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?