In a very famous story from the history of science, Galileo climbed to the top of the leaning bell tower at Pisa in order to refute Aristotle's teaching that bodies of different mass fall at different speeds.
This story (which may or may not be authentic) illustrates the image of Aristotle with which many of us grew up — that of a dogmatic ancient fool whose influence stunted scientific progress for centuries. Yet, in most ways, this image could not be further from the truth.
A student of Plato, who was a disciple of Socrates, Aristotle ranks, without any question, among the greatest universal geniuses the world has ever known. (His own pupil, Alexander the Great, was also a high achiever, although of a somewhat different kind.) His writings on poetry and theater, music, logic, rhetoric, politics and government, metaphysics and ethics are still fundamental to the study of those fields. And, while his work in biology, zoology, physics and other sciences has long been superseded, it played a vital role in creating those disciplines.
One of Aristotle's most influential contributions to human thought is his concept of the "unmoved mover."
As the name suggests, the unmoved mover moves other things, but is, itself, unmoved by anything else. It affects other things but isn't affected by other things. Think of an inconceivably long chain of dominos standing in line. In order to start them collapsing, somebody or something needs to tip the first domino over. All the rest follow.
Aristotle's understanding is that the unmoved mover is God, the ultimate cause or "mover" of all the motion, which (in his terms) meant all the change, in the universe. In the 12th book of his treatise on "Metaphysics," Aristotle describes the unmoved mover as being "simple" (that is, indivisible), unchangeable and perfectly beautiful. It endlessly contemplates the only thing in the universe worthy of its attention: itself.
Aristotle's prestige in the ancient and medieval periods was so enormous — and please recall that it was very far from undeserved — that Jewish, Christian and Muslim thinkers felt powerfully compelled to incorporate his view of God into their own.
For example, one of St. Thomas Aquinas's famous "five ways" of proving the existence of God (or, at least, of describing the divine nature) relies on Aristotle's concept of the unmoved mover.
This is hardly surprising. For roughly 20 centuries, Aristotle represented the best science and the most advanced thought available, and it would have been simply impossible for any serious thinker to ignore him. In fact, it was even difficult to contradict him: By the Middle Ages, as depicted in Umberto Eco's novel "The Name of the Rose" and in C.S. Lewis' scholarly study "The Discarded Image," the few precious writings remaining from "the Ancients" had taken on something of the aura of scripture. And no non-scriptural writer carried more authority than Aristotle.
A major problem for Muslim, Christian and Jewish thinkers, however, was that the God depicted in the Bible and the Quran is plainly personal, reacting to human sin and human faithfulness, intervening at some points in human history but not at others, revealing messages to prophets that are tailored to their specific times and circumstances. Yet the unmoved mover seems essentially impersonal. How were these two seemingly distinct conceptions of the divine to be reconciled, even blended?
It can be argued that they never really were. Not successfully. The unmoved mover, endlessly contemplating itself because it's the only thing in the universe worthy of its notice, seems unlikely to pay any attention to the sufferings of less worthy beings such as, say, humans. And if it truly affects all other things but cannot be affected, there appears little point in praying to it. One might as well pray to a rock. Finally, for Christians, is it even remotely conceivable that Aristotle's God "so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life" (John 3:16)?
Aristotle's concept of God and that taught in the Abrahamic revelations are like oil and water. They don't mix. As the early 20th century Anglo-American mathematician and philosopher Alfred North Whitehead once quipped with regard to this view of the divine (which he rejected), the God of the philosophers is, unfortunately, not available for religious use.