20.
soul and discusses perception and the senses. Aristotle’s metaphysics, or “first philosophy,” or “theology,”
as it was sometimes called, is embodied in his work titled Metaphysics. In this basic work, Aristotle analyzes the nature of immaterial being wholly divorced from matter. Despite its problematic nature, Christian theologians found the Metaphysics an invaluable resource for confronting difficult problems about God’s nature and existence.
Aristotle’s Theology
Aristotle’s metaphysics and natural philosophy had a profound, and often disquieting, effect on the theologians and religious guardians of the monotheistic religions of Christianity, Islam, and Judaism.
Various elements in Aristotle’s philosophy were relevant to theology, most notably his conviction that the world is eternal: that it had no beginning and would never have an end. Aristotle could find no convincing argument for supposing that our world could have come into being naturally from any prior state of material existence. For if the world came from a previously existing material thing, say B, we would then have to inquire from whence did B come, and so on through an infinite regression, since it was assumed that the world could not have come from nothing. To avoid this dilemma, Aristotle concluded that the world had no beginning and, therefore, that it could have no end, for if it could end, it could, necessarily, have had a beginning.
Despite his conviction that the world was uncreated, Aristotle did believe in a divine spirit, or God. But the attributes he assigned to his God, whom he called an “Unmoved Mover,” would have been strange, and perhaps repugnant, to anyone raised in one of the three traditional monotheistic religions. Obviously, Aristotle’s God was not the creator of our world, since it is uncreated. Indeed, he is not even aware of the world’s existence and, therefore, does not, and could not, concern himself with anything in our world. Such a deity could not, therefore, be an object of worship. The only activity fit for such a God is pure thought. But the only thoughts worthy of his exalted status are thoughts about himself. Totally remote from the universe, Aristotle’s God thinks only about himself.
Despite his total isolation from the world, the God of Aristotle unknowingly exerted a profound influence on it. He was its “Unmoved Mover,” causing the orbs and the heavens to move around with eternal circular motions. The celestial orbs move around eternally because of their love for the Unmoved Mover. By virtue of these incessant motions, the celestial orbs cause all other motions in the world. Thus was Aristotle’s Unmoved Mover, or God, the final cause of all cosmic motions.
Aristotle’s view of the human soul also proved problematic. He regarded the soul as a principle of life that was inseparable from its body. Aristotle distinguished three levels of soul: (1) the nutritive, or vegetative, soul, which is found in both plants and animals and is solely concerned with the nutrition essential for the sustenance of the organism’s life; (2) the sensitive soul, which is possessed only by animals and oversees motion, desire, and sense perception; and (3) the rational soul, which is found only in humans and subsumes the two lower levels of soul to form a single, unified soul in each human being. Each human soul contains an active and a passive intellect. Our thoughts are formed from images abstracted by the active intellect and implanted in the passive intellect as concepts. Except for the active intellect, which is immortal, the soul perishes with the body. Whether Aristotle regarded an individual’s active intellect as personally immortal or whether he thought it loses its individuality when it rejoins the universal active intellect is unclear. Those who wished to “save” Aristotle and reconcile his view with the Christian conception of the soul opted for the first alternative, even though such an interpretation involved an elastic view of Christian doctrine.
Aristotle’s strong sense of what was possible and impossible in natural philosophy posed serious problems for his Christian, Muslim, and Jewish followers. On a number of vital themes, he presented demonstrations
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to show that nature was necessarily constrained to operate in one particular way rather than another way.
The question confronting Aristotle’s followers, then, was whether God could have created our world to operate in ways that Aristotle regarded as impossible.
Later Antiquity, Byzantium, and Islam
Such difficulties were of little concern to the earliest commentators, who were pagans like Aristotle himself. Not until members of the great monotheistic religions began to comment on the works of Aristotle did problems arise. Although the names of the earliest commentators are unknown, commentaries on Aristotle’s works were probably written in the Hellenistic period (323–30 B.C.), shortly after his death, and they continued on through the duration of the Roman Empire (30 B.C.–A.D. 476). The historical emergence of the Aristotelian commentary tradition took place in the Greek-speaking area that would become the Byzantine Empire in the eastern Mediterranean world. Here, beginning in the third cen tury A.D., a group of commentators writing in Greek began the historical development of Aristotelianism (the tradition of commenting on the works of Aristotle). The most prominent of these were Alexander of Aphrodisias (fl.
second or third century), Themistius (317–c. 388), Simplicius (d. 540), and, especially, the Christian Neoplatonic author John Philoponus (d. c. 570), who rejected many of Aristotle’s basic concepts about the nature of the world. After the translation of some of their works into Arabic, these Greek commentators exercised a significant influence on Islam.
