment philosopher built his political theory on the 'general will' of the people?

Jean-Jacques Rousseau argued in The Social Contract (1762) that citizens forced to obey the general will are thereby made free, because collectively they are the authors of the law.

Which medieval philosopher fused Aristotle with Christian theology and offered five ways to prove God exists?

Thomas Aquinas never finished his great Summa: a few months before his death he abruptly stopped writing, saying that everything he had written now seemed 'like straw' to him.

Schopenhauer's principal work, published in 1818 and expanded in 1844, has what title?

The World as Will and Representation sees a blind, striving will behind everything. Its author later scheduled his Berlin lectures at the same hour as a famous rival's, and almost nobody came.

The 'dialectic' and 'Absolute Spirit' are central to which German idealist's philosophy?

G.W.F. Hegel finished his first major book in Jena in October 1806, as Napoleon's army arrived for the Battle of Jena; he wrote of seeing the emperor, 'this world-soul', riding out of the city.

Which philosopher introduced the 'veil of ignorance' in A Theory of Justice?

John Rawls argued that people choosing rules from behind the veil, not knowing whether they would end up rich or poor, would play safe and allow only inequalities that benefit the worst-off.

Which ancient Greek school taught that limiting desires and banishing fear bring tranquility ('ataraxia') and freedom from pain?

Epicureanism was plainer than the word 'epicurean' now suggests: at the Garden, Epicurus's school in Athens, the meals were simple and, unusually for the time, women and slaves were welcome.

Which early Greek thinker, often called the first philosopher, proposed water as the fundamental substance of the world?

Thales of Miletus held that water was the first principle and that the Earth floated on it; he is also credited with predicting the solar eclipse of 585 BC.

Which early Greek philosopher proposed the 'apeiron', the boundless, as the source of everything?

Anaximander also reasoned that the first humans must have grown inside fish-like creatures, because a helpless human infant could never have survived on its own.

Which ancient Greek philosopher of 'flux' is credited with 'No man ever steps in the same river twice'?

Heraclitus's surviving fragment says only that ever-different waters flow over those who step into the same rivers; the snappier line is Plato's paraphrase of him in the Cratylus.

Which early Greek philosopher argued against change, holding that true 'Being' is eternal and undivided?

Parmenides of Elea set out his 'way of truth' in a poem; his pupil Zeno is traditionally said to have devised his famous paradoxes of motion to defend it.

Protagoras's 'Man is the measure of all things' reflects his view on what aspect of knowledge?

Its subjective relativity is how Plato read the saying: if the wind feels cold to one person and warm to another, then it simply is cold for the one and warm for the other.

Gorgias, who argued that nothing exists, was one of which group of paid travelling teachers in ancient Greece?

The Sophists taught the art of persuasion. Gorgias went on to argue that even if something did exist it could not be known or communicated, a case some read as a parody of rival philosophers.

Which early Christian philosopher wrote Confessions and City of God?

Augustine of Hippo wrote City of God after the Visigoths sacked Rome in 410, to answer pagans who blamed the disaster on the empire's turn to Christianity.

Which Roman philosopher wrote The Consolation of Philosophy while imprisoned and awaiting execution?

Boethius had been one of the most senior officials of Theodoric, the Ostrogothic king of Italy, before a treason charge put him in a cell; his book was later put into English by both King Alfred and Chaucer.

Which medieval philosopher's ontological argument defines God as 'that than which no greater can be conceived'?

Anselm of Canterbury set it out in his Proslogion, written in 1077-78; a monk named Gaunilo replied 'on behalf of the fool' that the same logic would prove a perfect island exists.

Which 14th-century Franciscan is credited with the 'razor' favouring the hypothesis with fewest assumptions?

William of Ockham never wrote the Latin tag usually quoted, 'entities must not be multiplied beyond necessity'; his principle of parsimony was named 'Occam's razor' only centuries after his death.

Which household object did Bertrand Russell imagine orbiting the Sun to show where the burden of proof lies?

A teapot too small for any telescope was his example: nobody could disprove it, yet nobody would have to believe it. The burden of proof, Russell argued, lies with whoever makes the claim.

Philip II of Macedon invited Aristotle to tutor his thirteen-year-old son, which future conqueror?

