so, no Physics !
Aristotle's cosmological work On The Heavens is the most influential treatise of its kind in the history of humanity. It was accepted for more that 18 centuries from its inception (around 350 B.C.) until the works of Cusa and Copernicus starting around 1450.
In this work Aristotle discussed the general nature of the cosmos and certain properties of individual bodies.
The idea that all bodies, by their very nature, have a natural way of moving is central to Aristotelian
cosmology. Movement is not, he states, the result of the influence of one body on another so, no Physics !
Movement is therefore endowed to bodies. Is this science?
Some bodies naturally move in straight lines, others naturally are at rest.
But there is yet another natural movement: the circular motion.
By logic: since to each motion there must correspond a substance, there ought to be some bodies that naturally move in circles. Aristotle proclaims that such things that move in circles are the heavenly bodies as they are made of a more exalted and perfect substance than all earthly objects. |
Note the desciptors here: Exalted and Perfect
Since the stars and planets are made of this exalted substance and then move in circles, it is also natural, according to Aristotle, for these objects to be spheres also. The cosmos is then made of a central earth (which he accepted as spherical) surrounded by the moon, sun and stars all moving in circles around it. This conglomerate he called ``the world''.
(The Finite Crystalline Sphere Universe)
The initial motion of these spheres was caused by the action of a prime mover which acts on the outermost sphere of the fixed stars; somehow, however, this action is communicated to the other spheres and they move as well, but at different rates, since that is what the observations demand.
Aristotle also asserts that the world did not come into being at one point, but that it has existed, unchanged, for all eternity (it had to be that way since it was perfect .
Still, since he believed that the sphere was the most perfect of the geometrical shapes, the universe did have a center (the Earth) and its material part had an edge, which was ``gradual'' starting in the lunar and ending in the fixed star sphere.
Beyond the sphere of the stars the universe continued into the spiritual realm where material things cannot be.
This is in direct conflict with the Biblical description of creation , and an enormous amount of effort was spent by the medieval philosophers in trying to reconcile these views (and, for which, of course, no reconciliation is possible).
Discussion question: What is a potential observational/physical problem with the Universe having an infinite age?