Redefining Reality - The Intellectual Implications of Modern Science

All the earthly elements have a natural place, and their natural
state of motion is in a straight line to that place, where they then
remain at rest. Motion is caused by an internal drive within the
object based on its nature.
The Greeks believed that all the objects close to Earth are made up
of the four elements, but extraterrestrial objects—the Sun, Moon,
Because aether is a more perfect element, objects made of it take
on a perfect shape, the sphere. Thus, all the heavenly bodies are
perfect spheres, and their trajectories are circles, the most perfect
two-dimensional paths.
The problem for Aristotle is that it was known from observation that
simple circles did not account for the motions of heavenly bodies.
The planets, for example, occasionally exhibit retrograde motions.
Thus, Aristotle and others of his time tried to multiply the circles,
giving us epicycles, or circles inside of circles.
Claudius Ptolemy, writing in Alexandra in the 2 nd
this project, creating the greatest work of the ancient world, the
Almagest. This book contains a complete account of the motions
of all the objects in the night sky viewable without a telescope. To
accurately describe their trajectories, Ptolemy relied on some intricate
mathematical tools: epicycles, (multiple sets of circles inside circles),
eccentricities (squished circles), and ecliptics (off-center circles).
This was the state of science at the beginning of the Christian era.
In the 5 th century, Augustine found in Plato an intellectual
foundation for Christianity. Plato’s bifurcated world easily mapped
onto Christian theology, with a sinful, diseased world and an
eternal, perfect world of spirit.
Aristotle, for example, has no creation event. The circular orbits
time and will continue to do so. This would not do for Aquinas.
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