The House of Wisdom (33 page)

For Thomas, only a few areas were off-limits to philosophy, and then only because man could never hope to penetrate the mysteries of the divine will. He found just three articles of faith that could not be proved by reason and that had to simply be accepted by all Christians: God’s creation of the world at a specific time; the Trinity; and Jesus’s role in the salvation of mankind.
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By implication, virtually the entire natural world and even what might appear to be traditional theological questions—for example, regarding God’s existence—were proper subjects for the philosophers and could be adjudicated by reason. For Thomas, as for Averroes before him, philosophy and religion could never truly contradict each other.

In his unfinished masterwork,
Summa theologiae
, Thomas returns to the Eternity of the World to argue that preserving the separate realms of science and revelation is imperative to protect Christian faith: “That the world had a beginning … is an object of faith, but not of demonstration or science. And we do well to keep this in mind; otherwise, if we presumptuously undertake to demonstrate what is of faith, we may introduce arguments that are not strictly conclusive; and this would furnish infidels with an occasion for scoffing, as they would think that we assent to truths of faith on such grounds.”
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At the time of Thomas’s death, in March 1274, there was certainly no sign that his monumental effort to harmonize faith and reason—an effort guided by the spirit of Averroes, tempered by Christian tradition—would outlast the tumultuous decade, let alone one day become the teaching of the Catholic Church. Many of his fellow theologians were aghast at this “natural theology.” The more prescient recognized that Thomas had opened the way to almost unbridled philosophical speculation, and they feared deeply what might come next.

The Franciscans, no doubt driven by conviction as well as by their historic rivalry with the Dominicans, led a furious assault on Thomas. They helped engineer a new round of condemnations—the fiercest ever—on the third anniversary of his death, which took aim at Thomas in spirit, although not in name. They also produced a polemic,
The Correction of Brother Thomas
, and included it in the order’s curriculum. At Paris and at Oxford, a Franciscan stronghold, several masters sympathetic to Thomas’s views were persecuted or excluded from teaching. The Dominicans fired off a treatise of their own in defense of their champion and made his work part of their own course of studies. However, Thomas Aquinas’s views gradually prevailed at the highest levels of the church, and he was canonized in 1323. Two years later, church officials in Paris formally cleared St. Thomas of any heresy in connection with the condemnations.

The internal battle over Thomas’s legacy, however bitter, was not the only worry facing the church. The era had also seen the emergence in Paris of a powerful new generation of secular intellectuals, led by the street fighter turned metaphysician Siger de Brabant. As a young student, Siger was the leader of the Picard nation, a student association that literally fought for the interests of the natives of the Low Countries. Brawls with the royal gendarmes and members of the three other “nations”—the French, the Normans, and the English, which included the large German contingent—were a regular feature of student life along the Street of Straw, and Siger was instrumental in some of the worst of the fighting. At one point, he was on the verge of expulsion for his part in the kidnapping of a French rival. Nevertheless, he managed to secure his master of arts degree by 1265 and became an instructor at the faculty of arts.

Siger immediately turned his combative spirit, as well as his impressive intellect, on the more orthodox colleagues in his own department and on the faculty of theology. Like Averroes, Siger and his supporters saw the pursuit of philosophical truth as the supreme human endeavor. But the members of this circle, while devout Christians all, were indifferent to the religious implications of their philosophizing. Instead, they set out to establish a firm distinction between philosophy and theology, each with its own methods and its own concerns.

In the eyes of the hard-liners in Paris, fed up with these upstart Averroists and already leery of the direction in which Thomas was seeking to take the church, such independence of mind was the arts masters’ greatest sin. The thirteen condemnations of 1270 had been a warning shot in response to the militancy of Siger, who by now had a significant following among the arts students, but like previous church bans they had had little effect. The next year, Siger led a breakaway faction of masters who refused to accept defeat in elections for a new rector of the arts faculty. The dissidents effectively created their own parallel department, named their own rector, and awarded their own arts degrees.
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Meanwhile, the orthodox majority in the arts faculty took an oath not to discuss theological matters in their classrooms. The pope’s personal representative, the papal legate, finally intervened in 1275 to confirm the elected rector, and Siger left the university for good. Soon teaching in private anything except grammar and logic was also banned, suggesting that discreet study of illicit material had been rampant.

