Once the human intellect creates symbols from reality, those symbols or words can be manipulated and catalogued to increase our understanding of reality. Aristotle’s ten categories of being classify words in relationship to our knowledge of being. These metaphysical categories have their exact counterpart in the ten categories or praedicamenta 15 of logic, which classify our concepts, our knowledge of being. Every being exists either in itself or in another. If it exists in itself, it is a substance. If it exists in another, it is an accident. We distinguish nine categories of accident; these, with substance, constitute the ten categories of being.