Because of religious hostility to Aristotle’s natural philosophy, the number of Aristotelian commentators in Islam was not large. The most important of them—al-Kindi (800–70), al-Farabi (873–950), Avicenna (Ibn Sina [980–1037]), and Averroës (Ibn Rushd [1126–98])— were translated into Latin and exerted a major influence in the European Middle Ages—in some instances, playing a greater role in Christendom than in Islam. Three of the most important charges against Aristotle’s natural philosophy were: (1) his advocacy of the eternity of the world; (2) the conviction that his natural philosophy was hostile to the basic Muslim belief in the resurrection of the body; and (3) his concept of secondary causation. In Islamic thought, the term “philosopher” (faylasuf) was often reserved for those who assumed, with Aristotle, that natural things were capable of causing effects, as when a magnet attracts iron and causes it to move or when a horse pulls a wagon and is seen as the direct cause of the wagon’s motion. On this approach, God was not viewed as the immediate cause of every effect. Philosophers believed, with Aristotle, that natural objects could cause effects in other natural objects because things had natures that enabled them to act on other things and to be acted upon. By contrast, most Muslim theologians believed, on the basis of the Koran, that God caused everything directly and immediately and that natural things were incapable of acting directly on other natural things. Although secondary causation was usually assumed in scientific research, most Muslim theologians opposed it.
The European Middle Ages
Aristotle’s ideas were destined to play a monumental role in western Europe. In the twelfth and thirteenth centuries, his works, along with much of Islamic science and natural philosophy, were translated from Arabic into Latin. The Arabic commentaries on Aristotle spoke favorably of the philosopher and, once translated, were often used in Europe as guides to his thought. Indeed, Averroës, who was probably the greatest of all Aristotelian commentators, was known to all simply as “the Commentator.”
Until the thirteenth century, Aristotelian commentators were a disparate group scattered in time and place.
All of this changed, however, with the emergence of universities around 1200. Aristotle’s thought achieved
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a widespread prominence as his logic, natural philosophy, and metaphysics became the basis of the curriculum leading to the baccalaureate and master of arts degrees. As a result, universities in western Europe—and by 1500 there were approximately sixty of them in Europe, extending as far east as Poland—
became the institutional base for Aristotelianism. A relatively large class of professional teachers developed who were specialists in Aristotelian thought, and a much larger class of non-teaching scholars emerged who had studied Aristotelian natural philosophy and metaphysics in depth. Nothing like this had ever been seen before. For the first time in history, natural philosophy, the exact sciences (primarily geometry, arithmetic, astronomy, and optics), and medicine were permanently rooted in an institution, the university, that has endured for approximately eight hundred years and has been established worldwide.
By the end of the thirteenth century, the method of teaching both theology and Aristotle’s natural philosophy, which significantly influenced theology, was to proceed by way of a series of questions.
Indeed, the very titles of many of the treatises indicate their pedagogical method. For example, in his Questions on Aristotle’s Book on the Heavens, John Buridan (c. 1295–c. 1358), perhaps the greatest arts master of the Middle Ages, proposed and responded to the following questions: “whether there are several worlds”; “whether the sky is always moved regularly”; “whether the stars are self-moved or moved by the motion of their spheres”; “whether the earth always rests in the middle [or center] of the world”; and many others about the terrestrial and celestial regions. Similar questions were posed in various treatises on Aristotle’s other works. Peter Lombard (c. 1100–c. 1160), for example, employed the questions format in his Sentences. Composed in the 1140s, Sentences was the great theological textbook of the late Middle Ages, an essential work on which all bachelors in theology lectured and commented. Many of the questions fused natural philosophy and theology, utilizing natural philosophy to resolve theological issues, especially in the second book, which considered the Creation. They covered such matters as “whether God could make a better universe”; “whether the empyrean heaven is luminous”; “whether light is a real form”; “whether the heaven is the cause of these inferior things”; “whether every spiritual substance is in a place”; “whether God could make something new”; and “whether God could make an actual infinite.”
Logic, natural philosophy, and the exact sciences, along with the scholastic methods for treating these subjects, became permanent features of medieval universities. But the entry of natural philosophy into the curriculum of the University of Paris, the premier university of western Europe during the Middle Ages, differed markedly from its entry into other contemporary universities, such as Oxford and Bologna. While the exact sciences and medicine encountered little opposition, Aristotelian natural philosophy met a different fate. Christianity, during its first six centuries, had adjusted fairly easily to pagan Greek learning and had adopted the attitude that Greek philosophy and natural philosophy should be used as “handmaidens to theology” (that is, they should be studied for the light they shed on Scripture and theological problems and for any insights they might offer for a better understanding of God’s Creation). Nevertheless, some influential theologians in Paris, specifically those at the university, were deeply concerned about the potential dangers that Aristotelian natural philosophy posed for the faith. During the first half of the thirteenth century, the Parisian authorities first banned the works of Aristotle, decreeing in 1210 and 1215 that they were not to be read in public or private. Subsequently, in 1231, they sought to expurgate his works, an intention that was apparently never carried out. By 1255, Aristotle’s works had been adopted as the official curriculum at the University of Paris. Efforts to deny entry of Aristotelian natural philosophy into the University of Paris failed utterly. The reason is obvious: For Christians, the value of Aristotle’s works, and the commentaries thereon, far outweighed any potential danger they might pose.
During the second half of the thirteenth century, a number of conservative theologians, who were still concerned about the impact of Aristotelian thought, changed their means of attack. Rather than attempt to ban or expurgate Aristotle’s works, they now sought to identify and condemn specific ideas that they
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believed were dangerous to the faith. When it became apparent that repeated warnings about the perils of secular philosophy were to no avail, the traditional theologians appealed to the bishop of Paris, Etienne Tempier (d. 1279). In 1270, Tempier intervened and condemned 13 articles that were derived from the teachings of Aristotle or were upheld by his great commentator, Averroës. In 1272, the masters of arts at the University of Paris instituted an oath that compelled them to avoid consideration of theological questions. If, for any reason, an arts master found himself unable to avoid a theological issue, he was further sworn to resolve it in favor of the faith. The intensity of the controversy was underscored by Giles of Rome’s (c.
1243–1316) Errors of the Philosophers, written sometime between 1270 and 1274, in which Giles compiled a list of errors drawn from the works of the non-Christian philosophers Aristotle, Averroës, Avicenna, al-Ghazali (1058–1111), al-Kindi, and Moses Maimonides (1135–1204). When these counter-moves failed to resolve the turmoil or abate the controversy, a concerned Pope John XXI instructed the bishop of Paris, still Etienne Tempier, to initiate an investigation. Within three weeks, in March 1277, Tempier, acting on the advice of his theological advisers, issued a massive condemnation of 219 articles. Excommunication was the penalty for holding or defending any one of them. Although the condemned articles were drawn up in haste without apparent order and with little concern for consistency or repetition, many, if not most, of the 219 articles reflected issues that were directly associated with Aristotle’s natural philosophy and, hence, form part of the history of the reception of Aristotelian learning. Some 27 of the articles—more than 10 percent—condemned the eternity of the world in a variety of guises. Numerous articles were condemned because they set limits on God’s absolute power to do things that were deemed impossible in Aristotle’s natural philosophy.
Scattered through the works of Aristotle were propositions and conclusions demonstrating the natural impossibility of certain phenomena. For example, Aristotle had shown that it was impossible for a vacuum to occur naturally inside or outside the world, and he had also demonstrated the impossibility that other worlds might exist naturally beyond ours. Theologians came to view these Aristotelian claims of natural impossibility as restrictions on God’s absolute power to do as he pleased. Just because Aristotle had declared it impossible, why should an omnipotent God not be able to produce a vacuum inside or outside the world, if he chose to do so? Why could he not create other worlds, if he wished to do so? Why should he not be able to produce an accident without a subject? And why should he not be able to produce new things in the world that he had created long ago? A condemned article was issued for each of these restrictions on God’s power. As if to reinforce all of the specific articles, the bishop of Paris and his colleagues included a separate article (147) that condemned the general opinion that God could not do what was judged impossible in natural philosophy.
