Such confusion is also evident in God's Crucible, an account of Islamic-Christian warfare over the course of some seven centuries. Although occasionally vivid and exciting, God's Crucible is essentially a case of a stirring narrative in search of a theme. The nearest Lewis comes to finding one is when he argues that the Franks were wrong to resist a Saracen incursion in 732. If the Moors had prevailed at the Battle of Poitiers (or Tours, as it is also known), Europeans not only would have been exposed to astronomy, trigonometry and Greek philosophy--all of which Muslims knew but Christians did not--but also would have gained entrée to "a cosmopolitan, Muslim regnum unobstructed by borders...one devoid of a priestly caste, animated by the dogma of equality of the faithful, and respectful of all religious faiths." Indeed, Lewis calculates that they would have leapt ahead by exactly 267 years, nearly to the year 1000, that is. But since it was the Franks who won, Europe was doomed to continue on a path that God's Crucible characterizes as "economically retarded, balkanized...fratricidal." By "defining itself in opposition to Islam," Lewis writes, Europe wound up making a virtue "out of religious persecution, cultural particularism, and hereditary aristocracy." The result, it would seem, has been religious warfare, riots in Parisian banlieues and rising levels of economic inequality. Evidently, we're still paying the price.
It would be nice to report that Lewis, a professor at NYU and the author of a Pulitzer Prize-winning biography of W.E.B. Du Bois, is being satirical in suggesting that the West would have been better off going Muslim. But he is all too serious. Perhaps hearing a long line of historians from Edward Gibbon to Victor Davis Hanson describe Charles Martel's triumph at Poitiers as a victory for civilization got Lewis's dander up to the point that he decided to write a book saying the opposite. In any event, the basic problem with God's Crucible has to do with the linkage of Islam and cultural advancement, a connection Lewis seems to regard as so simple and self-evident as to render further thought unnecessary. Since tenth-century Córdoba was a large and glittering city--"the brilliant ornament of the world," in the judgment of a visiting Saxon nun named Hroswitha of Gandersheim--at a time when Paris was little more than a country town, then, no doubt about it, it was the Muslims who were ahead and the Christian Franks who were behind.
What Lewis fails to recognize is that while a society can be deficient in some respects, it can be advanced in others that eventually prove more important, even if the benefits are not immediately apparent. Lewis points out that the caliphate had a sophisticated system of taxation while the Franks had virtually no tax system at all. But the absence of a tax system was a relief to the peasantry, since it meant that the economic burdens on them would remain comparatively light. He notes that the Muslim emir Abd al-Rahman I had a sophisticated army at his command, whereas all Charlemagne had was a promise from his nobles to assemble every spring with their horses, armor and weaponry. But Rahman I's army was a slave force, whereas Charlemagne's was free, which is no doubt why the Christian side eventually came out on top.
Lewis further notes that gold coinage had disappeared from Western Europe, especially the portion of Northern France controlled by the Franks; that trade had come to a near standstill; that spices, jade and other imported luxuries "were dimmest memories"; and that the Western European economy had cut itself off from "the Mediterranean engine that had once quickened it." This is all quite true. But he also observes that "food, however, was plentiful" in the Frankish territories, that cattle breeding had improved and that production of brine-preserved fish "made for an energy-fueled diet sufficient to grow the big-boned frames of the typical blond Frank warrior." The question, which he does not address, is what one had to do with the other, what a decline in trade had to do with a rising level of agricultural productivity.
Very much, in fact. In pulling away from the Mediterranean, Northern Europe was indeed closing in on itself. Economic isolation of this sort did not result in economic decline, as Lewis all too readily assumes, but in what sociologist Michael Mann describes as a process of economic intensification. As trade contracted, lords and peasants turned their attention to raising output on their estates and plots of land. Since rents were comparatively low and taxes nonexistent, peasants had an incentive to boost productivity. Humble but important technological innovations began to spread as a consequence: the water mill, the heavy iron plow, the three-crop rotational system (which allowed each field to be used a third more often), plus the horseshoe, the horse collar and more efficient types of harnesses. The upshot was more effective use of animal power, more efficient transport and, from the ninth century through the early thirteenth, a doubling in crop yields, a breakthrough that economic historian Georges Duby has rightly described as the first great agricultural revolution.
Frankish society was rude and unpolished, in other words, but economically dynamic. It was also, relatively speaking, free. Whereas slavery on the northern side of the Pyrenees essentially disappeared by the eleventh century, it remained as widespread as ever on the other. The balkanized European power structure that Lewis decries was equally a two-edged sword. It was inefficient, certainly, but also made autocracy unthinkable. Indeed, that is why Charlemagne's empire ultimately collapsed. The Byzantine political methods that he imported failed to work amid the highly complex structures of the West.
What would have happened if the Muslims had prevailed at Poitiers and then marched to Paris? Assuming they imposed their social system on the Franks' realm rather than looting and moving on, the results might well have been a victory for civilization. But it would have been civilization of a highly autocratic type. Detaching itself from the Mediterranean turned out to be the best thing European society could do, because it ended up charting a different course. Lewis is right to be outraged by the sort of Eurocentric arrogance that leads to denigration of the Muslim world's legitimate cultural achievements. But an equal and opposite Islamocentrism is no less absurd. Whereas his goal is to heal the breach between Islam and the West, the real task is to come up with a revivified Enlightenment frame of reference that renders the entire split irrelevant.