The church was not done with the rebels. Siger and two colleagues were summoned to appear before the Inquisition on January 18, 1277, to face charges of heresy. However, there is no record of any convictions, suggesting that all three were eventually acquitted. Three months later, the bishop of Paris published his infamous list of 219 condemned propositions, the same compilation that indirectly implicated Thomas Aquinas. Among the allegations against the arts masters was adherence to the Double Truth: “For they say these things are true according to philosophy but not according to the Catholic faith, as if there are two contrary truths and as if the truth of the Sacred Scripture were contradicted by the truth in the sayings of the accursed pagans.”
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These condemnations of 1277, drafted by a committee of church bureaucrats, paint a curious and often distorted portrait of the intellectual scene in Paris. Yet they reveal the anxiety among the ecclesiastics that they were losing the intellectual high ground to the secular philosophers and their Arab mentors. Almost a dozen “errors” on the bishop’s list concern the Arabs’ notion of the Eternity of the World, with the authors of the bans also insisting, against the teachings of Thomas Aquinas, that Creation in time can be proved by reason. Several entries reflect the church’s deep concern with determinism, inherent in Arab astrology’s link between celestial activity and events on earth. Still others condemn accepted Christian positions, or else they hopelessly mangle the controversies of the day beyond recognition. In places, the banned propositions read like taunts between playground rivals; for example, the masters are specifically proscribed from asserting “that there is no more excellent state than the study of philosophy” and “that the only wise men in the world are the philosophers.”
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The tragic and talented Siger—one of his students called him “the most distinguished teacher of philosophy”
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—never returned to the lecture hall. In truth, his views had never strayed far from those of Thomas, whom he had clearly read and admired, but his unyielding insistence that the philosophers go where reason took them, an early defense of intellectual freedom, cost him his career and possibly his life. A chronicle from his native region of Brabant tells us that he died at the hands of a crazed cleric: “This Siger, a Brabantine by birth, as a consequence of holding certain opinions against the faith, was no longer able to remain in Paris, and went to the Roman court, where after a short while he died of stabbing by his half-mad secretary.” The date of his murder must have been sometime before November 1284, when a letter from the archbishop of Canterbury makes mention of his death.
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The condemnations of 1277 dampened enthusiasm in Paris for rationalist speculation and natural philosophy, but they failed to weed out the influence of Thomas, or that of Averroes and his pugnacious acolyte, Siger de Brabant. The locus of scientific and philosophical activity in many cases simply shifted elsewhere, and the influence of the Averroist tendency took root as far away as Poland and England. Theology historically enjoyed little prestige or influence at the Italian universities, such as Padua and Bologna, and Averroes’s teachings flourished there into the seventeenth century. Even at Paris, it was not so long before such matters were again openly read and debated. The men of science were clearly here to stay.

It is tempting to attribute their success to the raw power of natural philosophy and to the inability of the church to stamp out this competing “theory of everything” in the same way it had destroyed the Cathar heresy. Yet to do so is to overlook the crucial role of the Arabs as master architects—not simply as midwives—of the emerging Western worldview. This was no mere “recovery” of classical wisdom by the medieval Latins, with the Arabs cast in the role of benevolent guardians, as most Western histories of the period tell us. Rather, it represented the enormous transfer—some might even say cultural theft—of invaluable Arab knowledge and technology directly to the Christian West.

