Science can never dispense with Reality in the metaphysical sense of the term. — Max Planck

In many introductions to philosophy courses and textbooks, it is typical, to begin with Plato and Aristotle. The textbook or instructor always begins by comparing and contrasting the differences each thinker had regarding the ultimate nature of reality. This is done for good reason and is important for a foundational understanding of philosophy itself. I have covered these differences in my writings (here and here). It is correct to say that Plato believed in an ultimate transcendent realm of the forms (or universals, or Ideas), while Aristotle, his student, stressed the concrete nature of reality itself and the fact that forms and essences are in the objects themselves. In this sense, concrete means “grown together” or the “coalition of particular things”. For Aristotle, all physical objects have an essential nature to them, which makes them the kind of thing they are. “How else would we understand what a horse is without the nature of the horse inherently existing in the horse itself”? Aristotle would ask. A dead horse is a corpse, not a horse. Horseness is the formal constituent element of the horse just as humanity is the shared essential nature of President Trump, Queen Elizabeth II, and Dave Mustaine. Of course, essence is not limited to living things but that is a topic for another post. The broader point is that being is common to all things and I think that is Aristotle’s real answer to Plato. It is Plato’s misplaced universal. It is an answer which goes beyond the common textbook discussion.

Aristotle’s actual answer to Plato rests in a passage from his Metaphysics, Book VI, chapter 1. In his quest for the universal and the unity of being, Aristotle explains that the concept of being goes beyond mere genus and nature:

One might raise the question whether first philosophy is in any way universal or is concerned merely with some genus and some one nature. In the case of the mathematical sciences, their objects are not all treated in the same manner; geometry and astronomy are concerned with some nature, but universal mathematics to all. Accordingly, if there were no substances other than those formed by nature, physics would be the first science; but if there is an immovable substance, this would be prior, and the science of it would be first philosophy and would be universal in this manner, in view of the fact that it is first. And it would be the concern of this science, too, to investigate being qua being, both what being is and what belongs to it qua being.

Aristotle was right. All the immediate objects of human cognition are sensible things. In response to Plato’s notion of transcendent forms, Aristotle would reply that being itself is universal because it is common to all things. Being is common to all because it can be applied to any act of existing (in Aristotelian terms, “to be in act” means to exist). Additionally, to exist means to stand out of nothing, and to exist means to have being. Being is the universal that participates in all concretely existing things. That there is a metaphysical reality uniting all physical things should not be a surprise to modern readers. The German physicist and mathematician Max Planck said something very similar, “Metaphysical reality does not stand spatially behind what is given in experience, but lies fully within it” (Planck, Scientific Autobiography, 98, italics in the original). Planck was certainly a kindred spirit with Aristotle.

Aristotle teaches us, in response to Plato, that since metaphysics studies beings insofar as they are beings, the science of first philosophy will always have being in the concrete as its subject matter. The true universal of being in itself, understood in the concrete sense, is common to all. This, at least in part, is what unites the one with the many, and one of the most significant insights Aristotle shared with the Western intellectual tradition. Aristotle brings us the missing piece of reality which Plato missed. The study of being as being is the true science of metaphysics.