The House of Wisdom (29 page)

Leonardo’s work came to the attention of Michael, who sent the mathematician a detailed commentary, including proposed changes and corrections to
The Book of Calculation
. Michael also ensured that the Italian scholar would have the backing of the emperor, who delighted in Leonardo’s ability to solve mathematical puzzles that had stumped some of the leading Arab experts with whom Frederick was in regular correspondence. A later edition of
The Book of Calculation
thanks Michael on both scores: “You, my Master Michael Scott, most great philosopher, wrote to my Lord [Frederick II] about the book on numbers which some time ago I composed and transcribed to you; whence complying with your criticism, your more subtle examining circumspection, to the honor of you and many others, I with advantage corrected this work … Further, if in this work is found insufficiency or defect, I submit it to you for correction.”
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Leonardo produced major treatises on geometry, second-degree equations, and the practical needs of a growing international mercantile class—converting multiple currencies, allocating shares in commercial partnerships, working with varying units of measure—and he anticipated the coming use of decimal fractions. In an unusual departure from the conventions of his day, Leonardo omitted references to mystical numerology, and he was more than willing to acknowledge Arab contributions to his art.
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“In solving problems there is a certain method called ‘direct’ that is used by the Arabs, and that method is a laudable and valuable method, for by it many problems are solved.”
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A number of his books addressed in detail some of the very puzzles that Frederick had posed to him and other contestants in court-sponsored mathematics tournaments, but none enjoyed anything like the popularity accorded the more derivative
Book of Calculation
.

Leonardo also developed what has come to be known as the Fibonacci sequence, based on his solution to a puzzle on the breeding fortunes of rabbits.
The Book of Calculation
poses this riddle as follows: “A certain man had one pair of rabbits together in a certain enclosed place, and one wishes to know how many are created from the pair in one year when it is the nature of them in a single month to bear another pair, and in the second month those born to bear also.”
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The resulting pattern of numbers Leonardo generated in his solution has been found to address an entire range of scientific and mathematical problems. Today, application of this famous sequence is the subject of its own scholarly journal, the
Fibonacci Quarterly
, and it has been used for decades by technical market analysts trading stocks, bonds, and other instruments.

Frederick’s reign—he was crowned in 1198 as a boy of four and died in 1250—marked an important way station in the West’s long journey toward the great scientific advances of the seventeenth century. Perhaps unique among contemporary European rulers, this second of the “baptized sultans” sought to ground his worldview in reason, a hallmark of the coming scientific method. This approach was at the heart of the emperor’s decision to abolish trial by ordeal—the same system of justice once ridiculed by Usama ibn Munqidh, the Syrian commentator on the early crusaders. It was, Frederick concluded, a method that did not lead to truth and could not be justified by reason.
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In an original treatise on falconry, Frederick goes well beyond a somewhat cursory study one hundred years earlier by Adelard of Bath by incorporating material from Arabic sources as well as the latest translations by Michael Scot of Aristotle and Avicenna on zoology. For example, he introduces to the West the Arab practice of hooding falcons, and he turns to Egyptian experts for an attempt to incubate ostrich eggs with the heat of the sun.
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Like Adelard, he has freed himself from the “halter” of authority; al-Emberor was more than prepared to correct no less an authority than Aristotle whenever his own observations or extensive experience with falcons demanded it.
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Frederick writes with the same note of intellectual self-confidence that would later prevail more broadly in the West: “Our work is to present things that are as they are.”
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Few of his contemporaries were sympathetic to his scientific bent and reliance on reason. Pope Gregory IX, who battled Frederick for power and influence at every turn, bitterly accused the emperor of disregarding church teachings and, by extension, papal authority by accepting only that which could be proved by rational thinking.
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Popular tales—some concocted by his many enemies, such as the thirteenth-century Franciscan monk Salimbene, who detested the emperor—cataloged Frederick’s supposed scientific excesses. One held that the monarch had ordered that infants be raised in total silence in an effort to learn whether they would grow up to speak Hebrew, thought of at the time as man’s “natural” language. In another episode, we are told, the emperor directed that a condemned man be allowed to suffocate in a sealed room, which was then opened carefully to see if his soul had escaped after death.

