Perhaps the most stimulating of Gouguenheim’s chapters is the antepenultimate one, under the title of “Problems of Civilization.”

Medieval Islam,” Gouguenheim notes, “had not developed any real curiosity for societies exterior to it.” While the magnum opus of Persian literature, The Thousand Nights and a Night, saw its first European translation early in the Eighteenth Century, neither the Iliad nor the Odyssey ever interested any Muslim translator. “This absence of curiosity explains in part why the Middle Ages seem to comprise a paralyzing confrontation of several centuries, more often violent than peaceful, which the shared monotheistic belief better sustained than it ameliorated.”

But the notion of a common monotheism, while hopeful, might be misleading:

To proclaim that Christians and Muslims have the same God, and to hold to that, believing thereby that one has brought the debate to its term, denotes only a superficial approach. Their Gods do not partake in the same discourse, do not put forward the same values, do not propose for humanity the same destiny and do not concern themselves with the same manner of political and legal organization in human society. The comparative reading of the Gospel and the Koran by itself demonstrates that the two universes are unalike. From Christ, who refuses to punish the adulterous woman by stoning, one turns to see Mohammed ordaining, in the same circumstances, the putting to death of the unfaithful woman. One cannot follow Jesus and Mohammed.

Christianity was ready, moreover, to receive, not only the philosophy, but also certain basic political principles, of the ancient Greeks, particularly of the Athenians, such as “liberty, reason, and democracy.”