By appeal to the concept of God’s absolute power, medieval natural philosophers introduced subtle and imaginative questions that often generated novel responses. By conceding that God could create other worlds, they inquired about the nature of those worlds. By assuming that God could, if he wished, create vacuums anywhere in the universe, they were stimulated to pose questions about the behavior of bodies in such hypothetical vacuums. They asked, for example, whether bodies would move with finite or infinite speeds in such empty spaces. They posed similar questions about a variety of imaginary, hypothetical physical situations. Although these speculative questions and their responses did not cause the overthrow of the Aristotelian worldview, they did challenge some of its fundamental principles and assumptions. They made many aware that things might be quite otherwise than were dreamt of in Aristotle’s philosophy.
Despite the adverse theological reaction to some of Aristotle’s ideas and attitudes during the thirteenth century, it would be a serious error to suppose that medieval theologians in general opposed Aristotelian natural philosophy. If the majority of theologians had chosen to oppose Aristotelian learning as dangerous to the faith, it could not have become the focus of studies in the universities. But theologians had no
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compelling reason to oppose it. Western Christianity had a long-standing tradition of using pagan thought for its own benefit. As supporters of that tradition, medieval theologians treated the new Greco-Arabic learning in the same manner—as a welcome addition that would enhance their understanding of Scripture.
Indeed, we can justifiably characterize medieval theologians as theologian-natural philosophers, since almost all of them were thoroughly trained in natural philosophy, which was a virtual prerequisite for students entering the higher faculty of theology. So enthusiastically did these theologian-natural philosophers incorporate natural philosophy into their theological treatises that the Church had to admonish them, from time to time, to refrain from frivolously employing it in the resolution of theological questions.
Some of the most significant contributors to science, mathematics, and natural philosophy came from the ranks of theologians, as is obvious from the illustrious names of Albertus Magnus (1193–1280), Robert Grosseteste (c. 1168–1253), John Pecham (d. 1292), Theodoric of Freiberg (d. c. 1310), Thomas Bradwardine (c. 1290–1349), Nicole Oresme (c. 1320–82), and Henry of Langenstein (fl. 1385–93). The positive attitude of medieval theologians toward Aristotelian natural philosophy, and their belief that it was a useful tool for the elucidation of theology, must be viewed as the end product of a long-standing attitude that was developed and nurtured during the first four or five centuries of Christianity and maintained thereafter in the Latin West.
The Early-Modern Period
Because Aristotle’s works formed the basis of the medieval university curriculum, Aristotelianism emerged as the primary, and virtually unchallenged, intellectual system of western Europe during the thirteenth to fifteenth centuries. Not only did it provide the mechanisms of explanation for natural phenomena, it also served as a gigantic filter through which the world was viewed. Whatever opposition theologians may once have offered to it, by the thirteenth century that opposition had long ceased. Aristotelian physics and cosmology were triumphant and dominant. By the sixteenth and seventeenth centuries, however, rival natural philosophies had materialized following a wave of translations of new Greek philosophical texts previously unknown in the West. Opposition to Aristotelianism now became widespread. As a direct consequence of the new science that was emerging in the first half of the seventeenth century, the positive medieval attitude toward science and natural philosophy that prevailed in the late Middle Ages underwent significant change. In the aftermath of the Council of Trent (1545–63), the Roman Catholic Church came to link the defense of the faith with a literal interpretation of those biblical passages that clearly placed an immobile earth at the center of the cosmos. By this move, it aligned itself with the traditional Aristotelian-Ptolemaic geocentric universe in opposition to the Copernican heliocentric system. In 1633, the Church condemned Galileo (1564– 1642) for upholding the truth of the Copernican heliocentric planetary theory.
