People

167 of them, roughly in order of birth. Some posed the problem, some solved it, and a few are here because they got it wrong in an instructive way.

515 BCE–450 BCEParmenides of EleaAuthor of a hexameter poem, substantial parts of which survive, arguing that what-is must be ungenerated, indivisible and unchanging, and that motion and plurality belong to the deceptive "way of opinion". Zeno's paradoxes were written in defence of this position.2
490 BCE–420 BCEProtagoras of AbderaThe first and most celebrated of the sophists, and by ancient report the first man to charge a fee for teaching. He is remembered for "man is the measure of all things", for professing agnosticism about the gods, and for training students to argue either side of any case — a skill that, in the Paradox of the Court, is turned against him by his own pupil.1
490 BCE–430 BCEZeno of EleaPupil and associate of Parmenides in the Greek colony of Elea. He wrote a single book of arguments designed to show that the pluralist common-sense picture of the world is more absurd than his teacher's claim that reality is one and changeless. None of the book survives intact; the motion paradoxes are known only through Aristotle's paraphrases and later commentary.2
470 BCE–399 BCESocratesAthenian philosopher who wrote nothing but whose method of inquiry — question and answer, pushing interlocutors to examine their assumptions — defined the philosophical tradition. He is the principal speaker in Plato's dialogues, including the Meno, where he draws out the paradox of inquiry: we cannot search for what we already know, and we cannot search for what we do not know, since we would not recognise it if we found it. He was tried and executed by Athens in 399 BCE on charges of impiety and corrupting the youth.1
428 BCE–348 BCEPlatoAthenian philosopher, student of Socrates and teacher of Aristotle. His dialogues — among the best-preserved texts of ancient philosophy — invented or recorded the tradition of systematic philosophical argument in the West. The Meno, one of his middle dialogues, poses the paradox of inquiry: how can one search for something without already knowing what one is looking for? Plato's answer, the doctrine of recollection, holds that learning is a matter of remembering knowledge the soul possessed before birth. His founding of the Academy made Athens the centre of philosophical education for centuries.1
384 BCE–322 BCEAristotleStudent of Plato and founder of the Lyceum. His Physics is the earliest surviving text to state Zeno's four arguments against motion, and his replies — that a length and the time to cross it are divisible in exactly the same way, and that an infinity of divisions is potential rather than actual — set the terms of the debate for the next two thousand years.3
279 BCE–206 BCEChrysippus of SoliThird head of the Stoa and the principal architect of Stoic logic. Diogenes Laertius' catalogue of his lost works lists at least six titles on the Liar, which makes him the first thinker known to have treated the paradox as a serious research programme rather than a debating trick.1
46–119PlutarchGreek historian, biographer and priest at Delphi. His Parallel Lives pairs Greek and Roman figures. Chapter 23 of the Life of Theseus records the ship preserved by the Athenians and notes that philosophers already used it as a standing example in disputes about growth and identity — making Plutarch a reporter of the puzzle rather than its inventor.1
125Aulus GelliusRoman author of the Attic Nights, a twenty-book commonplace collection of notes on law, grammar, philosophy and anecdote compiled in the second century CE. His chapter on "convertible" arguments contains the earliest surviving telling of the lawsuit between Protagoras and Euathlus.1
480–560Simplicius of CiliciaNeoplatonist commentator on Aristotle, writing in the sixth century CE. His enormous commentary on the Physics quotes older texts at length, and is the sole surviving witness to the verbatim words of several Presocratics. Almost everything anyone can quote of Zeno exists because Simplicius copied it out roughly a thousand years after it was written.2
1058–1111Abū Ḥāmid al-GhazālīPersian theologian, jurist and philosopher. In The Incoherence of the Philosophers (c. 1095) he argued against the Avicennan claim that a will can never choose between indistinguishable alternatives, using the case of a man who must take one of two identical dates. The example predates Buridan by two and a half centuries and reaches the opposite conclusion.1
1300–1361John BuridanJean Buridan was a secular master of arts at the University of Paris, twice its rector, and the most influential logician of his century. He held that the will can defer choice when the intellect finds no decisive reason either way. The starving donkey attached to his name appears nowhere in his surviving writings; it is a caricature aimed at that doctrine by later critics. His birth and death dates are both approximate.1
1564–1642Galileo GalileiPisan mathematician, astronomer and physicist. Beyond the telescope and the law of falling bodies, his final book — the Discorsi of 1638, written under house arrest — contains the first clear statement that the squares can be matched one-for-one with the whole numbers, and the first honest account of why that ought to worry you.1
1571–1630Johannes KeplerImperial mathematician at Prague and author of the three laws of planetary motion. In his Dissertatio cum Nuncio Sidereo of 1610 — a rapid open response to Galileo's telescopic discoveries — he argued that the darkness of the night sky is itself evidence that the realm of stars is bounded. It is the earliest clear statement of the problem later named after Olbers.1
1588–1679Thomas HobbesEnglish philosopher, best known for Leviathan. In De Corpore (1655) he sharpened the Ship of Theseus into its modern form by imagining a second ship rebuilt from the discarded planks, and observed that treating both as the original would give you two bodies numerically the same, which he called absurd.1
1608–1647Evangelista TorricelliStudent and successor of Galileo, and inventor of the barometer. In 1641 he discovered that the solid of revolution obtained by rotating the curve y = 1/x around the x-axis from x = 1 to infinity has finite volume but infinite surface area — a result so counterintuitive that it generated immediate controversy. The shape is now called Gabriel's Horn or Torricelli's Trumpet. His work on indivisibles and infinitely extended solids contributed to the foundations of integral calculus.1
1632–1677Baruch SpinozaDutch philosopher and lens-grinder. In the scholium to Ethics II.49 he takes up the man suspended in perfect equilibrium and simply concedes the point: such a person would indeed die of hunger and thirst, and should be reckoned an ass rather than a man. He uses the case to attack the idea of a free-floating faculty of will.1
1632–1704John LockeEnglish philosopher and physician. The chapter "Of Identity and Diversity", added to the second edition of his Essay Concerning Human Understanding in 1694, separated the identity of a person from the identity of a man and of a substance, and grounded personal identity in continuity of consciousness. Every later psychological-continuity theory is a descendant of that chapter.1
1656–1742Edmond HalleyAstronomer Royal, financier of Newton's Principia, and predictor of the return of the comet that bears his name. In two papers read to the Royal Society in 1721 he took up the question of why an infinite sphere of fixed stars does not set the night sky ablaze, and offered an argument from the diminishing apparent size of remote stars that does not, in fact, work.1
1687–1759Nicolaus BernoulliNicolaus I Bernoulli, professor at Basel and a nephew of Jacob and Johann Bernoulli. He worked mainly through correspondence, and it is a letter that earns him his place here: writing to Pierre Rémond de Montmort on 9 September 1713, he proposed the coin-doubling wager whose expected value is infinite. He never published a resolution of it himself.1
1700–1782Daniel BernoulliBest known for the principle relating fluid speed to pressure that carries his name. His 1738 St Petersburg paper did something else entirely: it proposed that people value money not by its amount but by a concave function of it, and that "the utility resulting from any small increase in wealth will be inversely proportionate to the quantity of goods previously possessed" — the first statement of diminishing marginal utility, and the seed of modern expected-utility theory.1
1704–1752Gabriel CramerGeneva mathematician remembered for Cramer's rule for solving linear systems. In a 1728 letter to Nicolaus Bernoulli he proposed two responses to the St Petersburg wager that are still the standard ones: value money by its square root rather than its amount, or cap value above some threshold entirely. Both ideas predate Daniel Bernoulli's published paper.1
1713–1768Laurence SterneIrish-born English novelist whose eccentric masterpiece, The Life and Opinions of Tristram Shandy, Gentleman (published in volumes from 1759 to 1767), introduced the narrator who cannot finish his own autobiography because writing about his life takes longer than living it. The novel's preoccupation with time, memory, and the impossibility of complete self-narration gave Bertrand Russell the vehicle for a paradox about infinite sets: if Tristram had infinite time, could he eventually finish? The novel is now recognised as a forerunner of modernist fiction.1
1718–1751Jean-Philippe Loys de ChéseauxAstronomer of Lausanne, best remembered for his observations of the great comet of 1743. In an appendix to that work he gave the first genuinely quantitative treatment of the dark-sky problem, computing how far one must look before stars tile the whole sky, and proposed — as Olbers would independently, eighty years later — that a tenuous absorbing medium swallows the missing light.1
1733–1799Jean-Charles de BordaFrench mathematician, physicist and naval officer. In 1770 he read a memoir to the Académie royale des sciences proposing the rank-scoring election method now called the Borda count, published in 1781 as Mémoire sur les élections au scrutin. He also worked on fluid mechanics, surveying instruments, and the meridian measurements that fixed the length of the metre.1
1743–1794Nicolas de CondorcetMarie Jean Antoine Nicolas de Caritat, Marquis de Condorcet: mathematician, permanent secretary of the Académie royale des sciences, and the last of the philosophes. His 1785 Essai applied probability theory to voting and juries, producing both the jury theorem and the cycle that bears his name. He was an early opponent of slavery and an advocate of women's suffrage, sat in the Legislative Assembly, and voted against executing the king. Proscribed during the Terror, he wrote his Esquisse d'un tableau historique des progrès de l'esprit humain while in hiding, and was found dead in a cell at Bourg-la-Reine in March 1794.2
1758–1840Heinrich Wilhelm OlbersBremen physician who observed the sky from the top floor of his house after his patients were seen. He discovered the asteroids Pallas (1802) and Vesta (1807) and devised a still-used method for computing cometary orbits. His 1823 essay "Ueber die Durchsichtigkeit des Weltraums" restated the puzzle of the dark night sky and proposed that interstellar matter absorbs the missing light — an answer now known to be wrong, attached to a question that has carried his name ever since.1
1809–1849Edgar Allan PoePoet, critic and inventor of the detective story. In his last major work, Eureka: A Prose Poem (1848), he set out a speculative cosmology and, in a single celebrated passage, gave the correct shape of the answer to the dark night sky: the void between the stars exists because light from the most distant of them has not yet had time to reach us. He offered it as intuition rather than physics, and it was ignored for a century.1
1822–1900Joseph BertrandProfessor at the École Polytechnique and the Collège de France, and permanent secretary of the Académie des Sciences. He is remembered for Bertrand's postulate on prime numbers, for the Bertrand model of price competition in economics, and for two quite different paradoxes in his 1889 "Calcul des probabilités" — the box paradox, and the random-chord paradox that showed "at random" is not a well-defined instruction.1
1831–1879James Clerk MaxwellAuthor of the equations that unified electricity, magnetism and light, and a founder of the statistical theory of gases. In an 1867 letter to Peter Guthrie Tait he imagined "a very observant and neat-fingered being" who could sort fast molecules from slow ones and so, he said, "pick a hole" in the second law of thermodynamics. He published the thought experiment in Theory of Heat (1871). The word "demon" was William Thomson's, not his, and Maxwell disliked it.1
1831–1916Richard DedekindBraunschweig mathematician, the last doctoral student of Gauss, and one of the architects of modern foundations. In Was sind und was sollen die Zahlen? (1888) he turned Galileo's embarrassment into a definition: a set is infinite precisely when it can be matched one-for-one with a proper part of itself.2
1835–1882William Stanley JevonsEnglish economist and logician, one of the three independent discoverers of marginal utility alongside Carl Menger and Léon Walras. The Coal Question (1865) made his reputation and contains the efficiency argument now named after him; The Theory of Political Economy (1871) set out the marginalist case. He also built one of the earliest logic machines and did pioneering work on index numbers. He drowned while swimming near Hastings at the age of 46.1
1837–1910Robert GiffenScottish statistician and economist. He worked as a journalist at The Economist under Walter Bagehot, then headed the statistical department of the Board of Trade, and served as president of the Royal Statistical Society from 1882 to 1884. He was knighted in 1895. He wrote extensively on working-class budgets and on the price of bread, but no passage stating the phenomenon Marshall named after him has ever been located in his published work.1
1842–1924Alfred MarshallProfessor of political economy at Cambridge and the dominant figure in English-language economics for a generation. His Principles of Economics (1890) introduced supply-and-demand diagrams, price elasticity, consumer surplus and the short-run/long-run distinction, and remained the standard textbook for decades. The third edition of 1895 added the passage attributing upward-sloping demand for bread to Robert Giffen.1
1845–1918Georg CantorBorn in Saint Petersburg, professor at Halle for his entire career, and the creator of set theory. He proved that infinite sets come in different sizes, invented the transfinite cardinals and ordinals, and defended the completed infinite against fierce opposition — most bitterly from his former teacher Leopold Kronecker. He suffered recurrent depression from 1884 and died in a sanatorium in Halle.2
1848–1925Gottlob FregeInventor of modern quantificational logic and the founder of logicism, the programme of deriving arithmetic from logic alone. His Grundgesetze der Arithmetik rested on Basic Law V, which Russell's 1902 letter showed to be inconsistent. Frege appended a candid acknowledgement to the second volume and eventually abandoned the logicist project.1
1862–1943David HilbertThe dominant mathematician of his generation and the centre of gravity of Göttingen until the Nazi purges emptied it. His 1900 list of twenty-three problems set much of the century's agenda, and his defence of Cantor's transfinite mathematics — "no one shall expel us from the paradise that Cantor has created" — supplied both the formalist programme and the hotel that carries his name.3
1867–1928G. G. BerryGeorge Godfrey Berry, a junior librarian at the Bodleian Library in Oxford. He corresponded with Bertrand Russell and sent him the puzzle about the least integer not nameable in a small number of syllables. Russell published it in 1906 with explicit credit to Berry, and it has carried his name ever since. He published almost nothing under his own name.1
1868–1942Felix HausdorffFounder of modern point-set topology and of measure and dimension theory. His 1914 paradoxical decomposition of the sphere minus a countable set is the direct ancestor of the Banach–Tarski theorem. Persecuted as a Jew under the Nazi regime and facing internment, he took his own life with his wife and her sister in Bonn in January 1942.1
1871–1953Ernst ZermeloGerman mathematician who discovered the paradox of the set of all sets not members of themselves independently of Russell, around 1899-1902, and discussed it with Hilbert's circle in Göttingen without publishing it. His 1908 axiomatisation of set theory replaced unrestricted comprehension with the axiom schema of separation, the move that still keeps mathematics consistent today.1
1871–1951George Udny YuleOne of the founders of modern statistics, a student of Karl Pearson and later a lecturer at Cambridge. His 1903 paper on the association of attributes described the reversal effect now called Simpson's paradox two generations before Simpson, which is why some writers call it the Yule–Simpson effect.1
1872–1970Bertrand RussellBritish philosopher, logician and public intellectual. In 1901 he found the contradiction that bears his name while examining Cantor's diagonal argument, and in 1902 reported it to Frege in a letter that demolished the foundations of Frege's life's work. His theory of types (1908) and Principia Mathematica (1910-13, with A. N. Whitehead) were attempts to rebuild mathematics on paradox-free ground.6
1872–1946Paul LangevinProfessor at the Collège de France, known for the Langevin equation, the theory of paramagnetism and the invention of ultrasonic echo-ranging. At the 1911 philosophy congress in Bologna he described a traveller who leaves Earth at high speed and returns to find that far more time has passed at home than aboard the ship — the thought experiment now called the twin paradox, though Langevin never mentioned twins.1
1879–1955Albert EinsteinAuthor of special relativity (1905), general relativity (1915) and the light quantum hypothesis for which he received the 1921 Nobel Prize. He was one of the founders of quantum theory and its most formidable lifelong critic, arguing through the 1927 and 1930 Solvay conferences and the 1935 EPR paper that the quantum description of reality is incomplete rather than wrong. Bell's theorem later showed that the kind of completion Einstein wanted is not available.4
1881–1953Lewis Fry RichardsonMathematician and meteorologist who pioneered numerical weather prediction and the mathematical study of the causes of war. While studying the relationship between shared border length and likelihood of conflict, he noticed that the reported length of borders between countries varied wildly depending on the source — because different maps used different scales. His posthumous paper on this observation, published in 1961, laid the groundwork for what Benoit Mandelbrot later formalised as the coastline paradox and fractal geometry.1
1882–1927Leonard NelsonGerman neo-Kantian philosopher who revived the Friesian school and applied rigorous logical methods to ethical and epistemological questions. In 1908, with Kurt Grelling, he published the paradox about self-describing words that bears both their names. Nelson's broader philosophical project was to ground ethics in reason without dogmatic metaphysics; he founded the Philosophisch- Politische Akademie, a school that combined rigorous philosophy with progressive political commitment.1
1882–1957Maurice KraitchikNumber theorist who worked on factorisation methods that later fed into the quadratic sieve, and an editor of the journal Sphinx. He is remembered here for his recreational writing: the necktie paradox and the wallet game in his "Mathematical Recreations" are the earliest widely circulated forms of what is now the two envelopes problem. He posed the puzzle without resolving it.1
1883–1946John Maynard KeynesThe most influential economist of the twentieth century. His General Theory of Employment, Interest and Money (1936) overturned classical macroeconomics by arguing that aggregate demand drives output and employment, and that private virtues — including saving — can produce public vices when pursued collectively. The paradox of thrift, the clearest example of this fallacy of composition, became a central teaching device of Keynesian economics. He also made foundational contributions to probability theory and was a key architect of the Bretton Woods international monetary system.1
1883–1953Richard von MisesApplied mathematician who worked on aerodynamics, plasticity and numerical analysis, and who built one of the twentieth century's two great foundations for probability — the frequentist theory of the "Kollektiv", the rival to Kolmogorov's axiomatic approach. Dismissed from Berlin in 1933, he taught in Istanbul and then at Harvard. His 1939 Istanbul paper on occupancy probabilities contains the first published treatment of the birthday problem.1
1885–1977John Edensor LittlewoodCambridge analyst, and for thirty-five years G. H. Hardy's collaborator on the distribution of primes, Waring's problem and Fourier analysis. His 1953 collection "A Mathematician's Miscellany" preserves, in a few lines, a card version of the exchange paradox that he credits to Erwin Schrödinger — one of the earliest records of the two envelopes argument.2
1885–1962Niels BohrDanish physicist, Nobel laureate of 1922, and the central figure of what became known as the Copenhagen interpretation. His institute in Copenhagen trained much of the founding generation of quantum theory. His doctrine of complementarity — that a quantum system's description depends irreducibly on the experimental arrangement used to probe it — was his standing reply to Einstein, including his same-titled 1935 rebuttal of the EPR argument.2
1886–1942Kurt GrellingGerman philosopher and logician, student of David Hilbert and Leonard Nelson. In 1908 he and Nelson jointly published the paradox that bears their names: the Grelling-Nelson paradox, which shows that the ordinary notion of a word describing itself generates the same kind of contradiction that Russell found in naive set theory. Grelling was Jewish and was murdered at Auschwitz in 1942.1
1887–1961Erwin SchrödingerViennese physicist who formulated wave mechanics in 1926, giving quantum theory the equation that bears his name, and shared the 1933 Nobel Prize in Physics with Paul Dirac. He was never reconciled to the Copenhagen reading of his own equation, and his 1935 cat scenario was written as a criticism of it, not an endorsement. He left Austria after the Anschluss, spent the war years at the Dublin Institute for Advanced Studies, and there wrote "What Is Life?" (1944), which influenced a generation of molecular biologists.2
1892–1945Stefan BanachThe founder of modern functional analysis and the central figure of the Lwów school, which did much of its work in the Scottish Café over a notebook of open problems. Banach spaces, the Hahn–Banach theorem and the Banach fixed point theorem all carry his name. He survived the German occupation feeding lice at Weigl's typhus institute and died of lung cancer in 1945.1
1896–1966Boris PodolskyBorn in Taganrog, emigrated to the United States in 1913, and worked with Einstein at the Institute for Advanced Study in Princeton. He wrote the actual text of the 1935 EPR paper. Einstein later complained privately that the argument had been "smothered by the formalism" in Podolsky's drafting, and restated it in his own simpler terms in subsequent years.1
1898–1964Leó SzilárdPhysicist who conceived the nuclear chain reaction in 1933, drafted the letter Einstein sent to Roosevelt in 1939, and later campaigned against the weapons he had helped make possible. His 1929 paper on Maxwell's demon reduced the problem to a single-molecule engine and argued that the demon's act of acquiring information must itself generate entropy — the first quantitative link between information and thermodynamics.1
1899–1982Joseph BerksonPhysician and statistician, head of the division of biometry and medical statistics at the Mayo Clinic for three decades. He coined the term "logit", argued at length against the causal interpretation of the early smoking–cancer studies, and in 1946 described the selection artefact in hospital data that now bears his name.1
1901–1983Alfred TarskiLogician and mathematician, born in Warsaw, from 1942 at Berkeley. He gave the modern semantic definition of truth and proved the undefinability of truth within a formal system. His first major result, with Banach in 1924, was the paradoxical decomposition of the ball — work he began as a doctoral student of Leśniewski.4
