One place to focus on in order to understand the difference between ancient and modern physics is the different answers they give to the question “what is in motion?” For all the physicists after Newton- and to this day- the answer is “a body”: every body perseveres in a uniform state of motion or of rest, and inertia belongs to the moving or resting body. For Aristotle, the answer to the question “what is in motion?” is a mobile (Aristotle will insist that mobiles are bodies as well, even proving it in book VI of the Physics). While this difference seems small, it is in fact immense. For Aristotle the thing that moves is characterized by its “ability” (the -ble suffix); for Newton it is characterized by its act or form. For Newton, what moves is a per se measurable thing, for Aristotle it is not. For Aristotle, motion is a certain actuality of a potency (namely, the potency of being a mobile, which is obviously an ability to move); for Newton, motion is the status of a body. Using Aristotle, one can prove Newton, using Newton, one cannot come to Aristotle.
Newton, in fact, could have made a contribution of immeasurable worth to philsophy if he had said something like this in the Proemium of his Principia: I have treated only of motion as it is understood after Book VI of Aristotle’s Physics, where the mobile is proved to be a body. All that comes before this, or follows directly from it, I neither affirm nor deny.
What’s more, he would have said something true.