 In Aristotle’s system, physics was not mathematized although causal reasonings were proper to it. However, Aristotle also discussed extensively the so-called mixed sciences, such as optics, harmonics, and mechanics, characterizing them as “the more physical of the mathematical sciences”. There is a relation of subordination between these mixed sciences and areas of pure mathematics. For instance, harmonics is subordinated to arithmetic and optics to geometry. Aristotle is in no doubt that there are mathematical explanations of physical phenomena: