Aristotle :: essays research papers

To the modern reader, Aristotles views on astronomy, as presented in Metaphysics, Physics, De Caelo (On the Heavens) and Simplicius Commentary, will most believably seem very bizarre, as they are based more on a priori philosophical speculation than empirical observation. Although Aristotle acknowledged the importance of "scientific" astronomy - the study of the positions, distances and motions of the stars - he nevertheless treated astronomy in the abstract, linking it to his overall philosophical world picture. As a result, the modern attribute between physics and metaphysics is not present in Aristotle, and in station to fully appreciate him we moldiness try to abandon this pre-conception. Aristotle argued that the universe is global and finite. Spherical, because that is the most perfect shape finite, because it has a center, viz. the center of the earth, and a body with a center cannot be infinite. He believed that the earth, too, is a sphere. It is relatively sma ll compared to the stars, and in contrast to the supernal bodies, always at rest. For cardinal of his proofs of this latter point, he referred to an empirically testable fact if the earth were in motion, an reviewer on it would see the fixed stars as moving, just as he now observes the planets as moving, that is from a stationary earth. However, since this is not the case, the earth must be at rest. To prove that the earth is a sphere, he produced the stock that all earthly substances move towards the center, and thus would eventually have to body a sphere. He also used evidence based on observation. If the earth were not spherical, lunar eclipses would not show segments with a veer outline. Furthermore, when one travels northward or southward, one does not see the equivalent stars at night, nor do they occupy the same positions in the sky. (De Caelo, Book II, chapter 14) That the celestial bodies must also be spherical in shape, can be determined by observation. In the case o f the stars, Aristotle argued that they would have to be spherical, as this shape, which is the most perfect, allows them to retain their positions. (De Caelo, Book II, chapter 11) By Aristotles time, Empedocles view that there are four basic elements - earth, air, fire and water - had been generally accepted. Aristotle, however, in summing up to this, postulated a fifth element called aether, which he believed to be the main instalment of the celestial bodies.