What is it that makes an object the thing that it is? Is it some kind of substance onto which properties are predicated? Can two (or more) things colocalize (there exists in a single region of spacetime both a thing I call my hand and a thing I call my fist)? In what follows, I am going to riff on some ideas I have for a theory of thingness.
Aristotle defined metaphysics as the study of Being qua Being – or, one might say, studying Being being Being. He says in book VII of his Metaphysics that Being is the individual instances of essence, which is the substance that defines what a thing is in-itself. Now, in our present time, we’ve narrowed down the primary substance further than our everyday sensible objects, down to subatomic particles. Can Aristotle’s philosophy be a useful lens to think about quantum mechanics?