What Metaphysics Asks

Physics can tell you what a table is made of, how it conducts heat, and what happens to it at two thousand degrees. It does not tell you whether the table is a thing in its own right or just some particles arranged tablewise, whether it is the same table it was before you replaced the leg, or whether the brownness of the table is itself something that exists in addition to the table. Those questions are not gaps in physics waiting to be filled by better instruments. They are questions about what the physics is a description of.

The name is an accident

The word comes from the arrangement of a book rather than from any doctrine. Aristotle left fourteen books on these questions, and an editor, in all probability Andronicus of Rhodes, gave them a collective title well over a century after Aristotle's death. Ta meta ta phusika means "the ones after the physics", which is where they sat in the edition.

Aristotle himself never used the word. He called the enquiry by several names, among them first philosophy, first science, wisdom, and theology.

Nothing about the accident of the name matters to the content. It is worth knowing only because "metaphysics" is sometimes read as "beyond the physical", which suggests a subject about spirits and hidden realms. That reading has no basis in the title's origin, and it does not describe what the books are about.

What makes a question metaphysical

There is no sharp test, but there is a reliable symptom: the question survives every possible answer to the corresponding scientific question.

Take persistence. A biologist can tell you which molecules in your body have been replaced since you were seven, and the answer is nearly all of them. That settles the chemistry and leaves the original question untouched: are you the same person who was seven, and if so, what makes you so, given that the material is gone? No further measurement helps, because no possible measurement result would decide it. What is needed is an account of what identity over time consists in.

The pattern recurs. Causation: physics gives you laws relating earlier states to later ones, and leaves open whether causing is anything more than being related by such a law. Possibility: chemistry tells you this glass did not shatter, and leaves open what it means that it could have. Composition: the sciences describe parts and describe wholes, and do not say what has to happen for some parts to constitute a whole.

Categories

The oldest project in the subject is sorting: taking the whole inventory of what there is and dividing it into the most general kinds.

The point of a category scheme is not tidiness. It is that different categories answer to different questions. Ask of an object where it is, how long it has lasted, what it is made of. Those questions have answers. Ask the same of the number seven and they do not, not because the answers are unknown but because the questions do not apply. A category scheme is a claim about which questions make sense about which things.

Aristotle's own list ran to ten, beginning with substance and continuing through quantity, quality, and relation. Later schemes differ, and some philosophers get by with very few. What the schemes share is the ambition: an account of the joints along which reality divides, rather than the divisions our vocabulary happens to have.

The relation to ontology

The two words are often used interchangeably, and some writers treat ontology as the whole of metaphysics. This site keeps them apart along a practical line rather than a principled one.

Ontology asks the inventory question: what is on the list, and how do we tell. Metaphysics takes that question in and adds the structural ones: what it is for a thing to have a property, what makes two descriptions descriptions of the same thing, what change is, what a cause is, and what it means that things could have gone otherwise. On this division, ontology is the part of metaphysics concerned with existence, and the ontology ladder on this site runs alongside this one for exactly that reason.

The division is a convenience of exposition. Nobody should be argued out of a position on the strength of it.

Where this tier goes

The next article takes up what to say about things that do not exist, which is where the inventory question bites hardest. After that the tier builds the vocabulary the rest of the subject runs on: objects and their properties, the abstract and the concrete, identity through change, the Ship of Theseus as the test case for all of it, causation, possibility and necessity, and finally the distinction between what a thing has to be and what it merely happens to be.

Each article assumes only the ones before it. None of them assumes an answer.