The central thesis of this paper is that Aristotle's major innovation in the field of natural science as developed in Book I of the Physics is the concept of στέρησις, not that of ὑποκείμενον. The argument for this thesis has three parts.
First, I aim to prove that this concept is necessary for explaining cases of non-random coming to be. The second point is that Aristotle ascribes the concept of ὑποκείμενον to his predecessors.
My third goal is to showcase that Aristotle uses the concept of στέρησις to solve a longstanding puzzle about being.