Aristotle said matter is the ultimate subject of predicates but it cannot exist on its own without any predicate or form for it would be nothing but still we need it as the substratum for predication. My question is why cannot there be a pure subject without any predicate?
Or alternatively why cannot we have a predicate existing as thing without any substratum? Why subject and predicate must go hand in hand?
Answer by Craig Skinner
We agree that the everyday physical world consists of things + properties (subjects+predicates in your terminology; substances+ accidents in Aristotle’s).
So your first question is why cant we have a thing with no properties? If we say a thing is the bearer of its properties, and strip away all the properties, we are left with a bare particular as the substratum. But what kind of entity could this be? If the substratum has no properties whatsoever, we could exchange the substrata of a dog and a stone say, and add all the properties back in. But now the entity with all the dog properties is really a stone. Absurd. An alternative view is the bundle theory which says that a thing just is all of its properties: take these away and there is nothing left. But, in that case, what is it that binds these properties together to make a particular thing? I think the substratum theory and the bundle theory are incoherent. No, the bearer of the properties is the thing itself, which is prime matter (potential) taking the form of that particular thing, as Aristotle says.
Aristotle correctly called a thing (substance) a “being in itself”, a self-standing item which cant be predicated (or be a property) of anything else. A property (predicate, accident, quality), on the other hand, can only be “present in another” i.e. as a feature of a thing. By definition a property is not, and cant be, a thing. Thus you never come across a big or a black or an old, there always has to be a big, black or old something. Plato, by the way, thought that properties in the everyday world were instances of universals which exist in another heavenly world of Forms. So the black in my cat instantiates the Form of the Black (blackness). Even if every black thing in the world were destroyed, the Form of the Black would remain, just uninstantiated. But Aristotle thought blackness existed only as and in its instances. “Goodbye to the Forms, for they are nonsense” he said. I’m with Aristotle — properties exist in things, not prior to them, in rebus rather than ante rem, as the philosophers of old put it.
Finally, Aristotle’s metaphysics of potentiality/ actuality, substance/ accidents, matter/ form, essence/ existence, and four causes/ causal powers is increasingly recognized as the framework underlying physics and biology, after a long period of misrepresentation and neglect beginning with early moderns such as Hobbes, Descartes and Locke, and I’m pleased you’re interested in it.