[...] If the Frankfurt School was the last hurrah of German romanticism, then Benjamin was its emblem, revealing the group in all its contradictions – Marxists without party, socialists dependent on capitalist money, beneficiaries of a society they sniffily disdained and without which they would have had nothing to write about.

For Marcuse fascism was not a break with the past, but a continuation of tendencies within liberalism that supported the capitalist economic system. This was the Frankfurt School orthodoxy – fascism wasn’t an abolition of capitalism, rather a means of ensuring its continued existence. Horkheimer once wrote ‘he who does not wish to speak of capitalism, should also be silent about fascism’. [...]

[...] Adorno fled first to Oxford where he would spend four years from 1934 to 1938 as an advanced student at Merton College – a demotion from his position as lecturer at Frankfurt. There were worse slights to his self-esteem: at Merton, he was obliged to dine communally. This was ‘like having to return to school’, he wrote, adding, with pardonable exaggeration, ‘in short, an extension of the Third Reich’. [...]

[...] ‘Once a formula was successful, the industry plugged the same thing over and over again. The result was to make music into a kind of social cement operating through distraction, displaced wish-fulfillment, and the intensification of passivity.’ In this, you might well think, Adorno was prescient: he recognised early the developments that would dominate television, film, commercial theatre, book publishing and the internet in the twentieth and twenty-first centuries, how the endless repetition of successful formulas, such as in sequels or online retailer recommendations based on past consumption patterns, keeps us in a kind of Sisyphean hell, buying and consuming minimally different cultural products.

That was one of the problems with the Germany to which he and Horkheimer returned: there were no Nazis any more. The returning exiles found their homeland in a state of mass denial. When Horkheimer visited Frankfurt in 1948 to discuss with the university authorities the possibility of re-establishing the Institute for Social Research, he found his former colleagues ‘as sweet as pie, smooth as eels and hypocritical … I attended a faculty meeting yesterday and found it too friendly by half and enough to make you want to throw up. All these people sit there as they did before the Third Reich … just as if nothing had happened … they are acting out a Ghost Sonata that leaves Strindberg standing.'

After the war, Habermas enrolled at the University of Bonn, later also studying philosophy at Göttingen and Zurich. Between 1949 and 1953, he spent four years studying Heidegger, so his letter to the philosopher was freighted with symbolic resonances. A young intellectual was calling out his older mentor, demanding that he not hide in silence but rather explain how he could have eulogised a politically criminal system. A new German generation was calling on an older one to account for itself, and perhaps atone for its sins

Frankfurt School critical theory was not supposed to be like this. Critical theory had something built into it akin to the Jewish taboo on calling God by his name: to do so would be premature since we are not yet in the messianic age. Similarly for critical theory, setting out a utopian vision would be premature; its self-imposed task was to negate the truth of the existing order rather than producing blueprints for a better one. And yet in An Essay on Liberation, Marcuse dared to imagine a new type of man who rejected the values of established societies. This new man was not aggressive, was incapable of fighting wars or creating suffering, and worked happily both collectively and individually for a better world rather than to further his own interests.

[...] When Jean-Paul Sartre and Marcuse arranged to meet at the Coupole in Paris in the late 1960s, Sartre worried how he could get through lunch without revealing the truth. ‘I have never read a word Marcuse has written’, he told his future biographer John Gerassi. ‘I know he has tried to link Marx and Freud. And I know he supports activist students. But I can’t possibly read his books by next week. Besides I don’t want to stop my research on Flaubert. So you join us. And if Marcuse gets too philosophical, if he uses the word reification just once, interrupt and say something provocative and political.’

In the event, over cassoulet, Sartre came up with an ingenious strategy for concealing his ignorance. He asked questions that suggested a greater familiarity with Marcuse’s works than he actually had. ‘Each time he answered, I picked out an apparent flaw in his answer to ask another question. But since the flaw was only apparent, he could answer my question to his great satisfaction. Thus his vanity soared happily.’ Indeed it did: as Gerassi put Marcuse into a taxi, the latter ‘shook both of my hands with genuine gratitude and said: “I had no idea he knew my work so well.”’

Grown-ups buy line-caught salmon, they don’t read Dialectic of Enlightenment. History has stopped and we live, don’t we, in the best of all possible worlds? In that best of all possible worlds, at the end of history, wrote Fredric Jameson in Late Marxism (1990), ‘the question about poetry after Auschwitz has been replaced with that of whether you could bear to read Adorno and Horkheimer next to the pool’. [...]