The case of Aristotle’s natural philosophy is but one prominent example of the Arab influence at work. The great philosopher never had much time for God, and certainly did not conceive of a deity like the one who governed the monotheistic faiths of Judaism, Christianity, and Islam. The same could not be said of the medieval Arab philosophers, from al-Kindi to Averroes, who painstakingly subjected Aristotle to the demands of their belief in the one true God. And it was this “Arab Aristotle,” not so much the pagan thinker of classical Greece, who ultimately triumphed in the West. Once in place, much of this Aristotelian worldview—particularly its rigid, even doctrinaire, conception of the cosmos—would face centuries of critical study by Christian scholars, a reevaluation that ultimately would lead to something resembling modern science.

As it happened, a similar process had long since been under way in the lands of Islam.

Just as Avicenna and Averroes “corrected” Aristotelian metaphysics to make room for God, so from the eleventh century onward the Arab scientists—the successors to Baghdad’s House of Wisdom—assembled their own critical response to Greek astronomy and cosmology. The result was a theoretical and practical assault on the accepted architecture of the universe, codified by Ptolemy in the second century
A.D.
Gradually, the way was paved for that system’s complete overthrow, proposed by the Polish astronomer Nicolaus Copernicus in the mid-sixteenth century and completed by Isaac Newton 150 years later. This celestial revolution put the sun, rather than the earth, at the center of the universe and affirmed the predominant position of science in Western society.
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The transformation of man’s place in the heavens—from the center of attention to just one among many—required not only a profound psychological shift but also some high-powered scientific innovation. Here, too, the West got some vital help from the Arabs.

Specifically, the only “original” theorems in Copernicus’s monumental
De Revolutionibus
, published in 1543 as the scientist and churchman lay on his deathbed, have been traced directly to the earlier work of highly sophisticated Arab scientists unhappy with the teachings of the
Almagest
, Ptolemy’s great astronomical textbook. In the early years of Arab science, Abbasid scholars gently edited and revised this classic work. Supported by al-Mamun and some of the other early caliphs, these astronomers corrected Ptolemy’s calculation of the length of the solar month and greatly improved his measurement of the angle of the sun’s course around the earth, known as the ecliptic. Such initial changes, important but not fundamental to the underlying theory of the original work, were generally incorporated into updated Arabic translations of the Greek text.
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Other improvements to the
Almagest
were more significant, such as the introduction of the Arab trigonometric functions to replace or supplement the more cumbersome chords used in the Greek tradition. “I say, since the method of the moderns, which uses the sines at this point instead of the chords, is easier to use, as I will explain below, I wish to refer to it as well,” writes the astronomer Nasir al-Din Tusi in his
Redaction of the Almagest
in 1241.
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Such was the importance of this process that the medieval Latin translators got better results working with Arabic editions of the
Almagest
, rather than starting all over again with the unedited Greek original.

This gradualist approach was joined by more ambitious efforts to evaluate Ptolemy’s model of the universe on theoretical grounds. Here, the main sticking point was the
Almagest’s
readiness to violate, when necessary, one of the cardinal rules of natural philosophy, as taught by Aristotle and accepted by Ptolemy and his successors, including the Arabs: that celestial objects all moved in uniform circular motions, with the earth at their center. Ptolemy had already tried to account for the irregular movement of the celestial bodies with his notorious equant point, but he then shifted this theoretical axis of rotation away from the center of the earth—and thus from the center of the universe—in order to reflect centuries of observational data on how the planets actually moved when seen from the earth. By suggesting that some of these orbs effectively rotated around an axis that did not pass through the center of the universe, the
Almagest
introduced planetary motion that was neither perfect nor uniform.

This, said the early Arab critics, meant that Ptolemy’s account of planetary motions was “false,” giving rise to the theoretical literature known as
shukuk
, or “objections.”
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The oldest detailed critique dates to the mid-eleventh century, completed one hundred years before Hermann of Carinthia and Robert of Ketton struggled mightily in Spain to even understand the science of the
Almagest
well enough to translate it into Latin.