Louis Althusser sounds like an anagram, which is fitting because his books read like clues to a crossword so cryptic it would have defeated Alan Turing. In the introductory note to History and Imperialism its editor and translator, G.M. Goshgarian, talks of “a certain carelessness of expression” in Althusser’s work, adding that “Marx and History” “is the only one of these writings to have been seriously revised”.

Revised? Seriously? Here is a sentence from that essay: “The dialectic is the play that the last instance opens up between itself and other ‘instances’, but this dialectic is materialist: it is not played out up in the air, it is played out in the play opened up by the last instance, which is material.”

And after a carelessness of expression like that, you get a carelessness of expression like this: “In its form, the topography is something other than a Description of distinct realities, something other than a Prescription of the forms of determination: it is also a register of Inscription and thus a positioning mirror for the one who states it and the one who sees it.” Nietzsche said that once something is clear to us, it ceases to be of interest. Althusser wrote prose so cloudy you’d have to be barmy to be interested in the first place.

Althusser himself was an out and out whack-job. Back in 1980 the then 62-year-old philosophe stumbled from his rooms at the École Normale Supérieure howling for the duty doctor. A terrible accident had occurred. While “massaging [his despised wife] Hélène’s neck”, Althusser had slipped into a reverie. When he came round, Hélène’s eyes were glazed over and her tongue hanging from her mouth. Les flics were summoned to the scene.

Althusser was marched off, though he wasn’t charged with murder, or even manslaughter. Instead, he was taken to a psychiatric hospital where, after being pronounced insane and therefore unfit to stand trial, he was confined for several years. During that period it emerged that Althusser had been severely depressed for much of his adult life. He had spent almost as much time in the asylum as he had lecturing at the École. Even after his release, he chose to spend the bulk of the years left to him (he died of pneumonia in 1990) voluntarily incarcerated.

Following Hélène’s death, Althusser published no more books of philosophical/political theory. But after his death a memoir came out in which, in best Freudian style, he blamed what had happened on his upbringing. His mother’s first love, after whom he was named, had perished in the First World War. Subsequently, she married the man’s brother, who went on to father young Louis. Alas, Althusser says, he never got over having been named after a dead man. It had led, he said, to his lifelong sense of “not existing”. Worse, since in French “Louis” is pronounced exactly the same as the word for “he”, he had never thought of himself as an individual proper.

It’s possible, I suppose, that Louis believed this hooey. But if he did, how did he square it with the structural Marxism that made his name? A reaction to the existential Marxism that had ruled the roost for several years in post-war Paris, structural Marxism held that all talk of an individual self was so much liberal bourgeois humanist wind. Where Sartre and Co had argued that existence precedes essence — basically, that there’s no such thing as human nature and that we make ourselves up as we go along — Althusser went the whole hog and denied the existence of essence.

The guy who found fame with books called For Marx and Reading Capital, had read about as much Marx as Margaret Thatcher had

There was, he said, no such thing as human nature, and therefore no such thing as the human condition. Human beings, he wrote, “are not ‘free’ and ‘constitutive’ subjects”. Rather, “they work in and through the determinations of the forms of historical existence of the social relations of production and reproduction”. The idea of human agency, in other words, is just that — an idea. Forget false consciousness — consciousness itself is a falsehood. It follows, he said, that history is “a process without a subject”. If this sounds familiar, that is only because Althusser did not invent determinism.

He invented a lot else. He had to. He’d done precious little of the donkeywork required of a professor of philosophy. As he admitted in that posthumously-published memoir, though he’d been the École’s go-to guy for counsel on the most abstruse philosophical ackamarackus, he’d actually been winging it for years. He hadn’t, it turned out, read all that much. “I knew the work of Descartes and Malebranche well,” he wrote, before descending into a more confessional mode: “Spinoza a little, Aristotle not at all . . . Kant not at all, Hegel a little.” A little is right. For his thesis on Hegel, Althusser actually made up quotations that were never spotted by his tutor, Gaston Bachelard.

Above all, though, Althusser was unfamiliar with the bulk of Marx’s work. That’s right. The guy who found fame with books called For Marx and Reading Capital, had read about as much Marx as Margaret Thatcher had. Though he followed Bachelard in arguing that The German Ideology represents an “epistemological break” in Marx’s thought (as it does: it’s the book in which Marx abandons Hegelian idealism), Althusser later admitted that he was unsure how he’d arrived at that conclusion because the only bits of Marx he’d glanced at all predated The German Ideology.

Nothing daunted, he set about reinterpreting Marx anyway. Hitherto, he argued, Marx had been misunderstood. Far from being a historian and political philosopher, Marx was a scientist. Far from being a set of ideological claims, Marxism is a description of the workings of the world. There is nothing contingent about it. Like physics, like chemistry, like biology, it is a method for exploring and explaining life as it is, was, and ever shall be. Unlike you and me, who are, remember, only the impotent puppets of whatever moment we find ourselves born in to, Marxism exists outside — indeed, is independent of — history.

Such positivist fealty would be alarming even if it countenanced the work of Karl Popper. But it doesn’t. Popper is mentioned just twice in History And Imperialism — both times dismissively — and you will seek his name in vain in the rest of Althusser’s work. This is strange, because the idea that crops up most in this book (“science”) is the subject of one of Popper’s most famous works, The Logic Of Scientific Discovery. Then again, since Popper’s take on the subject — that we should talk not of eternal, unchanging scientific laws but of provisional, contestable scientific theories — is diametrically opposed to Althusser’s naive certitude, its omission is perhaps explicable.

The heart of this new collection is meant to be Althusser’s “Book on Imperialism”, though calling it a book is a bit of a stretch. In fact, it’s little more than a random collocation of unargued asides — Marxism “provides, through experimentation, objectively proven results that are incontestable (except for those who, for class reasons, do not care to see them)” — and you’ll learn far more from a page of George Lichtheim’s Imperialism than you will from almost a hundred of Althusser. Elsewhere, we get “A Conversation on Literary History” (a sub-Barthesian ramble around the concept of authorship in which the work of I. A. Richards is tossed around with regal incomprehension), and a clutch of what Goshgarian calls “outlines and drafts; an informal talk posing as improvised remarks recorded by happy accident; and notes on particular points reserved for a small circle of insiders”, all of which were “left . . . in a drawer”. Slim pickings for even the most devout Althusserian, in other words.

Not that there are many of those left. Althusser’s ideas never held sway in university history departments, where an emphasis on evidence-backed claims and a disapproval of monocausal explanations meant any kind of theory found it hard to gain traction. He had a bigger impact in English departments, where his pseudo-scientific liturgy helped students and lecturers kid themselves

They’d stopped talking impressionistic guff about stories. For two generations before Althusser, literature students had been encouraged to discuss characters in fiction as if they were real people. After Althusser, they began to talk about real people as if they were fictional constructs.

Who knows? At some point in the future scientists might prove that we are all living in The Matrix. Until such proof arrives, though, we must go on believing that other people do exist, and that by and large they have the same needs and wants as we do, lest the death camps loom once more. “The awful thing about life,” said Jean Renoir, “is that everyone has his reasons.” Probably the reason Althusser could conceive of man as an abstraction from history was his insanity. The rest of us — even those of us deranged by History And Imperialism’s oracular gibber — have no such excuse.