Hans Peter Broedel
This clerical embrace of Aristotle had a number of interesting consequences relevant to the development of medieval science. First, Aristotle believed that all knowledge originated in sense experience, which was a major departure from the epistemology (way of knowing) of St. Augustine and the earlier middle ages. High medieval churchmen certainly did not deny that direct revelation from God was possible, but insisted that it was unusual, and so the best way to understand God was to understand what we could perceive directly, that is, the natural world. As the theologian, Hugh of St. Victor put it in the twelfth century, “The whole of the sensible world is like a kind of book written by the finger of God… and each particular creature is somewhat like a figure, not invented by human decision, but instituted by the divine will to manifest the invisible things of God’s wisdom.”1 The work of natural philosophy , then, was to decode the book of nature, so to speak, in order to reveal the hidden hand of God. This led medieval scholars to study animals and plants, stars and planets, water, fire, and all manner of natural phenomenon. Further, although understanding God was the ultimate goal, his creation was assumed to follow rules that did not require His constant intervention, and so, like Aristotle, they described nature in what we would call “natural” terms. Miracles could, of course, still happen, but that was the provenance of theologians; natural philosophy dealt with nature, not with God directly.
In this way, medieval scholars were encouraged to explore the natural world, to build upon the work of their classical predecessors, but at the same time to acknowledge that the wonder of nature was a testament to the glory of God. Although they worked within an Aristotelian cosmos, and accepted as complete truth the great Philosopher’s (Aristotle’s) basic assumptions, they also recognized that their own work surpassed that of the ancients, both in its Christianity and in its capacity to build upon the achievements of the past. Bernard of Chartres, a twelfth-century philosopher and theologian, put it neatly when he observed that the scholars of his day were like “dwarves on the shoulders of giants and thus we see more and farther than they did.”2 This meant that when necessary they were even prepared to try to correct the great Philosopher’s mistakes.
Aristotle explained most things quite well, but his rules of motion were an exception. Aristotle dictated that inanimate objects move naturally to their proper sphere, but, otherwise, they only move if they are pushed by something else. This makes sense at first: if I want to move a piano, I’m going to have to push it, and once I stop, so will the piano. But what about an arrow? The motive force of the bow is removed when the arrow leaves the string, but the arrow clearly continues to move. Aristotle’s answer, like the rest of his physics, is extremely complicated, but he argues in effect