By condemning Galileo, the Church and its theologians came to be viewed as obscurantists who were hostile to science and natural philosophy. Instead of confining that opinion to Aristotelian scholasticism of the seventeenth century, when Aristotelian natural philosophy was under assault and nearing the end of its dominance in European intellectual life, the critics of Aristotle and Aristotelianism indiscriminately included the late Middle Ages in that judgment and viewed it as an equally unenlightened period.
In this way, medieval attitudes toward science and natural philosophy have been seriously distorted. The aftermath of Galileo’s condemnation produced hostility and contempt toward the late Middle Ages. Not only was the attitude of theologians toward natural philosophy misrepresented, but the positive role that Aristotle and Aristotelian natural philosophers played in the history of science was ignored, as was the legacy they bequeathed to the seventeenth century. More than anyone else in the history of Western thought, it was Aristotle who molded and shaped the scientific temperament. He was the model for the
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Middle Ages. Gradually, medieval scholars reshaped and supplemented Aristotle’s methods and insights by their own genius and fashioned a more sophisticated body of natural philosophy, which they passed on to the scientists and natural philosophers of the seventeenth century. This legacy included a variety of methodological approaches to nature that had been applied to a large body of important questions and problems about matter, motion, and vacuums. These questions were taken up by nonscholastic natural philosophers in the seventeenth century. Initially, the scientific revolution involved the formulation of successful responses to old questions that had been posed during the Middle Ages.
Embedded in the vast medieval Aristotelian commentary literature was a precious gift to early-modern science: an extensive and sophisticated body of terms that formed the basis of scientific discourse. Terms such as “potential,” “actual,” “substance,” “property,” “accident,” “cause,” “analogy,” “matter,” “form,”
“essence,” “genus,” “species,” “relation,” “quantity,” “quality,” “place,” “vacuum,” and “infinite” formed a significant component of scholastic natural philosophy. The language of medieval natural philosophy, however, did not consist solely of translated Aristotelian terms. New concepts, terms, and definitions were added, most notably in the domains of change and motion, in which new definitions were fashioned for concepts like uniform motion, uniformly accelerated motion, and instantaneous motion.
The universities of the Middle Ages, in which natural philosophy and science were largely conducted, also conveyed a remarkable tradition of relatively free, rational inquiry. The medieval philosophical tradition was fashioned in the faculties of arts of medieval universities. Natural philosophy was their domain, and, almost from the outset, masters of arts struggled to establish as much academic freedom as possible. They sought to preserve and expand the study of philosophy. Arts masters regarded themselves as the guardians of natural philosophy, and they strove mightily for the right to apply reason to all problems concerning the physical world. By virtue of their independent status as a faculty with numerous rights and privileges, they achieved a surprising degree of freedom. During the Middle Ages, natural philosophy remained what Aristotle had made it: an essentially secular and rational enterprise. It remained so only because the arts faculty, whose members were the teachers and guardians of natural philosophy, struggled to preserve it. In the process, they transformed natural philosophy into an independent discipline that had as its objective the rational investigation of all problems relevant to the physical world. However, the success of the arts masters was dependent on the theological faculties, which were sympathetic to the development of natural philosophy. Despite the problems of the thirteenth century, medieval theologians were as eager to pursue that discipline as were the arts masters. If that had not been so, medieval natural philosophy would never have attained the heights it reached, nor would it have been so extensively employed. For not only was natural philosophy imported into theology, especially into theological commentaries on the Sentences of Peter Lombard, the textbook of the theological schools for five centuries, but it was also integrated into medicine, both in the standard textbooks of physicians such as Galen (129–c. 210), Avicenna, and Averroës and in the numerous medical commentaries by physicians who were thoroughly acquainted with Aristotle’s natural philosophy and recognized its importance for medicine. Even music theorists occasionally found it convenient to introduce concepts from natural philosophy to elucidate musical themes and ideas.
Finally, the seventeenth century also inherited from the late Middle Ages the profound sense that all of these activities were legitimate and important; that discovering the way the world operated was a laudable undertaking. Without the crucial centuries of medieval Aristotelianism to serve as a foundation, the scientific revolution of the seventeenth century would have been long delayed or might still lie in the future.
See also Islam; Medieval Science and Religion; Natural History;
Plurality of Worlds and Extraterrestrial Life; Thomas Aquinas and Thomism; Varieties of Providentialism
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