The Caliphate of the Islamic State developed a complex system of online argumentation that mediated and spanned the whole spectrum of jihadist literacy, from glossy magazines to short messages on social networks, from combattant letters to multimedia postings, and from chants to battle-field harangues and sermons. The overall effect was “terrifying” in the etymological sense of the word as arguments served to establish a unique intellectual “territory” that redoubled the physical one. It was molded by a sustained rhetoric that incorporated (...) traditional juristic or theological modes of reasoning, and verbal/visual artefacts. It created an argued literacy meant to endure after the loss of territory. This essay details the various argumentative components of this literacy while questioning the knowledge “we” have of it. (shrink)