Raymond Geuss would like his fellow philosophers (and many of his fellow citizens) to think about politics in a radically different way. His latest book, Philosophy and Real Politics, is a quietly ferocious broadside against much received wisdom.

Among its targets are "the highly moralised tone in which some public diplomacy is conducted, at any rate in the English-speaking world, and ... the popularity among political philosophers of the slogan 'Politics is applied ethics'." What this slogan usually means in practice is starting off with abstract general principles or intuitions about fairness, justice, equality or rights, and then applying them to specific political situations. Such an approach, Geuss believes, is unlikely to tell us anything much about the real world of power struggles and messy compromises.

Some of his arguments have their roots in his earliest educational experiences. In a tribute to the philosopher Richard Rorty, Geuss offers an entertaining account of his Roman Catholic upbringing and how it had granted him "relative immunity to nationalism" - and in particular the "patently absurd" notion that there was something "special" about the United States.

For the Irish and Irish-American nuns who taught him from the ages of five to 12, only the Roman Catholic Church was truly universal and international. They knew that all the popes had been Italian, but that was for purely fortuitous reasons. "Only an Italian could stand to live in Rome: it was hot, noisy and overcrowded, and the people there ate spaghetti for dinner every day rather than proper food, ie potatoes, so it would be too great a sacrifice to expect someone who had not grown up in Italy to tolerate life there."

Geuss went on to a Catholic boarding school near Philadelphia where most of the priests and pupils were refugees fleeing the Soviet invasion that followed the Hungarian Revolution of 1956. There he acquired the grounding in German, Latin and Greek that has proved crucial to his intellectual development.

The Church, he was taught, had seen so many empires rise and fall that it was ridiculous to idealise the latest, US, one. This background also meant, he recalls, that he "grew up in a community where the idea of freedom was not at all central". Even now he finds he "can easily imagine a society in which notions such as discipline and self-control play a much more central role". Other philosophers seem to find this more difficult.

Most of his teachers had experienced politics at the sharp end and seen their world fall apart in Hungary. Geuss also acquired "a sense of the shift of larger structures". He describes himself as "conformist but not devout until the age of 15 or 16", when he quietly abandoned Catholicism. As a result, he says: "My life was very compressed in the period from about 1962 to 1968. I went from lukewarm Catholicism to secularism to the student movement on the Left very quickly."

As Geuss got seriously engaged in philosophical studies, they became marked by "a sort of binary formation, partly in New York and partly in Germany, and the part which really 'took', as it were, was the German side". Although his first academic post was as an assistant lecturer in Heidelberg and he later worked at a research institute in Berlin for a year, he nonetheless decided against becoming a fully fledged "German philosopher". While he admires many aspects of the German academic system, he believes "there is a kind of infantilisation of the intellectual life that results from the fact that you have to write a second doctoral dissertation and you're not actually eligible for a permanent position until you've done that. That means you're in your mid-thirties before you have a chance of establishing yourself as an independent person, so there are relations of dependency that you have with older people during your late twenties and early thirties."

Back in the US, Geuss' range of interests left him out on a limb. "I felt completely alienated from professional philosophers. I had no real interest in the things that were of interest to them, yet I also didn't feel that there was any general public that was much interested." Since he "never felt there was anyone I was writing for", he managed to produce only a single 90-page book by his late forties.

Coming to the University of Cambridge in 1993 decisively changed all this. "There were lots of people whose formation was very different from mine," he remembers with gratitude. "But there was a kind of parallel in our interests. Their basic view of the world was formed by studying Hobbes and Locke and other, specifically English, figures. My own formation is Hegel and the Frankfurt School and Marxism. You wouldn't think we would have much in common but it turns out that we had converged, virtually independently of each other, on a certain number of ways of thinking about the political world."

Almost for the first time, Geuss genuinely felt "part of a conversation" and soon started producing a series of major books. Many take what he calls a "genealogical approach" to show how the concepts we take for granted have long and complex histories that make them fall apart on analysis. Public Goods, Private Goods (2001), for example, takes episodes from antiquity - Diogenes the Cynic openly masturbating in the marketplace, Julius Caesar seizing state power to avoid a slight to his dignity - to argue that our usual unreflective distinction between public and private spheres is confused and incoherent.

