The Friar and the Cipher (11 page)

CHAPTER TEN

Theology Becomes a Science:
The Logic of Thomas Aquinas

•   •   •

AQUINAS HAD LEFT PARIS IN 1259
(giving up his chair to the next Dominican) and went to the priory at Naples, where he had been originally inducted into the order. As the first Italian to earn a chair in theology in Paris (just as Albert had been the first German), he was, according to an early biographer, “the splendor of the Roman province.” He was made a preacher general, which gave him a voice in making policy, and was also allowed a good deal of time to study and work. Almost from the moment he arrived, he was assigned a personal secretary, Reginald of Piperno. Reginald would spend the rest of his life following his master around from place to place, taking notes or dictation and transcribing Aquinas's notoriously difficult-to-read handwriting.

Since the time of Saint Dominic, the Friars Preachers had sent a representative to the pope, a liaison between the papacy and the order, a position that had evolved into a high-level advisory post on matters of theology. Every pope was required to field questions from all over Europe on Church doctrine, and whoever answered those questions in effect set religious policy. In 1261, the order sent Aquinas to the papal court at Orvieto to become the pope's theologian.

Intellectually, there could not have been a better man for the job. Unlike his contemporaries who merely read philosophy and applied it—most in something of a slapdash manner—Aquinas
was
a philosopher, the greatest mind in the Church since Augustine.

When he assumed his position at the pope's side, theological policy was very much up for grabs. On one side was Bonaventura, the last great Augustinian philosopher, who rejected Aristotle's logic and fought to retain the mystical interpretations that had guided Church doctrine for eight centuries. Although opposition to Aristotle was centered among the Franciscans, fear of the Philosopher was widespread, even among Dominicans. At the other extreme were those who unconditionally embraced Aristotle, or at least the Aristotle of Averroës. Proponents of this view were centered among the arts masters at Paris who were beginning to form themselves into a cohesive movement. These scholars believed not only that reason just might hold primacy over faith, but, even more threatening, that scripture needed a complete overhaul or at least a reinterpretation to bring it into line with the new science.

Aquinas could now use his position to attempt to negotiate a path through these two seemingly irreconcilable arguments. It was his genius that he understood—as probably did Bacon as well—that the war over theory was already over. It was no longer a question of whether Bonaventura and the Augustinians could hold back the Aristotelian tide, but only in what manner Aristotle was going to be incorporated into dogma.

During his tenure at Orvieto, Aquinas set himself to obtaining the fullest and most comprehensive translations of Aristotle possible. Not satisfied with the Latin versions rendered in Spain and Sicily, he began to utilize more recent translations, these from William of Moerbeke, a Dominican who would later become bishop of Corinth. It is likely that some of William's later translations were the direct result of entreaties by Aquinas perhaps even at the behest of the pope, but, in any event, Aquinas gobbled them up as quickly as William could turn them out.

From there, Aquinas began a line-by-line analysis of Aristotle's work, an undertaking not attempted since Averroës. (Albert had merely translated and explained, sometimes creatively, but had not tried to interpret.) To this Aquinas added an equally scrupulous analysis of the Arabic commentaries. This work would occupy him for the rest of his life and, when he was done, he had remade not only Aristotle but the Christian faith as well.

In one of the most brilliant leaps that any theologian would ever attempt, Aquinas decided that if Christian revelation could not be made to conform to Aristotelian logic, then somehow Aristotelian logic would have to be made to conform to Christian revelation. He met the challenge of scientific inquiry by making theology a theoretical science in itself. He produced scholastic, Aristotelian proofs for every key scriptural assertion, everything from the existence of God to the primacy of revelation, to the pseudo-Christianity of Aristotle. Although the Church did not yet know or appreciate it, Thomas Aquinas almost single-handedly gave Catholicism the tools with which to repel the onrush of empirical science. Because of him, for the next three centuries, the Church would maintain its supremacy as the ultimate authority over matters not only of heaven but of earth as well. So far ahead of any other theological thinker was Aquinas that his time is often referred to as “The Age of Scholasticism,” almost as if the previous seven hundred years had not existed.

Aquinas was as prolific as he was brilliant. He produced more than sixty works, thousands upon thousands of pages. In one work alone, his famed
Summa Theologica
—unfinished when he died—Thomas posited 512 questions with 2,669 articles, and then produced proofs to dispense with more than 10,000 objections.

His organization of a problem and use of logic were dazzling—Aristotle could have asked no greater practitioner of his method. Aquinas posed a question, postulated the range of potential arguments, then systematically and painstakingly eliminated every invalid conclusion, false hypothesis, logical inconsistency, or misapplied premise until he had reduced the possibilities to just one—that which he had sought to prove in the first place. It was as if, in the densest of forests, reaching one fork in the trail after another, although he had a map (indeed, he had drawn it), he deliberately proceeded down every false path until each was exhausted, all to prove that only one correct way through the thicket existed. When trying to follow someone engaged in such an exercise, it is best not to fall too far behind, lest one risk becoming hopelessly lost. The temptation, therefore, to simply agree to certain premises in the rush to keep up, to take the guide's word for it, can be powerful indeed.

Aquinas's favorite technique for incorporating Aristotle into Catholicism was to prove that the arguments of the Philosopher and the tenets of faith were not inconsistent after all. He dealt with these issues throughout his career. A wonderful example of his method is in an
opusculum
(short work) called
De Aeternitate Mundi (On the Eternity of the World
).

Aristotle had very clearly stated in
On the Heavens
that “the universe as a whole neither came into being nor can it be destroyed . . . On the contrary, it is unique and everlasting. It has neither a beginning nor an end . . . and it also contains within itself time without end.” Finding a way to make
that
conform to Christian dogma was going to be some trick. Both Bacon and Albert had tried and failed.