1901–1954Enrico FermiArchitect of the first self-sustaining nuclear reactor and of the theory of beta decay, and famous for order-of-magnitude estimation from almost no data. Over lunch at Los Alamos in the summer of 1950 he interrupted a conversation about flying saucers to ask "Where is everybody?" — a question about the feasibility of interstellar travel that was later built into an argument he never published.1
1902–1985Karl MengerMember of the Vienna Circle and a founder of dimension theory, later professor at Illinois Institute of Technology. His 1934 paper on uncertainty in value theory delivered the sharpest blow to the St Petersburg literature: for any unbounded utility function whatsoever, a "super-St-Petersburg" game can be built whose expected utility is again infinite. Bounded utility is therefore not a convenience but a requirement.1
1902–1994Karl PopperPhilosopher of science, author of The Logic of Scientific Discovery (1934) and The Open Society and Its Enemies (1945), the latter written in exile in New Zealand during the Second World War. He is best known for falsifiability as the criterion of scientific status, and, in a single footnote of The Open Society, for the formulation now called the paradox of tolerance.1
1903–1957John von NeumannContributor to set theory, quantum mechanics, game theory, computer architecture and much else. In 1929 he isolated the property of a group that actually drives paradoxical decomposition — what is now called amenability — and thereby explained why the Banach–Tarski phenomenon appears in three dimensions but not in one or two.1
1904–1968George GamowPhysicist and cosmologist — quantum tunnelling in alpha decay, Big Bang nucleosynthesis, early work on the genetic code — and one of the great popularisers of science. His One Two Three... Infinity (1947) carried Hilbert's hotel, and much of Cantor's transfinite arithmetic, to a general readership for the first time.1
1905–1995Albert W. TuckerPrinceton mathematician, known for the Karush-Kuhn-Tucker conditions in optimisation and as the doctoral adviser of John Nash. In 1950, needing a way to explain the Flood-Dresher game to an audience of psychologists, he invented the story of two prisoners interrogated separately and gave the dilemma the name it has carried ever since.1
1906–1978Kurt GödelLogician of the first rank. He proved the completeness of first-order logic (1929), then in 1931 the two incompleteness theorems that ended Hilbert's programme in its original form. He later proved the consistency of the continuum hypothesis and the axiom of choice with ZF (1938-40). A Platonist about mathematical truth, he resisted the subjectivist readings his theorems are still routinely given.1
1907–1989J. Barkley RosserAmerican logician, a student of Alonzo Church. In 1936 he strengthened Gödel's first incompleteness theorem by replacing the hypothesis of omega-consistency with plain consistency, using a cleverly modified self-referential sentence now called the Rosser sentence. The Kleene-Rosser paradox and the Church-Rosser theorem also bear his name.1
1908–1991Duncan BlackScottish economist, usually credited as the founder of public choice theory. His 1948 paper "On the Rationale of Group Decision-making" introduced single-peaked preferences and the median voter result, showing exactly when majority rule is safe from Condorcet cycles. His 1958 book The Theory of Committees and Elections went back to the archives and recovered the work of Condorcet, Borda and Charles Dodgson for modern economics.1
1908–1991Merrill M. FloodMathematician at the RAND Corporation and later the University of Michigan. In January 1950, with Melvin Dresher, he ran the experiment that first exhibited the game now called the Prisoner's Dilemma, and he published the results with the players' round-by-round commentary in 1958.1
1908–2000Willard Van Orman QuinePhilosopher and logician at Harvard for most of his career. He supplied the vocabulary this site uses for classifying paradoxes — veridical, falsidical, antinomy — in "The Ways of Paradox" (1962). His two-page note "On a So-called Paradox" (1953) located the flaw in the condemned prisoner's reasoning at its very first step.1
1909–1995Nathan RosenEinstein's assistant at Princeton in the mid-1930s and the third author of the 1935 EPR paper. With Einstein he also produced the Einstein–Rosen bridge (1935), the first wormhole solution in general relativity. He later helped found the physics department at the Technion in Haifa.1
1911–2010Maurice AllaisFrench economist, engineer and physicist, awarded the 1988 Nobel Memorial Prize for his work on market equilibrium and the efficient use of resources. Much of his most original work — on capital theory, on monetary dynamics, and on choice under risk — was published only in French and reached the Anglophone mainstream decades late. In 1952 he put the questionnaire now known as the Allais paradox to a room of leading decision theorists, and spent the following decades arguing that expected utility theory was not a defensible account of rational choice.1
1911–1992Melvin DresherMathematician at the RAND Corporation, where he worked on the application of game theory to military strategy. With Merrill Flood he devised the two-player game whose structure Albert Tucker later dressed in the story of two prisoners.1
1911–1985René BarjavelFrench novelist, journalist and screenwriter. His 1943 novel "Le Voyageur Imprudent" ("The Imprudent Traveller") contains the scene generally credited with fixing the grandfather paradox in its now-standard form: a time traveller who kills his own ancestor. He later wrote "La Nuit des Temps" (1968) and worked on the screenplays of the "Don Camillo" films.1
1912–1954Alan TuringBritish mathematician who in 1936 defined the abstract machine model that bears his name, proved that no machine can decide whether an arbitrary machine halts, and used that result to settle Hilbert's Entscheidungsproblem in the negative. His argument recast Gödel's incompleteness as a fact about computation, and founded computer science in the process.2
1913–1996Paul ErdősOne of the most prolific mathematicians in history, with around 1,500 papers and a famously itinerant life. He appears here for a humbling reason: he reportedly refused to accept the Monty Hall answer until shown a simulation.1
1914–2010Martin GardnerAuthor of the Mathematical Games column in Scientific American from 1956 to 1981, and of more than seventy books. His 1963 column and the 1969 collection named after it, The Unexpected Hanging and Other Mathematical Diversions, carried the prediction paradox from a narrow philosophy journal debate to a general readership.2
1915–2003Garrett HardinProfessor of human ecology at the University of California, Santa Barbara. His 1968 Science essay "The Tragedy of the Commons" became one of the most cited papers ever published in the journal. Hardin's stated purpose was to argue for coercive limits on population growth, and his later writing - including "Lifeboat Ethics" (1974) and work with anti-immigration organisations he helped found - is widely described by scholars as nativist and racist.1
1916–1996Donald T. CampbellAmerican social scientist who did foundational work on research design, validity and evaluation. His writing on planned social change gave the corruption of social indicators its sharpest independent statement, now known as Campbell's Law.1
1919–2007Edward Robert HarrisonCosmologist at the University of Massachusetts Amherst, co-author of the Harrison–Zel'dovich spectrum of primordial density fluctuations. His Darkness at Night (1987) traced the dark-sky problem from Kepler to modern cosmology, recovered Poe's priority, and made the case — now standard — that the finite age of the universe, not expansion or absorption, is the reason the night is dark.1
1921–2002John RawlsHarvard philosopher whose A Theory of Justice (1971) reshaped Anglophone political philosophy. Section 35 of that book addresses the toleration of the intolerant directly, and concludes that a just society should restrict the liberty of intolerant sects only when the tolerant sincerely and with reason believe their own security is genuinely in danger.1
1921–2017Kenneth ArrowAmerican economist whose Columbia doctoral dissertation, published in 1951 as Social Choice and Individual Values, proved that no method of aggregating ranked preferences can satisfy four elementary conditions at once. He went on to co-author the Arrow–Debreu proof of the existence of general equilibrium and to found modern health economics and the economics of information. He shared the 1972 Nobel Memorial Prize with John Hicks and, at 51, remains the youngest economics laureate.1
1922–1990Cyrus LevinthalAmerican molecular biologist at MIT and later Columbia, and a pioneer of interactive computer graphics for molecules. In 1968–69 he pointed out that a protein searching its conformations at random could not fold in the age of the universe, yet real proteins fold in microseconds.1
1922–2019Edward H. SimpsonBritish statistician and civil servant. He worked at Bletchley Park during the Second World War and spent most of his career in the Home Civil Service. His single, brief 1951 paper on contingency tables gave its name to the reversal effect, although he was careful to credit the underlying observation to earlier writers and never claimed to have discovered it.1
1924–2010Benoit MandelbrotMathematician who created the field of fractal geometry. His 1967 paper "How Long Is the Coast of Britain?" — a direct response to Lewis Fry Richardson's observations — introduced the idea that coastlines and similar irregular curves have no well-defined length and can be characterised by a non-integer fractal dimension. He went on to show that fractals appear throughout nature: in snowflakes, lightning bolts, mountain ranges, and financial markets. The Mandelbrot set, the most famous object in fractal geometry, bears his name.1
1924–2023Robert SolowMIT economist and 1987 Nobel laureate whose growth model made technological progress the central driver of long-run output. A single aside in a 1987 book review — that the computer age was visible everywhere except in the productivity statistics — named the productivity paradox.1
1926Richard EasterlinAmerican economist at the University of Southern California, generally regarded as the founder of the economics of happiness. His 1974 chapter "Does Economic Growth Improve the Human Lot?" set out the tension between the cross-sectional and time-series relationships between income and reported wellbeing, and he has defended and refined the claim for fifty years. He is also known for the Easterlin hypothesis linking cohort size to fertility and relative economic fortune.1
1927–2015Charles A. Thomas Jr.American molecular biologist who worked on the physical organisation of chromosomal DNA. His 1971 review in the Annual Review of Genetics named the C-value paradox: the amount of DNA in a genome bears no reliable relation to the apparent complexity of the organism carrying it.1
1927–2016Marvin MinskyCo-founder of the MIT Artificial Intelligence Laboratory and one of the founding figures of the field. In The Society of Mind he argued that the mental work we find easiest is the work built from the largest and oldest machinery, which is exactly why it is hardest to introspect on and hardest to reproduce.1
1927–1999Rolf LandauerIBM physicist whose 1961 paper established that logically irreversible operations — above all, erasing a bit — carry an unavoidable thermodynamic cost of at least kT ln 2 of heat per bit. His slogan, "information is physical", became the organising principle of the physics of computation.1
1927–1999William NewcombPhysicist at the Lawrence Livermore National Laboratory whose single most lasting contribution to intellectual history was never published. Around 1960 he posed, in private conversation, the decision problem that bears his name. The problem reached a wider audience only when Robert Nozick described it in 1969, crediting Newcomb by name. Newcomb's own views on the correct choice are not on record.1
1928–2015John F. Nash Jr.Proved in 1950 that every finite game with mixed strategies has at least one equilibrium point, the concept now called the Nash equilibrium. It is the solution concept that makes the Prisoner's Dilemma precise: mutual defection is an equilibrium even though both players would prefer mutual cooperation. Shared the 1994 Nobel Memorial Prize in Economic Sciences.1
1928–1990John Stewart BellBelfast-born physicist who spent most of his career at CERN doing accelerator and particle theory, and pursued quantum foundations as what he called his "hobby". His 1964 paper turned Einstein's philosophical complaint into an inequality that experiments could test, and his 1966 review dismantled von Neumann's supposed proof that hidden variables were impossible. He died of a stroke in 1990, the year he had been nominated for a Nobel Prize.1
1930–1982Hugh Everett IIIPrinceton graduate student whose 1957 dissertation proposed that the wave function never collapses and that measurement simply entangles observer with system — the "relative state" formulation later popularised by Bryce DeWitt as the many-worlds interpretation. Discouraged by the reception, including a cool meeting with Bohr in Copenhagen, he left academia for defence operations research and never returned.1
1931–2023Daniel EllsbergEconomist and strategic analyst who trained at Harvard under Thomas Schelling and worked at the RAND Corporation. His 1961 doctoral dissertation introduced what became known as the Ellsberg Paradox, showing that people systematically prefer bets on known probabilities over bets on unknown ones — violating the axioms of subjective expected utility theory. He is equally known for leaking the Pentagon Papers to the press in 1971, for which he faced federal espionage charges that were eventually dismissed.1
1932Denis OsborneBritish physicist who, during a visit to a school in Tanzania in 1966, was asked by student Erasto Mpemba whether his observation that hot water can freeze faster than cold water was real. Osborne tested it back in Dar es Salaam and confirmed it. He co-authored the 1969 paper in Physics Education that introduced the effect to the wider scientific community, crediting Mpemba in the title. The experiment described in that paper remains the canonical documentation of what became known as the Mpemba effect.1
1932Michael H. HartAstrophysicist whose 1975 paper in the Quarterly Journal of the Royal Astronomical Society gave the first rigorous form of the modern argument: starting from plausible colonisation speeds, the Galaxy should have been settled long ago, so the absence of extraterrestrials on Earth is itself evidence about their existence. He also did early work on the habitable zones of planetary systems.1
1933Amartya SenIndian economist and philosopher, awarded the 1998 Nobel Memorial Prize for work on welfare economics, social choice and famine. Collective Choice and Social Welfare (1970) mapped the escape routes from Arrow's theorem, showing that admitting interpersonal comparisons of welfare restores possibility. He also proved the impossibility of a Paretian liberal, and his capability approach reshaped how development is measured.1
1933–2012Elinor OstromPolitical economist at Indiana University and the first woman to receive the Nobel Memorial Prize in Economic Sciences, awarded in 2009 for her analysis of economic governance and especially the commons. Her fieldwork on irrigation systems, fisheries, forests and alpine pastures showed that communities routinely build durable rules for shared resources without either privatisation or state control, and she distilled the recurring features of the successful cases into eight design principles.1
1934–2024Daniel KahnemanPsychologist whose collaboration with Amos Tversky produced the heuristics-and-biases programme and, in 1979, prospect theory — the model that turned the Allais paradox from an anomaly into the foundation of behavioural economics. He was awarded the 2002 Nobel Memorial Prize in Economic Sciences, which Tversky did not live to share. His later work covered experienced versus remembered wellbeing, and he ended his career championing adversarial collaboration as a way to settle scientific disputes.2
1935Igor NovikovRussian astrophysicist known for work on black holes and cosmology, and for the self-consistency principle that bears his name: if closed timelike curves exist, the only physical processes on them are those whose local solutions are globally consistent, so that paradoxical histories simply have probability zero. He collaborated with Kip Thorne's Caltech group on the physics of time machines in the late 1980s and 1990s.1
