Ernest André Gellner FRAI (9 December 1925 – 5 November 1995) was a British-Czech philosopher and social anthropologist described by The Daily Telegraph, when he died, as one of the world's most vigorous intellectuals, and by The Independent as a "one-man crusader for critical rationalism".

[1] His first book, Words and Things (1959), prompted a leader in The Times and a month-long correspondence on its letters page over his attack on linguistic philosophy.

As the Professor of Philosophy, Logic and Scientific Method at the London School of Economics for 22 years, the William Wyse Professor of Social Anthropology at the University of Cambridge for eight years, and head of the new Centre for the Study of Nationalism in Prague, Gellner fought all his life—in his writing, teaching and political activism—against what he saw as closed systems of thought, particularly communism, psychoanalysis, relativism and the dictatorship of the free market.

[2] Gellner was born in Paris[3] to Anna, née Fantl, and Rudolf, a lawyer, an urban intellectual German-speaking Austrian Jewish couple from Bohemia (which, since 1918, was part of the newly established Czechoslovakia).

He interrupted his studies after one year to serve with the 1st Czechoslovak Armoured Brigade, which took part in the Siege of Dunkirk (1944–45), and then returned to Prague to attend university there for half a term.

One of his recollections of the city in 1945 was a communist poster saying: "Everyone with a clean shield into the Party", ostensibly meaning that those whose records were good during the occupation were welcome.

The same year, he began his academic career at the University of Edinburgh as an assistant to Professor John Macmurray in the Department of Moral Philosophy.

[5]Gellner's critique of linguistic philosophy in Words and Things (1959) focused on J. L. Austin and the later work of Ludwig Wittgenstein, criticising them for failing to question their own methods.

He obtained his Ph.D. in 1961 with a thesis on Organisation and the Role of a Berber Zawiya and became Professor of Philosophy, Logic and Scientific Method just one year later.

Described by the Oxford Dictionary of National Biography as "brilliant, forceful, irreverent, mischievous, sometimes perverse, with a biting wit and love of irony", he was famously popular with his students, was willing to spend many extra hours a day tutoring them, and was regarded as a superb public speaker and gifted teacher.

[3] His Plough, Sword and Book (1988) investigated the philosophy of history, and Conditions of Liberty (1994) sought to explain the collapse of socialism with an analogy he called "modular man".

It was obvious to me the moment I came across it, although initially, if your entire environment, and all the bright people in it, hold something to be true, you assume you must be wrong, not understanding it properly, and they must be right.

[5]Words and Things is fiercely critical of the work of Ludwig Wittgenstein, J. L. Austin, Gilbert Ryle, Antony Flew, P. F. Strawson and many others.

Ryle refused to have the book reviewed in the philosophical journal Mind (which he edited), and Bertrand Russell (who had written an approving foreword) protested in a letter to The Times.

Chris Hann, director of the Max Planck Institute for Social Anthropology, writes that following the hard-nosed empiricism of Bronisław Malinowski, Gellner made major contributions to the subject over the next 40 years, ranging from "conceptual critiques in the analysis of kinship to frameworks for understanding political order outside the state in tribal Morocco (Saints of the Atlas, 1969); from sympathetic exposition of the works of Soviet Marxist anthropologists to elegant syntheses of the Durkheimian and Weberian traditions in western social theory; and from grand elaboration of 'the structure of human history' to path-breaking analyses of ethnicity and nationalism (Thought and Change, 1964; Nations and Nationalism, 1983)".