The Illustrated Printed Page as a Tool for Thinking and for Transmitting Knowledge. The Case of the Theoricae Planetarum

Abstract

AbstractDuring the early modern period, astronomy underwent a profound transformation in the way it was taught, as the response of an enlarged readership took on more and more importance. This change notably concerned the use of images and diagrams. TheTheoricae planetarum, especially Peuerbach’sTheoricae novae planetarum, are a privileged example in this respect, for they served a particularly large range of functions. They were mnemonic tools and visual glossaries, and an essential element in Peuerbach’s pedagogical approach. They had a documentary role, as they gave plausible representations of the celestial spheres; they could be used as proofs of the soundness of a “theory,” or could simply help to follow a geometrical demonstration. Some of them were small-scale models designed to serve as tools for the mind to better grasp the complex combination of movements in what was then calledmachina mundi. All these figures, and their power to exercise the mind, were well suited to a period when more and more astronomers were involved in imagining, drawing, and comparing hypothetical models of planetary movements.