Alexander the Great took his lessons at Mieza, on a royal estate near the Macedonian capital. Aristotle was no stranger at court: his father had been personal physician to an earlier Macedonian king.

Plato's dialogues Timaeus and Critias are the only original sources for the story of which sunken island?

Atlantis has no source older than Plato: every later mention of the island traces back to those two dialogues. He told the story as an allegory on the hubris of nations.

Which Roman emperor wrote the private notebooks now called Meditations while campaigning on the northern frontier?

Marcus Aurelius wrote them in Greek as reminders to himself, never as a book for readers. One section is headed as written 'in the country of the Quadi', by a river in what is now Slovakia.

Which Renaissance painter placed Plato and Aristotle at the centre of his Vatican fresco The School of Athens?

Raphael is believed to have given Plato the face of Leonardo da Vinci. Plato gestures up toward the vault while Aristotle reaches out level, a contrast many read as their two philosophies in one image.

Which Florentine diplomat advised in The Prince that it is far safer for a ruler to be feared than loved?

Niccolò Machiavelli added a limit that is often forgotten: a prince must never be feared to the point of hatred. The book reached print only in 1532, five years after his death.

Thomas Nagel's famous 1974 paper on consciousness asks what it is like to be which animal?

A bat suited his point because it is a mammal, so presumably conscious, yet it navigates by echolocation. We can imagine hanging upside down, Nagel argued, but not what that is like for the bat itself.

Which French writer mocked the claim that we live in 'the best of all possible worlds' in his satire Candide?

Voltaire gave the slogan to Candide's mentor, Professor Pangloss, who insists that all turns out for the best. Inspired partly by the 1755 Lisbon earthquake, the tale ends on humbler advice: 'we must cultivate our garden'.

Which Italian friar, who proposed that the stars are distant suns, was burned at the stake in Rome in 1600?

Giordano Bruno also suggested those suns had planets that might hold life. In 1889, after the Church lost control of Rome, the city raised a monument to him on the spot where he died.

The word 'philosophy' joins the Greek 'philos', meaning 'loving', with 'sophia', a word that means what?

Wisdom is the 'sophia' in philosophy, and the same Greek word survives as the name Sophia. A philosopher is literally a friend of wisdom, since 'philos' covers friend as well as loving.

In the best-known paradox of Zeno of Elea, which swift Greek hero can never catch a tortoise that has a head start?

Achilles would need an infinite number of steps, Zeno argued, because the gap between the two can be divided without end. Some mathematicians hold that modern calculus dissolves the puzzle.

In the paradox named after medieval philosopher Jean Buridan, which animal starves between two identical piles of hay?

A donkey is the victim, though the tale appears nowhere in Buridan's surviving writings. Later critics invented the dithering animal to satirise his view that we must always choose the greater good.

Aristotle's followers at the Lyceum were called Peripatetics, a name that comes from the Greek for which activity?

Walking gave the school its name, but probably by way of the Lyceum's covered walkways, the peripatoi. The story that Aristotle lectured while strolling is a legend that grew up later.

Which sculptor's bronze The Thinker began as a figure called The Poet, seated above his doorway The Gates of Hell?

Auguste Rodin based the doorway on Dante's Divine Comedy. Foundry workers gave the seated figure its lasting name because it reminded them of a Michelangelo statue nicknamed Il Pensieroso.

Which English statesman coined the word 'utopia', from the Greek for 'no place', as the name of an imaginary island?

Thomas More first called the island Nusquama, the Latin for 'no-place', before choosing the Greek. In English the word sounds just like 'eutopia', which would translate as 'good place'.

Which French mathematician argued that believing in God is the safest bet, a line of reasoning known as his 'wager'?

Blaise Pascal never published the argument: it surfaced in the Pensées, a collection of his unfinished notes printed after his death. It is counted as the first formal use of decision theory.

Which American writer's night in jail for refusing to pay a poll tax led to his essay 'Civil Disobedience'?

Henry David Thoreau withheld the tax in protest at slavery and the Mexican–American War. His case for breaking unjust laws later shaped the thinking of Leo Tolstoy and Mahatma Gandhi.

Which Roman philosopher and playwright tutored the young Nero, who as emperor later ordered him to take his own life?

Seneca had been recalled from exile on Corsica to take the job. He was accused of joining a plot to assassinate his former pupil, a charge of which he may well have been innocent.

