SIDNEY MORGENBESSER was a dominant figure in American philosophy of the past 50 years. For nearly half a century he taught in the philosophy faculty of Columbia University, and was appointed the John Dewey Professor of Philosophy. Noam Chomsky, the theoretician of language and one of America’s leading intellectuals, described Morgenbesser as “one of the most knowledgeable and in many ways profound thinkers of the modern period”.

His life embodied many of the paradoxes which he relished so much as a thinker. He influenced two generations of American philosophers without writing a major book or formulating a new doctrine. When challenged why he had written so little, he fired back: “Moses published one book. What did he do after that?”

His written legacy consists of some 50 articles, many co-authored, and six anthologies. He was a key figure in an Ivy League university, although he was trained far outside that magic circle. He got his first degree at the City College of New York, his doctorate at the University of Pennsylvania, and before going to Columbia, taught at Swarthmore College and the New School of Social Research. The one institution of worldwide renown which he did attend was the Jewish Theological Seminary in New York, the principal seminary for training conservative rabbis.

He was ordained, lost his faith, and never tried too hard to find it again. He swapped belief for doubt rather than the certainty of atheism. A few weeks before he died, he asked his Columbia colleague David Albert, with tongue in cheek and doubt in his mind: “Why is God making me suffer so much? Just because I do not believe in him?” — and that encounter reveals the keys to his abiding influence: wit and charm.

These packaged a mind as sharp as a scalpel that sought to cut through to the heart of every question. With that he bequeathed to his students an attitude of inquiry that is the basis of all philosophy. And he brought to philosophy one legacy from his training in cutting through the Talmud, the source book of rabbinic Judaism. The basis of its reasoning is that every word has implications that demand dissection rather than dismissal. That experience drew Morgenbesser to the school of linguistic philosophy as taught in Oxford by A. J. Ayer and J. L. Austin, although no one school could quite contain the range of his mind.

He embraced logic as expounded by Karl Popper at the London School of Economics, and constantly took his students on expeditions to widen the frontiers of meaning. He was, in addition, the scourge of the slipshod. And that, added to the sheer force of his personality, turned his students into disciples. As one of them, the younger philosopher Robert Nozick, wrote: “I majored in Sidney Morgenbesser.”

It was an experience as daunting as it was formative. As Arthur Danto, one of his faculty colleagues at Columbia recalls, in a seminar Morgenbesser would ask students and colleagues: “Let me see if I understand you.”

He would then go on to restate their thesis in his own formulation. “And that would be that. It was one of the ordeals you had to survive.”

There are numerous (possibly apocryphal) examples of Morgenbesser’s mordant wit. He, it is said, described Gentile ethics as entailing “ought implies can” while in Jewish ethics “can implies don’t”. Pragmatism, he said, works in theory but not in practice.

Once, when he was about to light a cigarette on the New York subway, a cop said to him: “If I let you do it, I’d have to let everyone do it.” “Who do you think you are — Kant?” replied Morgenbesser. The cop took this for a vulgarity and hustled him down to the police station.

A famous Morgenbesser anecdote arose during a lecture by J. L. Austin in Oxford. Austin said it was peculiar that although there are many languages in which a double negative makes a positive, no example existed where two positives expressed a negative. In a dismissive voice, Morgenbesser replied from the audience, “Yeah, yeah . . .”

His childhood in a poor Lower East side home — his father was a tailor working in a sweat shop — left Morgenbesser also with a lifelong commitment to left-wing politics. He joined his students in an anti-police demonstration during the l968 student unrest at Columbia. The police broke it up with a baton charge, and Morgenbesser got hit over the head. The experience led to one of his most quoted but least revealing bons mots.

He was asked whether the police had treated him unjustly or unfairly. “Unfairly yes, unjustly no,” he said. “It was unfair to be hit over the head but not unjust since they hit everyone else over the head, too.”

Applying his own rigorous standards of analysis to that statement, some of his students argued that it may have been unjust, in that no guilt had been proved against him, but it was by no means unfair as all his fellow demonstrators got the same treatment. To dismember obiter dicta, even his own, was the ultimate legacy Morgenbesser left to the teaching of philosophy in America.

He is survived by his long-term partner Joann Haimson.

Sidney Morgenbesser, philosopher, was born on September 22, 1921. He died on August 1, 2004, aged 82.