The present does not seem to me to be an opportune time to enter into the investigation of the cause of the acceleration of natural motion, concerning which various philosophers have produced various opinions, some of them reducing this to approach to the center; others to the presence of successively less parts of the medium remaining to be divided; and others to a certain extrusion by the surrounding medium which, in rejoining itself behind the moveable, goes pressing and continually pushing it out. Such fantasies, and others like them, would have to be examined and resolved, with little gain.This sounds remarkably similar to Newton's famous "Hypotheses non fingo" ("I feign no hypotheses"), said in regard to the causes of gravitational attraction. He offered no hypotheses on the deeper nature of gravity, and his decision to be very focused was part of why he was so successful. Similar things can be said of Galileo's analysis of free fall.
Tuesday, March 27, 2018
OK, I'm finally reading Galileo's Two New Sciences, and while I don't have much time now to blog about it, I want to note that on pages 158-159 of the Stillman Drake translation (apparently page 202 of the original), Salviati says: