Abstract
If a metaphysics identifies transcendental principles with formal principles, the inevitable result will be a reductionist collapse, that is, a theory of the nature of reality that will exclude as inessential significant differences among existing things. To avoid this result, we must take some such material differences (those, for example, that distinguish physical, biological and mental phenomena from one another) as transcendental in nature. This produces a metaphysics in which the concept of ontological emergence is central—a metaphysics that will depend essentially on the material content of the natural sciences. While both Aristotle and Hegel provided such a metaphysics, they did not, I argue, accept one of its most important consequences—that it must be as incomplete as our scientific knowledge of these material differences. I examine this failure and suggest some areas in which contemporary scientific conceptions may contribute to a more contemporary metaphysics.