Gilles Kepel is a towering figure and in some ways a tragic one. He spent some two or three years in Egypt at the beginning of the 1980s. Then he brilliantly defended a PhD on Egypt's Islamists during the Sadat era — a pioneering work that is now out of date. In 1984 or 85, he was appointed to the newly created Arab Studies Department in Sciences Po, Paris. He taught dozens, maybe hundreds, of future specialists. French and European universities, media organisations and administrations are replete with his former students. But for many reasons, he never felt secure and legitimate; a fact that partly explains his bad relations with his colleagues. Intelligent, with an acute political flair, he always tried to strike a balance between “what he knows” and “what the people want to hear”. He wanted academic recognition and popularity with the public. He deserves both but has a lot of enemies who resent his controversial behaviour. Moreover, he does not share academia's ideology and beliefs. He is a brilliant mind but has a sombre character with self-destructive tendencies. Kepel, maybe rightly, saw in Olivier Roy's celebrated paper “Islamisation of Radicality” a direct attack on his research on French suburbs (he focussed on this in the second half of the 1980s and recently returned to it). And he — with his former pupil Bernard Rougier, a top expert on Salafism — replied violently. To say he focussed on the “supply”, not on demand, is to simplify the issue. He basically said that Roy's approach — emphasising the existence of a Western demand for radicality that has nothing to do with Islam and should accordingly be analysed as a reaction to Western societies' ills — was widely missing the mark. For Kepel, jihadism was not a “normal” form of radicality but a specific one, radically different from previous radical ideologies. To understand it — and its novelty — one should be able to read Arabic and understand Muslim theology. This is, of course, a personal and not so elegant attack against Roy. He named him and said he gave weapons to those who did not want to see facts. But the Kepel/Roy polemic is also the new form of an old debate on the relevance of what the players say. And it is also a debate on the definition of the main issue: Is it Western societies' ills? If the answer is “yes”, what are these ills? Is it the struggle for Islam's future and for Muslim integration in European communities? Or is it “the relation between jihadism, Salafism and Wahhabism”? Kepel and Rougier said “radicality” was too vague a notion encompassing widely different things. It was an easy way to placate those who were afraid of the spread of Islamophobia and to sideline the need to study Islamic thought. It exempted scholars from studying the poor suburbs and the development of Salafist ideas there. “Radicality” was not only too vague it also was American (in France, this is not a compliment). “Radicality”, as used by Americans and their French clients, told a simple — and presumably stupid — story: an individual, without specification (religion, class, sex, culture, language, etc), experiences a frustration and decides to rebel. He therefore looks for an ideology legitimising rebellion. A terrorist cell brainwashes him and he becomes one of them. This is a story that can spare us the need to learn the language, the culture, the religion, the social structure, etc. It allows self-proclaimed “experts” — people who know nothing about Islam, who do not speak Arabic — to become experts on this new version of radicalism. The taxpayers' money should not be used to fund such fake experts, it was inferred. It should finance serious ones who study Arabic, Islamic thought and fiqh, the history and evolution of jihadist movements (which emerged long before the rise of the Internet and Facebook), and of course social structures and communities. Many people tend to dismiss this criticism. It is too well tailored to target Roy, to be honest. Roy studies what is said on the net, not in mosques; his command of Arabic is inferior to Kepel's. He said in a previous and most brilliant book (Holy Ignorance) that the new fundamentalisms no longer have links with a country's or a religion's culture, and he never systematically worked on jihadism. Moreover, many people suspect Kepel's intentions: he never writes what he believes; he is supposed to have a strong dislike for religions, etc. Last but not least, to say Roy scorns the study of social structures and discourses is unfair. Kepel may be unfair to Roy, but we should not reciprocate. His response to Roy asks serious questions that deserve thorough examination. He is right on many counts: jihadism is a radically new form of radicalism that has some features in common with the left-wing terrorism of the 1970s, but also significant differences. Neither the societies nor the terrorists are those who clashed during the 1970s. The new fundamentalism owes a lot to modernity, or to post-modernity, but that does not mean it has no links with religious tradition, even if it does not understand it. Terrorism went global: Western societies' ills have to be studied but jihadism's history and its complicated relation with the “Islamic universe” in general — and with Salafism in particular — are also relevant. The writer is a professor of international relations of the College de France and visiting professor at Cairo University.