From the very beginnings of medieval thought about the year 1200 until 1687, the year Isaac Newton published his monumental Principia, the Aristotelian-Ptolemaic geocentric cosmology dominated intellectual debate about the nature of our universe. Professor Grant is examining how the Aristotelian system managed to persist for nearly half a millennium. To understand this phenomenon is to understand the ability of received views to persist, even in the light of contradictory evidence. Or, better, to understand the persistence of the Aristotelian system is to understand how a scientific theory can adapt to accommodate new views and to understand how extraordinarily difficult it is to overthrow entrenched views. By undertaking this study, Professor Grant is thus shedding light on one of the most important issues in science studies: how science changes--and why it does not change. Professor Grant has found that the nearly 500 year period can be divided into two parts: 1200-1500 when the Aristotelian view was overwhelmingly dominant and had no viable rivals. The second phase from 1500-1687 was one in which a number of rival cosmologies appeared ranging from the Platonic views to those of the hermetic tradition of Hermes Trismagistus. He has found that, even if Copernicus had never written De revolutionibus, a significant debate about the earth's possible axial rotation and orbital motion would have occurred. Yet in 1543, Copernicus did publish his revolutionary views and the remaining century and a half of Aristotelian cosmology was one of trying to accommodate the Aristotelian system to the discoveries which emerged in the 16th and 17th centuries--from Brahe's new observations of the planets and stars to Galileo's telescopic discoveries. The results of Professor Grant's study will be a massive history of Aristotelian cosmology. This study will have major importance for studies in the history and the philosophy of science which are concerned with the central issues of scientific change.
