Works Cited

These [Pythagorean] studies are not to be pursued in any utilitarian spirit, but in order to prepare [the young man's] mind for the vision of eternal things. In astronomy, for example, he is not to trouble himself too much about the actual heavenly bodies, but rather with the mathematics of the motion of ideal heavenly bodies. This may sound absurd to modern ears, but, strange to say, it proved to be a fruitful point of view in connection with empirical astronomy...

The apparent motions of the planets, until they have been very profoundly analysed, appear to be irregular and complicated, and not at all such as a Pythagorean Creator would have chosen... The problem thus arose: is there any hypothesis which will reduce the apparent disorderliness of planetary motions to order and beauty and simplicity?... Aristarchus of Samos found such a hypothesis: that all the planets, including the earth, go round the sun in circles. This view was rejected for two thousand years, party on the authority of Aristotle... It was revived by Copernicus, and its success might seem to justify Plato's aesthetic bias in astronomy. Unfortunately, however, Kepler discovered that the planets move in ellipses, not in circles, with sun at a focus, not at the centre; then Newton discovered that they do not move even in exact ellipses.


Bertrand Russell, The History of Western Philosophy