Platos Design Systems - Essay Example

? Plato's design systems that reduce the apparent irregularities in the motions of the planets to regular motions in perfectly regular cycles Institution Plato's design systems that reduce the apparent irregularities in the motions of the planets to regular motions in perfectly regular circles The history of classical astronomy tends to emphasise the development of mathematical astronomy and the origin of astronomical instrumentation. The conventional structure of the classical world finds its earliest extant form in Plato's works in which we encounter a geocentric cosmos with the earth at the centre, surrounded by crystalline spheres on which planets rotated, with the fixed stars at the outermost limit. Plato's later dialogues abound in mathematical allegories. Timaeus begins with a very long one, Statesman contains a short one, the Republic has three, and both Critias and Laws are permeated with them from beginning to end. When Plato died in 347 B.C. his pupils and friends immediately began to argue about these mathematical constructions and about Plato's purpose in using them for models of souls, cities, and the planetary system. By the beginning of the Christian era much of Plato's mathematics had become a riddle. Many rivals clamored for recognition as the “single harmony” Socrates heard from the planets.1 A certain number which he confidently proclaimed “sovereign” in political theory was labelled “numero Platonis obscurius” by Cicero (c. 100 A.D.), with the hearty concurrence of later scholars; an interpretation which Nicomachus promised at about this time was either lost or never written. By the fifth century A.D., Proclus, one of the last to head the Platonic Academy, could not pretend to understand Plato's arithmetic, although he was astute enough to label as spurious a then popular interpretation of the Timaeus “World-Soul.” Down through history Plato's mathematical allegories defied Platonists either to reconstruct his arithmetic or to find in it the implications he claimed for it. In 1937 Francis Cornford, concluded that the difficulties which arise in abstracting a planetary system from Plato's musical arithmetic in Timaeus were due to a metal “armillary sphere” which the Academy possessed. “Plato probably had it before him as he wrote.”5 In 1945, in his translation of the Republic, Cornford not only omitted “the extremely obscure description” of Socrates' “sovereign number,” but he also allowed himself to “simplify the text” of the tyrant's allegory. The theoretical cosmic psychologies proposed by Plato found practical application in the work of Claudius Ptolemy. Ptolemy has a claim to being the most influential of classical astronomers on account of the respect with which his encyclopaedic work on mathematical astronomy, the Syntaxis, or Almagest. While the Almagest, is usually the centre of attention when Ptolemy's astronomy is examined, if his cosmology is to be understood on its own terms, its purpose cannot be understood independently of two of his other works, the Harmonics and the Tetrabiblos, in both of which he raised the soul's relationship with the stars. Ptolemy his work in two phases, the first was concerned with the measurement of celestial positions and the second with the measurement of their effects which was foundations of western astrology. Those effects might be felt in the natural world but also in the psychological, the realm of the soul. Ptolemy's psychological astronomy can be divided into two forms, the contemplative and the analytical. Kepler was also influenced by Plato's Ideas. He used Plato's regular solids to describe planetary motion. He assigned the cube to Saturn, the tetrahedron to Jupiter, the dodecahedron to Mars, the icosahedron to Venus, and the octahedron to Mercury. He is remembered in the history of sciences for his three planetary laws. Kepler's first law abolishes the old axiom of the circular orbits of the planets. The second law breaks with another axiom of traditional astronomy, according to which the motion of the planets is uniform in swiftness. The Ptolemaic tradition in astronomy was aware of this difficulty and applied a device for saving the “appearance” of acceleration: the equant. Copernicus insisted on the necessity of the axiom of uniform circular motion. Ptolemy's equant was understood by Copernicus as a technical device based on the violation of this axiom. Kepler affirms the reality of changes in the velocities of the planetary motions and provides a physical account for them. Since Greek times, the accepted description of the planetary system had been a geometrical one, known as the Ptolemaic theory, which supposed that the Earth was fixed at the centre of the universe, with the Moon, the Sun, and the five known (naked-eye) planets revolving round it. Geocentricity was obviously in accordance with the evidence of the senses - as well as being the only arrangement acceptable to the Church - by contrast with the heliocentric configuration, which was proposed by Copernicus. Copernicus was a confirmed Platonist who, like Plato, firmly believed that the planets executed perfectly uniform circular motion! It was Ptolemy, one of the staunchest proponents of a geocentric model of the solar system, who had actually defied Plato by adopting the equant construct in his unwieldy system in order to force the planets to travel at varying speeds along perfect circular paths. Thus, Copernicus’ breakthrough was actually something of a throwback—he managed to re-institute Plato’s perfect, uniform circular motion requirement, albeit in circles that ran around the Sun instead of the Earth. His scheme of motion, though in principle simpler than that of Ptolemy, was still riddled with the ferris-wheel-like structure of epicycle turning upon deferent. He had no choice but to adopt such a cumbersome structure if he was to obtain some degree of agreement between the observed and predicted positions of the planets—and insist that the planets obey the Platonic dictate. In all, his heavenly model required some forty-eight epicycles, eight more than Ptolemy's! Koestler was referring to the Osiander’s preface when he talked about the scandal of the preface. Koestler expresses the views that Osiander’s preface give the wrong and absurd ideas of what Ptolemy and Copernicus attempted to communicate in their ideas (Koestler, 1990). The preface stated that Ptolemy hypothesized that the earth was at rest while Copernicus hypothesized that the earth was in motion. However, this was not actually what Ptolemy and Copernicus hypotheses were really about.  Their hypothesis involved a lot more than that. Ptolemy believed that the earth was at the center of the system and the other bodies were revolving around it. Copernicus changed the hypothesis by stating that sun was at the center and other bodies revolving around it. Therefore the preface was misleading. Reference Koestler A. (2010). The Sleepwalkers: A History of Man’s Changing Vision of the Universe. USA. Penguin Publisher Read More