In this concise book I explore the significance of the study of the celestial world for Aristotle's science of nature. I argue that, while Aristotle insists that the celestial world is radically different from the sublunary world, Aristotle yet conceives of the natural world as one department of reality with sufficient unity to be the object of a single science. I also investigate the source of the discontinuity between celestial and sublunary natures and argues that the conviction that the natural world exhibits unity without uniformity is the ultimate reason for Aristotle's claim that the heavens are made of a special body, unique to them.
This book presents Aristotle as a totally engaged, systematic investigator whose ultimate concern was to integrate his distinct and specific investigations into a coherent interpretation of the world we live in, all the while mindful of human limitations to what can ultimately be known. I read in Aristotle the ambition of an extraordinarily curious mind and the confidence that that ambition has been largely fulfilled.