Which maxim was the best known of the sayings inscribed on the Temple of Apollo at Delphi?

Know thyself first meant something closer to 'know your limits': remember you are mortal and keep your place. It probably began as a popular proverb, whatever the tradition that credits it to the Seven Sages.

Which Greek thinker's followers at Croton in Italy believed in reincarnation and were forbidden to eat fava beans?

Pythagoras is famous for a theorem he may never have proved, and no authentic writings of his survive. The teaching most securely tied to him is that the soul is immortal and enters a new body after death.

Which fallacy swaps an opponent's real argument for a weaker version that is easier to knock down?

Straw man tactics are also known in Britain as an Aunt Sally, after a pub game in which players throw sticks at a post to knock a skittle off the top.

Which philosopher, the mother of the author of Frankenstein, wrote A Vindication of the Rights of Woman?

Mary Wollstonecraft argued that women only appeared inferior to men because they were denied an education. She died at 38, eleven days after giving birth to the future novelist.

Which Glasgow professor of moral philosophy wrote The Theory of Moral Sentiments years before The Wealth of Nations?

Adam Smith used 'sympathy' as his word for the fellow-feeling behind our moral judgments. He had studied the subject at Glasgow from the age of 14, under Francis Hutcheson.

Which novel by Norway's Jostein Gaarder walks its teenage protagonist through the whole history of philosophy?

Sophie's World was reported to be the best-selling book in the world in 1995, four years after it first appeared in Norwegian. By 2011 it had been translated into 59 languages.

Which Victorian thinker's On Liberty argues that power may be used over a person only to prevent harm to others?

John Stuart Mill put only his own name on the essay, though he wrote it with his wife, Harriet Taylor Mill. She died suddenly in 1858, just as the final draft was nearly complete.

Which thinker coined 'the banality of evil' while covering Adolf Eichmann's trial in Jerusalem for The New Yorker?

Hannah Arendt had fled Germany as Hitler rose to power. Her claim was that Eichmann was no fanatic or sociopath but a mundane man chasing promotion, who leaned on clichés instead of thinking for himself.

Which French baron argued in The Spirit of the Laws that legislative, executive and judicial power should be kept apart?

Montesquieu published the book anonymously in 1748, and within three years the Catholic Church had put it on its list of prohibited books. Its three-branch scheme influenced the drafters of the US Constitution.

Which insect did the Taoist sage Zhuangzi dream he was, waking unsure whether it was now dreaming of being him?

A butterfly, flitting about and pleased with itself, was the dream. The puzzle of telling the dreamer from the dream grew so famous that whole plays were later written around it.

Which southern African philosophy, named with a Zulu word for 'humanity', is sometimes rendered 'I am because we are'?

Ubuntu served as a guiding ideal in South Africa's move from apartheid to majority rule, and the word even appears in the country's interim constitution of 1993.

Which English pioneer of scientific method is said to have caught a fatal chill while stuffing a hen with snow?

Francis Bacon wanted to see whether snow would preserve meat as salt does, in the tale told by the biographer John Aubrey. He died of pneumonia in 1626 at a friend's house in Highgate.

Which Dutch philosopher was expelled from Amsterdam's Jewish community at 23 and later made his living grinding lenses?

Baruch Spinoza later refused the chair of philosophy at Heidelberg, perhaps for fear it would curb his freedom of thought. His Ethics was published only after his death, by friends working in secrecy.

Which 'laughing philosopher' from Abdera is chiefly remembered for an ancient atomic theory of the universe?

Democritus earned the nickname through his stress on the value of cheerfulness. How much of atomism is truly his is unclear, since the earliest sources credit his teacher Leucippus with creating it.

Which Greek word for cleansing did Aristotle borrow in the Poetics to describe the effect of tragedy on its audience?

Catharsis was a term for cleansing the body before Aristotle applied it to the mind. He compared what tragedy and music do to a spectator with what a purge does physically.

Which form of argument, in which two premises lead to a conclusion, did Aristotle set out in his Prior Analytics?

Syllogism theory reached medieval Europe second-hand: until the mid-12th century logicians knew only part of Aristotle's work, and the return of the Prior Analytics helped launch what was called the New Logic.

