 Galileo’s second new science, in Days Three and Four of the Two New Sciences, deals with the mathematical description of local motion and the laws governing it. This is now the motion of all matter, not just sublunary stuff, and the treatment takes the categories of time and acceleration as basic. Here is where Galileo enunciates his law of free fall, the parabolic path of projectiles, and other physical “discoveries” that would lay the foundation for modern physics (Drake 1999, v. 2).