1935–2015Jerry B. HarveyProfessor of management science at George Washington University. His 1974 article "The Abilene Paradox: The Management of Agreement" opened with a true story about his own family driving fifty-three miles to Abilene, Texas, on a July afternoon that none of them wanted, and used it to argue that organisations fail at least as often from mismanaged agreement as from mismanaged conflict.1
1936Charles GoodhartBritish economist, for many years an adviser at the Bank of England and later professor at the London School of Economics. In a 1975 conference paper on UK monetary management he observed that any statistical regularity tends to collapse once it is used as an instrument of control — the remark that became Goodhart's Law.1
1936Judea PearlComputer scientist at UCLA and winner of the 2011 Turing Award for his work on probabilistic and causal reasoning in artificial intelligence. He developed Bayesian networks and then the do-calculus, which turns causal questions into formal ones. His treatment of Simpson's paradox — that no amount of data can tell you which table to trust, only a causal model can — is the standard modern resolution.2
1937–1996Amos TverskyIsraeli cognitive psychologist, latterly at Stanford, and Daniel Kahneman's collaborator on judgement under uncertainty and prospect theory. He also worked on the foundations of measurement, on similarity, and on the axiomatics of choice. He died of metastatic melanoma in 1996, six years before the Nobel Prize recognised the work.1
1938Dietrich BraessMathematician at the Ruhr University Bochum, best known for numerical analysis and the finite element method. In a 1968 paper on traffic planning he showed that adding a new road to a congested network can increase everyone's travel time once drivers re-optimise - the effect now universally called Braess's paradox.1
1938–2002Robert NozickHarvard philosopher best known for Anarchy, State, and Utopia (1974), a libertarian counterpoint to Rawls. In 1969 he published the paper that introduced Newcomb's Problem to academic philosophy, framing the tension between two apparently compelling decision principles and declining to adjudicate between them. He subsequently championed evidential decision theory, though he acknowledged the opposing argument's force throughout his career.1
1940Kip ThorneCaltech relativist, shared the 2017 Nobel Prize in Physics for the LIGO detection of gravitational waves, and a co-founder of LIGO itself. With Michael Morris and Ulvi Yurtsever he showed in 1988 how a traversable wormhole could in principle be turned into a time machine, which reopened serious physics work on causality violation — including his group's collaboration with Novikov on self-consistency.1
1940Leonard SusskindStanford theorist, one of the originators of string theory, and Hawking's chief antagonist in the black hole information debate — a dispute he narrated in "The Black Hole War" (2008). With Gerard 't Hooft he developed the holographic principle, and with Larus Thorlacius and John Uglum the principle of black hole complementarity.1
1940–2022Saul KripkeLogician and philosopher, best known for the possible-worlds semantics of modal logic and for Naming and Necessity. His 1975 paper "Outline of a Theory of Truth" replaced Tarski's hierarchy of languages with a single language whose truth predicate is partial, built up to a fixed point — the most influential technical response to the Liar in the twentieth century.1
1941–2001David LewisOne of the most influential analytic philosophers of the twentieth century, at Princeton from 1970. He is best known for modal realism, the counterfactual analysis of causation, and the Principal Principle linking chance to rational credence. His reply to Elga, published shortly before his death, is the canonical statement of the halfer position on Sleeping Beauty.1
1941Leslie LamportAmerican computer scientist whose work defined how the field reasons about distributed systems: logical clocks and the happened-before relation (1978), the Byzantine Generals Problem (1982) with Robert Shostak and Marshall Pease, sequential consistency, and the Paxos consensus algorithm (1998). He also wrote LaTeX. He received the 2013 ACM Turing Award for imposing "clear, well-defined coherence on the seemingly chaotic behaviour of distributed computing systems".2
1941Marilyn StrathernBritish social anthropologist, Professor of Social Anthropology at Cambridge and a leading analyst of audit culture. Her 1997 essay on ratings in British universities supplied the phrasing by which Goodhart's Law is now almost always quoted: "When a measure becomes a target, it ceases to be a good measure."1
1941Steve SelvinProfessor of biostatistics at the University of California, Berkeley. In 1975 he wrote the short letter to The American Statistician that first posed, and then named, the Monty Hall problem.1
1942–2017Derek ParfitPhilosopher at All Souls College, Oxford. Reasons and Persons (1984) argued through fission and teletransportation cases that questions of personal identity can be empty, and that what matters in survival is psychological continuity and connectedness rather than identity itself.1
1942John ClauserCo-author of the 1969 CHSH inequality, which recast Bell's theorem into a form that a real laboratory could test, and with Stuart Freedman performed the first such experiment in 1972 at Berkeley. He expected to confirm hidden variables and was disappointed by his own result. He shared the 2022 Nobel Prize in Physics with Alain Aspect and Anton Zeilinger.1
1942–2018Stephen HawkingCambridge theorist who, with Roger Penrose, proved the singularity theorems of general relativity, and who then showed in 1974–75 that black holes radiate and therefore have a temperature. He spent the following three decades arguing — first for, then against — the conclusion that this radiation destroys information. Diagnosed with motor neurone disease at 21, he worked for more than fifty years afterwards and wrote "A Brief History of Time" (1988).2
1943Charles H. BennettIBM researcher, co-inventor of quantum key distribution (1984, with Gilles Brassard) and quantum teleportation (1993). In 1973 he showed that computation can in principle be made logically reversible, and in 1982 he used that result to close the Maxwell's-demon problem: the demon's measurement need cost nothing, but clearing its memory to measure again must pay Landauer's bill.1
1943Richard PetoBritish statistician and epidemiologist at Oxford, best known for large-scale work on the health effects of smoking and on cancer trial methodology. In a 1975 paper on cancer and ageing in mice and men he noted that cancer incidence does not scale with body size across species — the observation later named Peto's paradox.1
1943Robert AxelrodPolitical scientist at the University of Michigan. In 1980 he invited researchers to submit computer programs to play the iterated Prisoner's Dilemma against one another, ran two round-robin tournaments, and found that the simplest entry submitted - Anatol Rapoport's four-line TIT FOR TAT - won both. His 1984 book The Evolution of Cooperation turned the result into a research programme spanning biology, economics and international relations.1
1943Sheldon RossProbabilist and author of widely used textbooks in probability and stochastic processes. His name is attached to the Ross-Littlewood paradox, a supertask thought experiment about a vase and numbered balls, which he popularised as a vehicle for exploring the mathematics of infinite sets and the limits of classical notions of convergence. His textbooks, including A First Course in Probability, have introduced the subject to generations of students.1
1944–2007Jim GrayAmerican computer scientist who did more than anyone to make database transactions a rigorous, engineerable idea: the ACID properties, two-phase locking, two-phase commit, and recovery. His 1978 lecture notes on database operating systems named the two generals paradox and set out the problem of agreement over unreliable communication for a generation of practitioners. He received the 1998 Turing Award. He was lost at sea in January 2007.1