Which American philosophical movement is credited to Charles Sanders Peirce, William James and John Dewey?

Pragmatism got its name from Peirce in the early 1870s, but the word first reached print only in 1898, in a piece by James that gave him the credit.

Which Austrian-born philosopher of science argued that a theory counts as scientific only if it could be proved false?

Karl Popper pointed to swans: no number of white ones can prove that all swans are white, yet a single black one is enough to refute the claim.

Which American physicist turned philosopher of science introduced the phrase 'paradigm shift' in a 1962 book?

Thomas Kuhn argued in The Structure of Scientific Revolutions that science does not advance smoothly: long calm spells of 'normal science' are interrupted by upheavals that replace the whole framework.

Which ethical outlook, taught in ancient Greece by Aristippus of Cyrene, holds that pleasure is the only good?

Hedonism became a family business: Aristippus named his daughter Arete his intellectual heiress, and she and her son, also called Aristippus, organised his ideas into the Cyrenaic school.

Which Sicilian philosopher originated the theory of four elements and, in legend, leapt into Mount Etna to seem a god?

Empedocles hoped people would think he had vanished and become immortal, the story goes, but the volcano threw back one of his bronze sandals and gave the trick away.

Which dialogue by Plato has a group of Athenian friends take turns giving speeches in praise of the god of love?

In the Symposium, the comic playwright Aristophanes claims humans were once double creatures until Zeus chopped them in half, which is why each of us goes looking for an other half.

Which Greek word, literally 'good spirit', names the highest human good in Aristotle, often translated as flourishing?

Eudaimonia is commonly translated as happiness, but Aristotle meant something bigger than feeling happy. He described it as 'doing and living well': a life of virtuous activity in accordance with reason.

Which philosopher, born a slave in Roman Phrygia, had his teachings written down by his pupil Arrian in the Enchiridion?

Epictetus began to teach once he was freed. When the emperor Domitian banished philosophers from Rome, he simply founded a new school at Nicopolis in north-western Greece.

Which American philosopher imagined an 'experience machine' that could feed anyone a lifetime of simulated pleasures?

Robert Nozick gave three reasons to stay unplugged, the first being that we want to do certain things and not just have the experience of doing them. The puzzle appears in his book Anarchy, State, and Utopia.

Which Oxford philosopher's 1949 book The Concept of Mind mocked mind-body dualism as 'the ghost in the machine'?

Gilbert Ryle held that treating the mind as a separate thing is a 'category mistake'. He once asked an Oxford audience what is wrong with saying a field holds three things: two cows and a pair of cows.

Which philosopher coined the terms 'hard problem' and 'easy problems' of consciousness in a 1994 talk in Tucson?

David Chalmers counted it 'easy', by comparison, to explain how a brain discriminates and integrates information. The hard part is why any of that processing is accompanied by experience at all.

Which school of philosophy was established by Edmund Husserl, a mathematician by training who later taught at Freiburg?

Phenomenology nearly lost its archive. After Husserl died in 1938, some 40,000 pages of his shorthand manuscripts were smuggled to Leuven in Belgium by a Franciscan priest.

Which Córdoba-born judge wrote so many studies of Aristotle that medieval Europe simply called him 'The Commentator'?

Averroes fell from favour late in life: a tribunal condemned his teachings, ordered his books burned and banished him to Lucena. Dante still gave him a place among the great non-Christian thinkers in his Divine Comedy.

Which Persian physician-philosopher imagined a 'floating man', cut off from every sensation, who still knows he exists?

Avicenna devised the thought experiment while imprisoned in a castle near Hamadan. His Canon of Medicine became a standard text in medieval European universities and stayed in use as late as 1650.

Which Córdoba-born rabbi, later a court physician in Saladin's Egypt, wrote The Guide for the Perplexed?

Maimonides was a boy when the Almohads took Córdoba and made its Jews choose between conversion to Islam and exile; his family eventually left Spain. In Hebrew he is the Rambam, short for 'our Rabbi, Moshe son of Maimon'.

Which third-century philosopher's writings were arranged by his pupil Porphyry into six groups of nine, the Enneads?

Plotinus so distrusted the material world that, Porphyry reports, he refused to have his portrait painted. The tidy six-by-nine plan was the editor's doing: he split and joined texts to reach 54 treatises.