Sir Michael Anthony Eardley Dummett (; 27 June 1925 – 27 December 2011) was an English academic described as "among the most significant British philosophers of the last century and a leading campaigner for racial tolerance and equality." He was, until 1992, Wykeham Professor of Logic at the University of Oxford. He wrote on the history of analytic philosophy, notably as an interpreter of Frege, and made original contributions particularly in the philosophies of mathematics, logic, language and metaphysics.
He was known for his work on truth and meaning and their implications to debates between realism and anti-realism, a term he helped to popularise. In mathematical logic, he developed an intermediate logic, a logical system intermediate between classical logic and intuitionistic logic that had already been studied by Kurt Gödel: the Gödel–Dummett logic. In voting theory, he devised the Quota Borda system of proportional voting, based on the Borda count, and conjectured the Gibbard–Satterthwaite theorem together with Robin Farquharson; he also devised the condition of proportionality for solid coalitions. Besides his main work in analytic philosophy, he also wrote extensively on the history of card games, particularly on tarot card games.
He was married to the political activist Ann Dummett from 1951 until his death in 2011.
Born 27 June 1925 at his parents' house, 56, York Terrace, Marylebone, London, Dummett was the son of George Herbert Dummett (1880 – 12 November 1969), later of Shepherd's Cottage, Curridge, Berkshire, a silk merchant and rayon dealer, and Mabel Iris (1893–1980), daughter of the civil servant and conservationist Sir Sainthill Eardley-Wilmot (himself grandson of the politician Sir John Eardley-Wilmot, 1st Baronet). He studied at Sandroyd School in Surrey, at Winchester College as a scholar, and at Christ Church, Oxford, which awarded him a major scholarship in 1943. He was called up for military service that year and served until 1947, first as a private in the Royal Artillery, then in the Intelligence Corps in India and Malaya. In 1950 he graduated with a first in Politics, Philosophy and Economics from Oxford and was elected a Prize Fellow of All Souls College, Oxford.
Dummett was a research fellow at All Souls College, Oxford until 1979, and also Reader in Philosophy of Mathematics at Oxford University from 1962 to 1974. In 1979, he became Wykeham Professor of Logic at Oxford, a post he held until retiring in 1992. During his term as Wykeham Professor, he held a Fellowship at New College, Oxford. He has also held teaching posts at Birmingham University, UC Berkeley, Stanford University, Princeton University, and Harvard University. He won the Rolf Schock prize in 1995, and was knighted in 1999. He was the 2010 winner of the Lauener Prize for an Outstanding Œuvre in Analytical Philosophy.
During his career at Oxford, Dummett supervised many philosophers who went on to distinguished careers, including Peter Carruthers, Adrian Moore, Ian Rumfitt, and Crispin Wright.
Dummett's work on the German philosopher Frege has been acclaimed. His first book Frege: Philosophy of Language (1973), written over many years, is seen as a classic. It was instrumental in the rediscovery of Frege's work, and influenced a generation of British philosophers.
In his 1963 paper "Realism", he popularised a controversial approach to understanding the historical dispute between realist and other non-realist philosophy such as idealism, nominalism, irrealism. He classed all the latter as anti-realist and argued that the fundamental disagreement between realist and anti-realist was over the nature of truth.
For Dummett, realism is best understood as semantic realism, i.e. the view that every declarative sentence in one's language is bivalent (determinately true or false) and evidence-transcendent (independent of our means of coming to know which), while anti-realism rejects this view in favour of a concept of knowable (or assertible) truth. Historically, these debates had been understood as disagreements about whether a certain type of entity objectively exists or not. Thus we may speak of realism or anti-realism with respect to other minds, the past, the future, universals, mathematical entities (such as natural numbers), moral categories, the material world, or even thought. The novelty of Dummett's approach consisted in seeing these disputes as at base analogous to the dispute between intuitionism and Platonism in the philosophy of mathematics.
Dummett espoused semantic anti-realism, a position suggesting that truth cannot serve as the central notion in the theory of meaning and must be replaced by verifiability. Semantic anti-realism is sometimes related to semantic inferentialism.
Dummett was politically active, through his work as a campaigner against racism. He let his philosophical career stall in order to influence civil rights for minorities during what he saw as a crucial period of reform in the late 1960s. He also worked on the theory of voting, which led to his introduction of the Quota Borda system.
Dummett drew heavily on his work in this area in writing his book On Immigration and Refugees, an account of what justice demands of states in relationship to movement between states. Dummett, in that book, argues that the vast majority of opposition to immigration has been founded on racism, and says that this has especially been so in the UK. In the book, Dummett argued in favour of open borders and mass migration, except when states were "under special threat" and could therefore refuse entry.
In 1954, in Germany, Dummett studied what had survived of Frege's Nachlass. He later recounted how he had been deeply shocked to discover from diary fragments that the man he had "revered" as "an absolutely rational man" was, at the end of his life, a "virulent" anti-Semite of "extreme right-wing opinions".
In 1955–1956, while in Berkeley, California, Dummett and his wife joined the NAACP. In June 1956 he met Martin Luther King Jr. while visiting San Francisco, and heard from him of Alistair Cooke providing the British public with what King defined as "biased and hostile reports" of the Civil Rights Movement and specifically of the Montgomery bus boycott. Dummett travelled to Montgomery and wrote his own account. However, The Guardian refused to publish Dummett's article and his refutation of Cooke's version of the Montgomery events, even in a shortened account as a Letter to the Editor; the BBC also refused to publish it.
Dummett and Robin Farquharson published influential articles on the theory of voting, in particular conjecturing that deterministic voting rules with more than three issues faced endemic strategic voting. The Dummett–Farquharson conjecture was proved by Allan Gibbard, a philosopher and former student of Kenneth J. Arrow and John Rawls, and by the economist Mark A. Satterthwaite.
After the establishment of the Farquharson–Dummett conjecture by Gibbard and Satterthwaite, Dummett contributed three proofs of the Gibbard–Satterthwaite theorem in a monograph on voting. He also wrote a shorter overview of the theory of voting, for the educated public.
Dummett was a scholar in the field of card-game history, with numerous books and articles to his credit. He was a founding member of the International Playing-Card Society, in whose journal The Playing-Card he regularly published opinions, research and reviews of current literature on the subject; he was also a founder of the Accademia del Tarocchino Bolognese in Bologna. His historical work on the use of the tarot pack in card games, The Game of Tarot: From Ferrara to Salt Lake City, attempted to establish that the invention of Tarot could be set in 15th-century Italy. He laid the foundation for most subsequent research on the game of tarot, including exhaustive accounts of the rules of all hitherto known forms of the game. Sylvia Mann goes as far as to say that The Game of Tarot "is the most important book on cards ever written."