The great monotheistic religions have regarded Aristotle's philosophy with both appreciation and hostility. Christian, Islamic, and Jewish theologians generally approved of his well-ordered, teleological world in which final causes ordained that natural processes were directed toward the fulfillment of particular ends. Yet Aristotle rejected various important monotheistic tenants, including the belief that God is the ultimate cause of the existence of the world, the resurrection of the body, and the full immortality of the soul. As unqualified believers in these latter doctrines, Christians were particularly compelled to repudiate Aristotle. Theologians thus tended to reject or reinterpret what they took to be Aristotle's offensive opinions while generally accepting his larger natural philosophy.

Life and work

Aristotle was born in the town of Chalcidice in northern Greece in 384 B.C.E. His father was a physician to the King of Macedon. In 367, at the age of seventeen, Aristotle was sent to Athens to study at Plato's Academy, where he remained for twenty years, until Plato's death in 347. Since he was not chosen to replace Plato as the head of the Academy, Aristotle began a period of travel in Asia Minor, living for awhile in Assos (where he married a woman named Pythias) and then Lesbos until 342, when he accepted King Philip of Macedon's invitation to tutor his son, the future Alexander the Great, then fourteen years old. When Alexander succeeded his father as ruler in 335, Aristotle returned to Athens where he founded his famous school, the Lyceum. Thus began Aristotle's most productive period, which endured until 323, when news of the death of Alexander the Great provoked anti-Macedonian feelings in Athens. A false charge of impiety was made against Aristotle, who then fled Athens to Chalcis in Euboea, where he died in the following year, at the age of sixty-two.

It would be difficult to exaggerate the importance of Aristotle in the history of Western civilization. Not only were his numerous works a dominant factor in at least three civilizations (the Byzantine Empire, Islam, and the Latin West) using three different languages (Greek, Arabic, and Latin, respectively), but his works and ideas remained influential for approximately two thousand years. Aristotle's enormous influence derives not only from his overall brilliance, but also from the fact that he wrote treatises on a remarkable range of topics, which included metaphysics, logic, natural philosophy, biology, ethics, psychology, rhetoric, poetics, politics, and economics (or household management). He is regarded as the founder of two disciplines, logic and biology. The first book of Aristotle's Metaphysics is the first history of philosophy as well as the first history of science, while his Posterior Analytics is regarded as the first treatise on the philosophy, or methodology, of science. Finally, in six or seven treatises, Aristotle described the structure and operation of the world, thereby formulating a natural philosophy that served as the primary guide for natural philosophers from late antiquity to the seventeenth century in Western Europe, when it was displaced by a new world view associated with Nicolaus Copernicus, Galileo Galilei, Isaac Newton, and many others.

Aristotle reveals a scientific temperament in all his treatises, always emphasizing reason and reasoned argument. He was highly analytic, dividing and categorizing before arriving at important principles and generalizations. He always gives the impression of objectivity and detachment. In coping with any particular problem, Aristotle considered alternative solutions as carefully as possible before resolving the problem.

Aristotle and the divine

Aristotle's views about religion and divinity play a role in his overall conception of the cosmos and its workings. In Book Eight of his Physics, he describes what he calls the "Unmoved Mover" or "Prime Mover," which is the ultimate source, or cause, of motion in the universe, but is itself unmoved. For Aristotle this is God, who dwells at the circumference of the universe and causes motion by being loved. The closer to the Unmoved Mover a body is, the more quickly it moves. Although the Unmoved Mover is God, it did not create the world, which Aristotle regarded as uncreated and eternal. As the prime mover, God enjoys the best kind of life, being completely unaware of anything external to itself and, being the most worthy object of thought, thinks only of itself.

Aristotle's God was clearly not a divinity to be worshipped. Apart from serving as the ultimate source of motion, God, ignorant of the world's existence, could play no meaningful role in Aristotle's natural philosophy. Nevertheless, Aristotle seems to have had a strong sense of the divine, which manifested itself in a sense of wonderment and reverence for the universe.