Clearly a formidable linguist, Geuss is also a published poet. The story of how this happened is curious. "After my father died - this is going to sound terrible - I had these auditory hallucinations of hearing his voice, with its Midwest hillbilly accent that stood out like a sore thumb on the East Coast," he says.

Although a steelworker with little literary culture, the ghostly Geuss senior was reciting Latin poetry his son had studied at school. This led the latter to "look back at all the Greek and Latin literature that I'd read and begin doing some translations and then my own things".

When asked about the themes of his poetry, Geuss paints a fairly bleak picture. "It was mainly dealing with loss, deprivation, disappointed expectation - my youth was almost entirely devoted to disappointed expectation. I never believed that anything promised was going to happen.

"My parents were very poor and my mother was constantly trying to calm us down by saying things such as 'Things will be better tomorrow, we'll have dinner tomorrow, we'll have a sandwich tomorrow', but tomorrow never came. And it never comes. I don't feel that way so much now, but if you grow up with it, it never really leaves you."

Though he makes it sound very gloomy, Geuss' collection of "didactic poems", Parrots, Poets, Philosophers & Good Advice (1999), is full of wit, alcohol and bawdy high spirits. Even when tackling a melancholy topic such as the passing of time, it is in terms of the transformation of "young stud" into "aged codger (with flaccid todger)".

Philosophy and Real Politics develops further Geuss' ongoing reflections on politics and ethics. Two of his favourite whipping boys are the influential American political philosophers Robert Nozick and John Rawls.

The former begins his book Anarchy, State and Utopia with the sentence: "Individuals have rights, and there are things no person or group may do to them (without violating their rights)." He then leaves this thought, Geuss notes with striking irritation, "to lie flapping and gasping for breath like a large, moribund fish on the deck of a trawler, with no further analysis or discussion, and proceeds to draw consequences from it". (Rawls, by contrast, builds his elaborate political theories on his intuitions about the nature of justice.)

On one level, Geuss' book argues that philosophers writing about politics tend to be too abstract and unworldly to be of much use to a union activist or a cabinet minister. This is no doubt true but is hardly news.

But he is also saying something else. "What I find deeply upsetting is the assumption (among many political philosophers)," he explains, "that the political structures that we have are there and that we don't have to think about them. That's the basic idea that Rawls and Nozick have."

Their implicit view, says Geuss, is that "the US political system is there, it's the best thing in the world, and now, given that we've solved all the problems about how to structure a political society, we can tinker with how much money we give to the poor - that's what drives me crazy about it. It's deeply unphilosophical, because the philosopher has to ask big questions and can't simply say, we know what the perfect society looks like - it looks like the United States a little bit cleaned up."

Such thinkers may also have an influence on the real world. Whether or not David Cameron reads John Rawls, he may well have advisers who have been influenced by the styles of political philosophy Geuss deplores. Even if the impact on practical politics is indirect, that doesn't make it any less real or malign. Geuss' own experiences with elite students at Princeton University (many no doubt destined to go into government or administration) rather confirm this.

"I used to teach a course in political philosophy, and I started talking about structures of the state: how states are different from tribes, how a family is different from a corporation, how power is organised in different societies - and students complained about that; they didn't want to hear about it. They thought that political philosophy meant reading people such as John Rawls, doing what everyone else did, looking at our intuitions of justice. That struck me as a terrible impoverishment."

Philosophers in the liberal tradition who "cast an inappropriate glow of invariability upon present society" are particularly irrelevant to current circumstances. "I think that the central liberal thought - the thought about freedom - is probably completely doomed at the moment," reflects Geuss. "I don't think there's a chance in hell that we are going to be able to continue to organise our society around notions of freedom in anything like the way we have. The degradation of the human environment has gone so far that we'll need to move into a world where we subject ourselves to very strict controls. The alternative is massive war about resources."

This may be a pessimistic scenario, but Geuss retains a buoyant sense of the philosopher's true (if often neglected) vocation. "You don't take things for granted, you think about things in the widest possible context. You question them as much as you possibly can, you try to think about their foundations, how things could be radically different - there's a sort of intellectual radicalism built into philosophy."