1945Anton ZeilingerAustrian experimentalist who pioneered multi-particle entanglement, quantum teleportation, and entanglement-based quantum cryptography, and pushed Bell tests to ever longer distances and tighter loopholes. His group also demonstrated matter-wave interference with large molecules such as C60. He shared the 2022 Nobel Prize in Physics with Alain Aspect and John Clauser.1
1946Barry SchwartzPsychologist, for many years at Swarthmore College. His 2004 book The Paradox of Choice argued that the expansion of consumer choice past a certain point raises regret, anticipated regret and opportunity cost, and lowers satisfaction. The argument reached an enormous popular audience; the experimental evidence for its central claim has since proved much weaker than the book suggested.1
1946Gerard 't HooftUtrecht theorist who shared the 1999 Nobel Prize in Physics with Martinus Veltman for showing that non-abelian gauge theories are renormalisable. In 1993 he proposed dimensional reduction in quantum gravity — the idea that the degrees of freedom in a region are encoded on its boundary — which Susskind developed into the holographic principle.1
1946Kit FineSilver Professor of Philosophy at New York University. His 1975 paper "Vagueness, Truth and Logic" gave supervaluationism its definitive form, showing how a vague language can be evaluated across all its admissible sharpenings while preserving the logical truths of classical logic. He has since moved away from that view himself.1
1946Marilyn vos SavantColumnist for Parade magazine. Her 1990 answer to the Monty Hall problem was correct and provoked roughly ten thousand letters of disagreement, around a thousand from readers holding doctorates — one of the best-documented episodes of collective expert error on a simple question.1
1947Alain AspectFrench physicist whose experiments at Orsay between 1981 and 1982 gave the first high-precision violations of Bell's inequalities, including the celebrated 1982 run with time-varying analysers that closed the locality loophole to a substantial degree. He shared the 2022 Nobel Prize in Physics with John Clauser and Anton Zeilinger.1
1947Gregory ChaitinArgentine-American mathematician and computer scientist, one of the independent founders of algorithmic information theory alongside Kolmogorov and Solomonoff. His 1974 incompleteness theorem turns Berry's paradox into a precise limit: no consistent formal system can prove that any specific string has complexity much greater than the system's own description.1
1947Ken A. DillAmerican biophysical chemist at Stony Brook University, known for lattice models of folding and for the hydrophobic account of what drives a chain to collapse. His 1997 review with Hue Sun Chan, "From Levinthal to pathways to funnels", set out the funnel picture for a general audience.1
1947Scott L. FeldSociologist, latterly at Purdue University, who works on social network structure and the "focus theory" of how ties form. His 1991 paper "Why Your Friends Have More Friends Than You Do" named and explained the friendship paradox, using Coleman's data on adolescent friendships to show the effect in a real network.1
1948Don PageHawking's former graduate student, later at the University of Alberta. His 1993 analysis of the entanglement entropy of radiation from an evaporating black hole produced the Page curve, the quantitative signature that unitary evaporation must show and semiclassical Hawking radiation does not. Reproducing that curve became the concrete target that the 2019 island results finally hit.1
1948Graham PriestLogician at the CUNY Graduate Center, and the leading defender of dialetheism — the view that some contradictions are true. On his account the Liar sentence is both true and false, and the correct response is to give up the principle that a contradiction entails everything, rather than to restrict truth or self-reference.1
1948Hans MoravecAustrian-born roboticist, long at the Carnegie Mellon Robotics Institute, known for early autonomous vehicle navigation and for forecasts of machine capability. His 1988 book Mind Children states the observation that carries his name: reasoning is computationally cheap, perception and mobility are extraordinarily expensive.1
1948Nancy LynchAmerican computer scientist and professor at MIT, the leading figure in the theory of distributed computing. She co-authored the 1985 FLP impossibility result, the 2002 proof of Brewer's CAP conjecture with Seth Gilbert, and the input/output automata framework used to specify and verify concurrent systems. Her textbook "Distributed Algorithms" (1996) is the standard reference.2
1950Erasto MpembaTanzanian schoolboy who, in 1963, noticed that hot ice-cream mixture froze faster than cold mixture when placed in the same freezer. His physics teacher dismissed the observation, but when physicist Denis Osborne visited the school in 1966, Mpemba asked him about it directly. Osborne confirmed the effect experimentally and co-authored the 1969 paper introducing it to the scientific literature — with Mpemba's name first on the byline, an unusual acknowledgment for a student. The effect now bears his name.1
1953David DeutschOxford physicist, a founder of quantum computation, and an outspoken advocate of the Everett interpretation. His 1985 paper defined the universal quantum Turing machine; his 1991 paper gave a consistency condition for quantum systems on closed timelike curves that removes the grandfather paradox at the cost of a branching, self-consistent density matrix.1
1953Peter G. WolynesAmerican theoretical chemist, now at Rice University, who brought the statistical mechanics of spin glasses to protein folding. With Joseph Bryngelson he introduced the principle of minimal frustration in 1987, the idea that grew into energy landscape theory and the folding funnel.1
1954–2018Joseph PolchinskiSanta Barbara string theorist who discovered D-branes (1995), a result that made the microscopic counting of black hole entropy possible. With Ahmed Almheiri, Donald Marolf and James Sully he formulated the 2012 firewall argument, showing that black hole complementarity, the equivalence principle and unitarity cannot all be true at once.1
1954Rodney BrooksAustralian roboticist, former director of the MIT Computer Science and Artificial Intelligence Laboratory and co-founder of iRobot and Rethink Robotics. His behaviour-based robotics argued that intelligence rests on perception and action rather than on symbolic reasoning laid over them.1
1954Steven PinkerCanadian-American cognitive scientist at MIT and later Harvard. In The Language Instinct (1994) he gave Moravec's observation its most quoted formulation: the hard problems of artificial intelligence turned out to be easy, and the easy ones — recognising a face, crossing a room — turned out to be hard.1
1955Timothy WilliamsonWykeham Professor of Logic at the University of Oxford from 2000 to 2024. His 1994 book Vagueness is the canonical statement of epistemicism: the view that vague terms do have sharp boundaries and that vagueness is a form of ignorance, not of meaning. The position keeps classical logic intact at the cost of a claim most people find hard to swallow.1
1958Barry NalebuffProfessor at the Yale School of Management, co-author of "Thinking Strategically" and "Co-opetition", and later co-founder of the drinks company Honest Tea. From 1987 to 1990 he wrote the Puzzles column in the Journal of Economic Perspectives; his 1989 instalment recast an old exchange paradox in terms of two envelopes and gave the problem the form it now has.1
1958José OnuchicBrazilian-American physicist at Rice University who, with Wolynes, Nymeyer and Socci, developed the energy landscape theory of folding and coined the language of the folding funnel that is now standard in the field.1
1959Robin HansonEconomist at George Mason University, known for prediction markets, futarchy, and The Age of Em. His 1998 essay "The Great Filter" reframed the Fermi question as a search for the improbable step between dead matter and a visible interstellar civilisation, and pointed out the uncomfortable corollary: the more easily life arises, the more likely the filter lies ahead of us.1
1962Erik BrynjolfssonAmerican economist, long at MIT and later director of the Digital Economy Lab at Stanford. His firm-level work with Lorin Hitt showed that the returns to computing were real but arrived only alongside organisational change, and his later "productivity J-curve" applies the same argument to artificial intelligence.1