Aristotle's sense of God was unacceptable to Christians, Muslims, and Jews. Although Plato's concept of a God who created from pre-existent matter was also unacceptable, it was far more palatable to monotheists than was Aristotle's Unmoved Mover, who did not create the world. Indeed, it could not have created the world because, argued Aristotle, the world is eternal, without beginning or end. Aristotle insisted that the material world could not have come into being from another material entity, say B. For if it did, one would have to ask from whence did B come? Such an argument would lead to the absurdity of an infinite regression, prompting Aristotle to argue that the world has always existed, an interpretation that posed further problems for Muslims and Christians. Consistent with his assumption of an eternal world, Aristotle regarded creation from nothing as impossible.

Aristotle's concept of nature was fully compatible with those of the major religions. Indeed he provided basic interpretations that were widely adopted. Aristotle distinguished four operative causes in nature:

1. the material cause, or that from which something is composed;
2. the efficient cause, or the agent that made something come into being;
3. the formal cause, or the characteristics that make it what it is; and
4. the final cause, or the purpose for which something exists.

It is the last cause that makes Aristotle's system teleological. Although he did not believe that conscious purposes existed in nature, he was convinced that processes in nature aim toward an end or goal and that "nature does nothing in vain." It is therefore appropriate to characterize Aristotle's natural philosophy and science as teleological, a view of nature's operations that fits nicely into the Christian conception of God's creation.

The manner in which Aristotle argued and rendered judgments provoked Christian theologians in the Middle Ages. On a number of issues, Aristotle produced arguments about the physical world that led him to conclude the impossibility of certain phenomena. For example, in the fourth book of Physics, Aristotle argued that the existence of a vacuum is impossible inside or outside of our world. Space is always full of matter, which resists the motion of bodies. In the absence of matter in a vacuum, resistance to motion of any kind would be impossible. Without resistance to its motion, a body would move instantaneously, which is impossible.

In the first book of his treatise On the Heavens, Aristotle showed the impossibility of the existence of other worlds. Our world, Aristotle argued, contains all the matter there is, with no surplus left to form one or more other worlds, from which he concludes that "there is not now a plurality of worlds, nor has there been, nor could there be."

Aristotle also argued that without exception all accidental properties—that is, properties that are not essential for the existence of a thing—such as colors, the height of an individual, the size of one's foot, and so on, had of necessity to inhere in the substances of which they were the property. It was impossible that an accidental property exist independently of its subject.

In these, and similar instances, Christians were alarmed at the implications of Aristotle's arguments, for it seemed to place limits on God's absolute power to do whatever God pleased, short of a logical contradiction. Did those who accepted Aristotle's natural philosophy and metaphysics believe that God could not supernaturally create a vacuum just because Aristotle had argued that it was naturally impossible? Did they believe that God could not create other worlds if God wished, simply because Aristotle had argued that other worlds were impossible? And did they regard Aristotle's argument as unqualifiedly true when he declared it impossible that accidents of a substance could exist independently of that substance? The latter claim violated the doctrine of the Eucharist, namely that when God transforms the bread and wine of the Mass into the body and blood of Christ, the accidents of the bread and wine continue to exist without inhering in any substances. The uneasiness with limitations on God's absolute power led theologians in the thirteenth century to place restrictions on Aristotle's natural philosophy. Despite the attempt to circumscribe Aristotle's ideas, the effort did not in any way dampen the enthusiasm with which his works were received in the Latin West, where, during the fourteenth to early seventeenth centuries, they functioned as the curriculum in the arts faculties of virtually all of the sixty to seventy universities that had come into existence by that time.

Conclusion

Why did the works of Aristotle become so popular in the West despite the many ideas he had proposed that were offensive to Christians and Christianity? The answer is quite simple: His collected works ranged over many themes and subjects and were therefore too valuable to ignore. Moreover, no rival body of literature existed that could pose even a remote challenge to it. By the early seventeenth century, however, numerous new currents of thought came together to subvert Aristotle's natural philosophy, which was largely overwhelmed and by-passed by the end of the seventeenth century.

See also GALILEO GALILEI; GOD; ISLAM; METAPHYSICS; NEWTON, ISAAC; PLATO; TELEOLOGY

EDWARD GRANT