How the French Think: An Affectionate Portrait of an Intellectual People. By Sudhir Hazareesingh. Allen Lane; 427 pages; £20. To be published in America by Basic Books in September.

IN 2003, as America was gearing up for the invasion of Saddam Hussein’s Iraq, a tall Frenchman with a thick silvery mane took the floor at the UN in New York. Dominique de Villepin was then France’s foreign minister, and what marked minds was not only his uncompromising anti-war message, but the way he uttered it: his speech was a magnificent rhetorical appeal to values and ideals. In a deep, silky tone, he spoke for an “old country” that has known war and barbarity but has “never ceased to stand upright in the face of history and before mankind”. As the “guardians of an ideal, the guardians of a conscience”, the UN, like France, he declared, had a duty to plead for disarmament by peaceful means.

There was something quintessentially French about this speech, argues Sudhir Hazareesingh, a professor of politics at Oxford University, who opens his impressive new book with the scene. Mr de Villepin’s words combined “seductive masculinity and rhetorical verve” in the best tradition of French public oratory and linguistic elegance. The speech also appealed to reason, abstraction and logic, framed by binary oppositions: conflict and harmony; morality and power. It hinted at the wisdom both of old civilisations and of France, the national embodiment of universal truth born of historical trauma. And it was expressed with the confident optimism generated by an enduring French sense of historical superiority. What is it about the French, asks Mr Hazareesingh, that makes them think and speak like this?

France is arguably the world’s most self-consciously intellectual country. Public thinkers are cherished like national treasures, given airtime on television and column inches in Le Monde. Their counsel is even heeded. Bernard-Henri Lévy, a contemporary philosopher with an outsized reputation, is credited with a role in persuading Nicolas Sarkozy, a former French president, to intervene in Libya in 2011. As a younger French generation discovered to their defiant delight at a mass march in Paris after the terrorist attacks on Charlie Hebdo in January, French thought is not only about dry stuff to be found in philosophy textbooks; it is a central part of their national identity.

Mr Hazareesingh’s inquiry is partly a dense compendium of such thought from René Descartes onwards. It is not a work for the casual reader, and each chapter is so packed with references and quotations that at times the narrative flow suffers. But Mr Hazareesingh’s main purpose is to examine how, rather than what, the French think: the framework, codes and reasoning that have marked the country’s intellectual expression over the past four centuries.

The author distinguishes five elements to French thinking. The first is the way history is used to structure reasoning, through concepts such as rupture, revolution and progress. Second is the fixation with the nation and collective identity, Mr de Villepin’s rhetoric being a fine example. Third is the intensity of public debate about ideas (“We gossip, we quarrel, we expend our energy in words; we use strong language, and fly into great rages over the smallest of subjects,” wrote Jules Michelet, a French historian, in 1846). Fourth is the importance of the public intellectual as a vehicle for disseminating such ideas. Finally, there is the interplay between rational order and the creative imagination.

As the author notes, many forms of expression considered characteristically French—classicism, belief in scientific progress—emerged well before the 1789 revolution under absolute monarchy. But, for Mr Hazareesingh, “most of the fundamental arguments among the French…continued to revolve in one way or another around [the] Revolutionary heritage.” The long shadow of the revolution shaped the fundamental notion of rupture: ideas, artistic movements, theoretical constructs or even political movements, are to be doubted, critiqued and destroyed.

Over time, this reflex has been a source of both creativity (the nouvelle vague; the nouveau roman) and instability (the 1871 Paris Commune; May 1968). The author makes the case for long cycles of thinking on both the left and the right: 20th-century communism and Gaullism echoed, respectively, Jacobin and Bonapartist traditions. He is good, too, on how rupture has both animated and fractured the left over history, with the prevailing belief that “political change could be meaningful only if it was comprehensive and cleansing.” Radical rhetoric still informs the Socialist Party, despite its split from communism back in 1920 after disagreement over allegiance to Lenin’s Third International.

Mr Hazareesingh is less convincing at the end of the book when examining the declining influence of French thinking today. He rightly notes a “loss of confidence by the French in the creativity of their thinkers” since the era of Jacques Derrida, Michel Foucault, Jean-Paul Sartre and Albert Camus. And he is scathing about today’s cultural conservative thinkers, with their links to resurgent ethnic nationalism. He also documents the fading influence of French thought on the rest of the world, though he has oddly little to say about the best counter-example, Thomas Piketty, an economist whose book, “Capital in the 21st Century”, recently took English-speaking countries by storm. The author dismisses his discipline as a “technical field”.

Despite the evidence he marshals to the contrary, Mr Hazareesingh seems to not want to believe that French intellectual influence is in retreat. France may no longer have great thinkers, he writes, but at least it still has lots of people who think and publish lots of books each year, as if quantity somehow makes up for it. Perhaps the author is swayed by an evident and understandable affection for the country and its culture. But a satisfying explanation for this decline, and for its accompanying collective pessimism, deserves another volume to itself.