1962Nicholas A. ChristakisPhysician and social scientist at Yale, director of the Human Nature Lab. With James Fowler he studied how behaviours and states — obesity, smoking, happiness — propagate through social networks, and turned the friendship paradox into a practical instrument for detecting outbreaks before they show up in population surveillance.1
1968Juan MaldacenaArgentine physicist at the Institute for Advanced Study whose 1997 conjecture relating string theory in anti-de Sitter space to a conformal field theory on its boundary (AdS/CFT) is the most-cited result in modern theoretical physics. It supplies the sharpest existing argument that black hole evaporation is unitary, because the boundary theory is manifestly so.1
1969Sheena IyengarProfessor at Columbia Business School. With Mark Lepper she ran the 2000 field study in a California grocery store in which a display of 24 jams drew more passers-by but produced far fewer purchases than a display of 6 - the single most cited piece of evidence for choice overload, and one that later replication attempts and meta-analyses have not reliably reproduced.1
1970James H. FowlerPolitical scientist at the University of California, San Diego, working on social networks, behaviour spread and the genetics of political participation. With Nicholas Christakis he co-authored the 2010 study that used friends of randomly chosen students as early sensors for an influenza outbreak.1
1974Adam ElgaPhilosopher at Princeton working on formal epistemology, self-locating belief and disagreement. His three-page 2000 paper in Analysis gave the Sleeping Beauty problem its name and its thirder answer, and started a debate that has run for more than two decades without resolution.1
1976T. Ryan GregoryCanadian evolutionary biologist at the University of Guelph and curator of the Animal Genome Size Database. His 2001 review argued that the C-value puzzle should be renamed the C-value enigma, because the question is no longer why genome size varies at all but what causes and maintains the variation.1
—Daniel AbadiAmerican computer scientist and database researcher, professor at the University of Maryland and previously at Yale. He worked on column-store systems and on the architecture of distributed databases, and in 2012 proposed PACELC, an extension of CAP that adds the trade-off systems actually face most of the time: when there is no partition, consistency must be paid for in latency.1
—Diogenes LaertiusCompiler of the Lives and Opinions of Eminent Philosophers, ten books of biography, gossip, book lists and quotation. He is an uneven historian and a priceless one: for many ancient thinkers, including Eubulides and much of the Stoa, his catalogue is the only reason we know what they wrote about.2
—Epimenides of KnossosA Cretan poet and purifier of the seventh or sixth century BCE, surrounded by legend — including a fifty-seven-year sleep in a cave. A line attributed to him, "Cretans are always liars", is quoted in the Epistle to Titus and is the reason his name is attached to the Liar paradox. He almost certainly never intended it as a paradox, and it is not one.1
—Eric BrewerAmerican computer scientist, professor at UC Berkeley and later a vice president at Google. He built some of the first large clustered web services at Inktomi, and in a 2000 keynote to the ACM Symposium on Principles of Distributed Computing proposed the conjecture that consistency, availability and partition tolerance cannot all be had at once. Twelve years later he wrote a widely read correction of how his own conjecture had come to be misused.1
—Eubulides of MiletusMegarian logician, a contemporary and critic of Aristotle. Diogenes Laertius credits him with a famous group of puzzles including the Liar, the Sorites (the heap), the Hooded Man and the Horned Man. He is the earliest person to whom the Liar paradox is attributed by any surviving source.2
—Marshall PeaseResearcher at SRI International and lead author of the 1980 paper "Reaching Agreement in the Presence of Faults", which first proved that agreement among processes exchanging unauthenticated messages requires more than three times as many participants as there are faulty ones. He co-authored the 1982 Byzantine Generals paper that gave the result its enduring name.1
—Matthew KillingsworthSenior fellow at the Wharton School of the University of Pennsylvania and creator of the Track Your Happiness experience-sampling project, which collects in-the-moment wellbeing reports by smartphone. His 2021 analysis of 1.7 million such reports found that experienced wellbeing keeps rising with income above $75,000 a year, contradicting the earlier plateau finding, and he then settled the disagreement through an adversarial collaboration with Daniel Kahneman.1
—Michael J. FischerAmerican computer scientist, long a professor at Yale, whose work spans computational complexity, cryptography and distributed computing. With Nancy Lynch and Michael Paterson he proved in 1985 that no deterministic protocol can solve consensus in an asynchronous system if even one process may crash — a result that reshaped how distributed systems are specified and built.1
—Michael S. PatersonBritish computer scientist and long-serving professor at the University of Warwick, where he founded the Centre for Discrete Mathematics and its Applications. He worked on algorithms, complexity and combinatorics, and with Michael Fischer and Nancy Lynch proved the 1985 impossibility of asynchronous deterministic consensus.1
—Ole PetersPhysicist at the London Mathematical Laboratory and the Santa Fe Institute, and the leading advocate of "ergodicity economics". His 2011 paper argues that the St Petersburg paradox — and much of decision theory besides — arises from quietly substituting an average over parallel possible worlds for an average over time in a single world, two quantities that coincide only for ergodic processes. Wealth dynamics are not ergodic.1
—Peter UngerPhilosopher at New York University. In a run of papers around 1979 he pressed the sorites in the direction almost everyone else refuses to go, concluding that ordinary terms such as "stone" and "table" are incoherent and that there are no ordinary things — and, in a companion paper, no people either.1
—Robert ShostakAmerican computer scientist who worked at SRI International on SIFT, a fault-tolerant flight-control computer built for NASA, where the Byzantine agreement problem arose as a concrete engineering requirement rather than a puzzle. He co-authored both the 1980 agreement paper and the 1982 Byzantine Generals paper, and contributed to early automated theorem proving. He later founded companies including Vocera Communications.1
—Roy SorensenPhilosopher at the University of Texas at Austin, and the author of the Stanford Encyclopedia entries on vagueness and on epistemic paradoxes. His book Blindspots (1988) introduced the idea of a proposition that is true but cannot consistently be believed by a particular person — which is exactly what the judge's sentence is for the condemned prisoner. He also defends epistemicism about vagueness.2
—Seth GilbertComputer scientist working on distributed algorithms and fault tolerance, a professor at the National University of Singapore. As a doctoral student with Nancy Lynch at MIT he co-authored the 2002 paper that turned Brewer's CAP conjecture into a proved theorem by making its terms precise — and in doing so made clear how much narrower the theorem is than the slogan built on it.1
—Theodore SiderProfessor of philosophy at Rutgers University. His Four-Dimensionalism (2001) is the standard defence of the view that objects persist by having temporal parts, which turns the Ship of Theseus from a question about one object into a question about two overlapping spacetime worms.1
—Timothy Y. ChowMathematician, with a 1995 MIT doctorate under Richard Stanley, who has worked in combinatorics and at the Center for Communications Research. His 1998 American Mathematical Monthly survey of the surprise examination paradox is the standard map of the literature, sorting five decades of proposed solutions into a small number of genuinely distinct positions.1