Il "libro della natura" di Galileo

Published exactly four centuries ago, Galileo’s Il Saggiatore (1623) originated from a dispute with Jesuit mathematician Orazio Grassi over the nature and motion of comets that appeared in the second half of 1618. Il Saggiatore, however, is much more than a work on comets. In numerous long digressions, Galileo analyzes various physical phenomena, where he expounds, for example, his conception of the structure of matter, based on the distinction between primary and secondary qualities, and explains the corpuscular nature of heat. In this way, Galileo took the opportunity to present his new natural philosophy, which, through a rigorously mathematical (according to the famous image of the book of nature) and empirically grounded approach, was a viable alternative to the traditional Aristotelian-scholastic system.