Abstract

ONE COULD SAY THAT THE SCIENCE OF METAPHYSICS was born of Parmenides wondering how to divide being. His reasoning, namely that nothing belonging to being could divide it, and that nonbeing, since it in no way exists, cannot divide anything, set the terms of the problem within which the great Western traditions of Platonic and Aristotelian metaphysics developed. In reply to this Parmenidian challenge to divide being, Plato writes in the Sophist of the participation of being in the other, and Aristotle in the Metaphysics of a pros hen equivocation of the name being. In response to the same seminal challenge to divide being, Thomas Aquinas speaks in the Quaestiones de veritate of modes of being and of modes of existing. Yet this terminology is barely acknowledged by Thomistic commentators.