From Postwar: A History of Europe Since 1945, by Tony Judt (Penguin, 2005), pp. 401-403:
The youthful impulse of the Sixties was not about understanding the world; in the words of Karl Marx’s Eleventh Thesis on Feuerbach, written when Marx himself was just 26 years old and much cited in these years: ‘The philosophers have only interpreted the world, in various ways; the point, however, is to change it.’ When it came to changing the world there was still only one grand theory purporting to relate an interpretation of the world to an all-embracing project of change; only one Master Narrative offering to make sense of everything while leaving open a place for human initiative: the political project of Marxism itself.
The intellectual affinities and political obsessions of the Sixties in Europe only make sense in the light of this continuing fascination with Marx and Marxism. As Jean-Paul Sartre put it in 1960, in his Critique of Dialectical Reason: ‘I consider Marxism to be the unsurpassable philosophy of our time.’ Sartre’s unshaken faith was not universally shared, but there was general agreement across the political spectrum that anyone wishing to understand the world must take Marxism and its political legacy very seriously. Raymond Aron—Sartre’s contemporary, erstwhile friend and intellectual nemesis—was a lifelong anti-Communist. But he, too, freely acknowledged (with a mixture of regret and fascination) that Marxism was the dominant idea of the age: the secular religion of its epoch.
Between 1956 and 1968 Marxism in Europe lived—and, as it were, thrived—in a state of suspended animation. Stalinist Communism was in disgrace, thanks to the revelations and events of 1956. The Communist parties of the West were either politically irrelevant (in Scandinavia, Britain, West Germany and the Low Countries); in slow but unmistakable decline (France); or else, as in the Italian case, striving to distance themselves from their Muscovite inheritance. Official Marxism, as incarnated in the history and teachings of Leninist parties, was largely discredited—especially in the territories over which it continued to rule. Even those in the West who chose to vote Communist evinced little interest in the subject.
At the same time there was widespread intellectual and academic interest in those parts of the Marxist inheritance that could be distinguished from the Soviet version and salvaged from its moral shipwreck. Ever since the Founder’s death, there had always been Marxist and marxisant sects and splinter groups—well before 1914 there were already tiny political parties claiming the True Inheritance. A handful of these, like the Socialist Party of Great Britain (SPGB), were still in existence: vaunting their political virginity and asserting their uniquely correct interpretation of the original Marxist texts. But most late-nineteenth-century Socialist movements, circles, clubs and societies had been absorbed into the general-purpose Socialist and Labour parties that coalesced in the years 1900–1910. Modern Marxist disputes have their roots in the Leninist schism that was to follow….
The exhumation of the writings of Luxemburg, Lukacs, Gramsci and other forgotten early-twentieth century Marxists was accompanied by the rediscovery of Marx himself. Indeed, the unearthing of a new and ostensibly very different Marx was crucial to the attraction of Marxism in these years. The ‘old’ Marx was the Marx of Lenin and Stalin: the Victorian social scientist whose neo-positivist writings anticipated and authorized democratic centralism and proletarian dictatorship. Even if this Marx could not be held directly responsible for the uses to which his mature writings had been put, he was irrevocably associated with them. Whether in the service of Communism or Social Democracy, they were of the old Left.
The new Left, as it was starting to call itself by 1965, sought out new texts—and found them in the writings of the young Karl Marx, in the metaphysical essays and notes written in the early 1840s when Marx was barely out of his teens, a young German philosopher steeped in Hegelian historicism and the Romantic dream of ultimate Freedom. Marx himself had chosen not to publish some of these writings; indeed, in the aftermath of the failed revolutions of 1848 he had turned decisively away from them and towards the study of political economy and contemporary politics with which he was henceforth to be associated.