On Wonderful Machines: The Transmission of Mechanical Knowledge by Jesuits*

Abstract

This paper attempts to draw attention to non-conventional but popular modes of transmitting scientific knowledge in Jesuit institutions in the 17th century. The particular case study focuses on a fictive dialogue between Galileo, Mersenne and Paulus Guldin on the power needed for moving the huge globe of the earth by mechanical means. The dialogue was written by a Jesuit mathematician named Paolo Casati (1617–1707) and published in 1655. Apparently, Casati offers his readers an idealized representation of a real event that took place at the Collegio Romano, where explanation of mathematical problems in a kind of public ritual used to take place once or twice a month in presence of philosophers, theologians, visitors and students. My analysis of some parts of Casati’s Terra Machinis Mota exemplifies the Jesuits’ success to accommodate the project of Renaissance practical mathematicians – the fusion of the pseudo-Aristotelian interest in machines with the mathematical approach of Archimedes – to the framework of the traditional mixed mathematical science that legitimized it and spread it among wide audiences. Casati’s text demonstrates how at least some Jesuit mathematicians were ready to adopt Galileo’s early mechanical project. However, moving from an analysis of the contents of mechanical knowledge popularized in this text to its analysis on the rhetorical level reveals the unbearable tensions by which Jesuit scientific culture was actually torn. The rhetorical choice to construct a representation of a seemingly friendly dialogue between the quasi-heretic Galileo, the Minim friar Mersenne and the suspected character of the Jesuit Guldin reveals the strategies by which Galileo’s heretic image was tamed in order to fit the Jesuits’ needs to construct themselves an enlightened public image.