Aquinas began, “Let us assume, in accordance with the Catholic faith, that the world had a beginning in time. The question still arises whether the world could have always existed . . .” Even Aquinas knew better than to try to prove logically that two contrary statements were both true, so he came at the problem from a different angle. Christian dogma said that the world was created at a finite point in time by an act of will by God, so this statement
must
be true, and therefore Aristotle's contention that the world was eternal had to be false. But what if it was false by coincidence rather than philosophic error? In other words, what if God could have made the world eternal had He chosen, but instead
chose
to create it specifically in the manner delineated by Christian faith? That would preserve the Aristotelian structure while at the same time reaffirming revelation.

And, in a clear and cogent, step-by-step process, this is precisely what Aquinas proceeded to prove.

First, he stipulated that everyone, Christians and philosophers alike, agreed that something not made by God could not have always existed. “Everything that in any way exists, cannot exist unless it is caused by him who supremely and most truly has existence,” he observed. “However, someone may hold that there has always existed something that, nevertheless, has been wholly caused by God, and thus we ought to determine whether this position is tenable.”

If, Aquinas went on, it is impossible for something caused by God to have always existed, it is either because God lacked the power to cause it—obviously untrue—or that something that has always existed for some reason could not be made, even though God
could
have made it. If, in turn, something God had the power to make
couldn't
be made, it was only because either it lacked the potential to be made—passive potentiality, as Aquinas put it—as steel cannot be made without the presence of iron ore or a two-by-four cannot be made without a pine tree, or because it was contradictory.

To demonstrate that the first alternative was false, that something could be made even without “passive potentiality,” Aquinas used the example of angels. Since God most certainly made angels even though “no passive potentiality precedes its being,” then it followed that “a passive potentiality need not precede in time whatever God may make.”

That leaves the second case, which is that God cannot make that which is self-contradictory, “just as an affirmation and a denial cannot be made simultaneously true,” or, as Thomist scholar Ralph McInerny phrased it, something cannot at the same time be “p” and “not p.” (It is interesting that neither Aquinas nor those who study him ever accept the possibility that the laws of logic do not apply to God at all, and thus the entire structure upon which scholasticism is built is unstable.) Aquinas granted that, although some great men have “piously maintained” that God can cause contradictory events, he believed that they were mistaken. In either case, Aquinas concluded that there was no contradiction between being made by God and having always existed. “It would clearly be derogatory to divine omnipotence . . . to say that we creatures can conceive of something that God is unable to make.”

Aquinas concluded
De Aeternitate Mundi
having proved the perilous, antiscriptural conclusion that God may well have made something that has always existed. At first blush, this is exactly what the Augustinians feared, a demonstration that Aristotle might be right and the Bible wrong. This, of course, was not at all what Aquinas had in mind, as Dr. McInerny points out. “While [Aquinas] firmly accepts as revealed truth, as a truth of faith, that the duration of the world had a beginning, that time and the world began . . . God might have done what he in fact did not do, namely, create an eternal world.” McInerny then cites the passage in
Summa Theologica
that demonstrates the genius of this conclusion. “The arguments Aristotle puts forth are not demonstrative in the strict sense, but only broadly speaking, since what they do is disprove those arguments of the ancients which attempted to show that the world has come to be in one of the ways in which this is truly impossible.”

In other words, the man who stated that the universe “has neither a beginning nor an end” was actually supportive of Christian doctrine all the time.

WHAT AQUINAS DID HERE AND ELSEWHERE
was what attorneys attempt to achieve in legal briefs—present an interpretation that both fits the facts and leads to the conclusion favorable to the client. While it may have been impossible to prove that Aquinas's arguments were wrong, it was equally impossible to prove that they were right. Not once in the thousands of pages that he produced did a conclusion of Aquinas's ever result in anything other than that which he had originally sought to prove.

Aquinas intended logical construct to be a science in itself, to remove the necessity—or even the possibility—of empirical verification. There were some significant practical consequences. Because Aquinas made no distinction between method and conclusion, many of Aristotle's scientific conclusions that were just plain wrong, such as the geocentric universe and the division of matter into earth, air, fire, and water, became cornerstones of natural science within the Christian religion. Since it was often hard to define where permissible scientific inquiry ended and the truth of faith began, all of these dubious truths were now off-limits and thus inviolable.

Although
Summa Theologica
is his most famous work, another treatise,
Summa Contra Gentiles
(
Summary of the Arguments Against the Disbelievers
) had a far greater impact during his lifetime.

Aquinas began the work in Paris in the late 1250s but did not complete it until 1264. It was believed to have been written, at least in part, in response to a request by a former master general of the Dominican order living in Barcelona who, “ardently desiring the conversion of infidels,” asked Aquinas “to write a work . . . that would both take away the thick atmosphere of darkness [for infidels] and unfold the doctrine of true light to those willing to believe.”

Summa Contra Gentiles
was divided into four parts, the first three consisting of that which can be known by reason and the fourth devoted to that which can be known only by faith. It did not make much of a ripple in Spain—it is unclear whether it precipitated a single conversion—but it caused an immediate sensation in centers of learning across the rest of Europe. It was perhaps the most lucid, organized treatment of Church philosophy since Augustine, and the name of Thomas Aquinas was on everyone's lips. It is inevitable that word of this great achievement would have penetrated even the most cloistered Franciscan monasteries in Paris.

In
Summa Contra Gentiles
, all of Thomas's vast powers were brought to bear—the patient enunciation, relentless logic, and unblemished piety—all to prove that which could be proved and to persuade to accept as faith that which could not. But all of Aquinas's flaws were on display as well, particularly the willingness to manipulate premise or conclusion to fit a predetermined belief.