There was an age when people had the right to criticise the entourage of the prophet, when religious controversy was carried out with a great freedom of tone, and when Islamic scholars glorified atheism. Today, all the many debates relating to Islam present one single dilemma: the abandonment of faith or fundamentalism. In this article, a linguist and a historian relate how the two “givens” of Islam – the integrity of Mohammed’s entourage and the inimitability of the Koran – gradually became established over time. To them, Islam should be reconciled with the science of texts and freedom of thought.