Based on novels written in Modern Standard Arabic published between 1963 and 2005 and from the entire Arab world, this article suggests how the hypothetical systems of this variety of language no longer correspond to the established "classical" model. Specifically, it demonstrates that the so called MSA grammar books are, facing the reality of the texts, descriptively inadequate. It then shows how the modern Arabic conditional clause, in its literary level, has created a kind of sequence of tenses, certainly influenced by European languages such as French and English. Therefore this is no longer the operator of the hypothetical system (iḏā, in and law) that enables us to understand the meaning of a conditional clause, but the relationship existing between the operator of the hypothetical system's protasis and the verbal form of the apodosis of that system.