Frederick was also a voracious reader, ready to take what he needed from scholars of different traditions or faiths, whether Muslim, Jewish, or Byzantine Christian, with an openness that clearly shocked the staid churchmen back in Rome. The fear of change that for centuries had effectively paralyzed the collective intellect of the Christian Middle Ages was remarkably absent in Frederick’s makeup.
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By his own account, he had been eager for knowledge since childhood, “inhaling tirelessly its sweet perfumes.” That same open and inquisitive nature, colored by a certain unbridled enthusiasm and scattershot quality of mind, informed the so-called Sicilian Questions, a rambling series of philosophical, metaphysical, and scientific questionnaires that Frederick enthusiastically forwarded to his large network of mostly Arab scholars. “Tell us … just where are hell, purgatory, and the heavenly paradise, whether under or on or above the earth?”
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Frederick asked his correspondents. Other topics had to do with optics—why did an object appear to bend when partly immersed in water?—and the size and structure of the universe.

Some Arab respondents had their doubts about the depth of Frederick’s understanding of philosophical matters, yet the fact remains that the emperor was an important figure in the scientific development of the West—not least because he exhibited a new spirit of inquiry and cultural receptivity that broke with centuries of self-imposed intellectual isolationism. His Sicilian Questions prefigured one of the major battlegrounds for the conflict between traditionalist Christian theologians and a new generation of Western philosophers, inflamed by the works of the leading Arab thinkers: “Aristotle the sage in all his writings declares clearly the existence of the world from all eternity. If he demonstrates this, what are his arguments, and if not, what is the nature of his reasoning on this matter?”
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Earlier, Frederick posed a similar question to Michael Scot. It is not clear whether al-Emberor was satisfied with the answers from his enigmatic science adviser, but there can be no doubt that his intense curiosity about the subject was inspired by the latest in Arab philosophical thinking to reach his court. Here, too, Michael’s hand was crucial, for his reputation for black magic surely pales beside the profound and lasting shock waves from his translations of the works of Abul-Walid Ibn Rushd, the greatest in a long line of eminent medieval Arab philosophers. Ibn Rushd was known to the Latins as Averroes, but his explanations of Aristotelian philosophy were so fundamental to the West’s emerging understanding of science, nature, and metaphysics that he was commonly referred to simply as the Commentator.

The son and grandson of famous Muslim jurists in the Andalusi capital of Cordoba, Averroes could bring to bear both a first-rate Arab education—he was trained in medicine, religious law, and theology and even dabbled in astronomy—and the political acuity gleaned from his family’s long experience in senior state and religious posts. Despite widespread suspicion toward philosophy among the mainstream local clerics, it is clear that Averroes also received competent instruction in the discipline, which had quietly made its way to al-Andalus from the eastern Muslim lands. Following the family tradition, Averroes served as the
qadi
, or religious judge, of Seville from 1169 to 1172, when he was appointed chief justice of Cordoba.

Unable to open the gates of heaven to non-Christians, Dante nonetheless celebrated Averroes by placing him in limbo, alongside Aristotle and members of his “philosophic family.” The Italian poet and philosopher also referred to him approvingly as the one “who made the Great Commentary.” Raphael’s masterful fresco
The School of Athens
has given Averroes a permanent home inside the Vatican’s Apostolic Palace. But it was Michael Scot’s translations, underwritten, transcribed, and forwarded to the universities at Frederick’s command, that did more than anything to bring the Commentator’s comprehensive views on philosophy, particularly his reading of Aristotle, to the immediate attention of the Latin-speaking world.

For Averroes’s Western readers, who tended to take his often-subtle positions to their most extreme conclusions, these works were a revelation. Among his most incendiary philosophical teachings was his insistence on the doctrine of the Eternity of the World, in contradiction to the traditional Muslim, Christian, and Jewish understanding that God made the universe at a time of his choosing and then controlled each and every event in it. After all, Genesis tells us, “In the beginning, God created heaven and earth.” The Christian world, following the lead of the Jews and followed in turn by the Muslims, generally took this to mean the universe had a distinct starting point and was created “from nothing.” Against this, Averroes laid out the Aristotelian view that both time and matter were eternal and that the Creator had simply set the entire process in motion.

Implicit in the teachings of this Arab philosophical tradition was the notion that God did not bother with the details of everyday human life, that he was blissfully unaware of what the medieval theologians called “particulars.” Likewise, God was effectively removed—prevented, even—from day-to-day management of the universe. Instead, he relied on the timeless functioning of universal laws of nature that stemmed from his own perfection. In the eyes of their many critics, such notions contravened the scriptural promise of Judgment Day, when God would personally assess each man’s adherence to the moral code spelled out by revelation. They also raised serious doubts about scriptural accounts of miracles. But they helped create the necessary opening for man to pursue and uncover the laws of existence, otherwise known as natural science.

Centuries earlier, St. Augustine had quipped that a place in hell had been set aside for anyone who dared to ask what God was up to before the Creation.
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But the growing legion of Averroes’s followers in the West would not be put off so lightly. Adelard of Bath had already given the Christian world permission to explore the universe. Now, with the help of Michael Scot, Averroes opened the door to a brave new world. For this Arab thinker, like Aristotle before him, God had created the universe but then left it to man to make his own way through it.

The doctrine of the Eternity of the World has a long history in Christianity. The faith itself was born into a world still very much under the sway of Greek philosophy, and it enjoyed much of its initial success within the Greek cultural sphere. Thus, it was important for the early church to adopt and preserve as much as it could of this rich classical inheritance, particularly where it might be used to support the church’s claim for the truth of Christ’s revelation. However, the problematic issue of the Eternity of the World lay mostly dormant for centuries at a time, obscured by the complexity of the writings of the leading Greek authorities. On those occasions when it was examined, the church fathers and some later Christian theologians effectively conspired to assert, notwithstanding the evidence to the contrary, that there was no real contradiction between scripture and Aristotle’s natural philosophy.
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True engagement with the natural world was possible only once this intellectual fiction had begun to unravel, but first Christendom would have to follow doggedly the trail blazed earlier by the Arab thinkers in their own attempts to harmonize the demands of philosophy with the demands of religious faith. Writing in the ninth century, the philosopher al-Kindi acknowledges his debt to the Greeks. But he also makes it clear that the Arab thinkers were intent on advancing classical wisdom and adapting it to the needs of Muslim culture: “It is fitting then to remain faithful to the principle which we have followed in all our works, which is first to record in complete quotations all that the Ancients have said on the subject, secondly to complete what the Ancients have not fully expressed, and this according to the usage of our Arabic language, the customs of our age, and our own ability.”

Al-Kindi goes on to note that “research, logic, preparatory sciences, and a long period of instruction” are the only way for ordinary people—meaning those who are not blessed by God with prophecy—to attain knowledge.
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This proved of enormous value to the Latin scholars of the late Middle Ages, for much of the debate that later roiled Paris, Oxford, and other centers of church teachings had already been well rehearsed for them. All they had to do was master the Arabic texts and follow along.

The Greek teachings on the origins of the universe are often couched in difficult language and are not entirely without equivocation. Nonetheless, there are passages in Aristotle’s major works that make it clear what he had in mind. Writing in
Metaphysics
, for example, Aristotle says; “There is something which is always moved with an unceasing motion; but this is circular motion. And this is not only evident from reason, but from the thing itself. So that the first heaven will be eternal. There is, therefore, something which moves. But, since there is that which is moved, that which moves, and that which subsists as a medium between these, hence there is something which moves without being moved, which is eternal, and which is essence and energy.”
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This is Aristotle’s famous Unmoved Mover. The full implications of his position—if they were even fully understood at the time—either did not really penetrate the early Christian consciousness or were conveniently ignored.
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