What is metaphysics? A beginner’s guide to the study of what there is

Metaphysics is the part of philosophy that asks about the most general features of reality: what exists, what kinds of things there are, and what it is for something to be, to change, to cause something else, or to be possible. Where physics asks what the world is made of and how it behaves, metaphysics asks questions that physics takes for granted: what an object is, whether time passes, whether there are laws or only regularities, whether numbers exist.

It has a reputation for being obscure. Some of that is deserved. But most of its questions are ones people ask without knowing the name.

Where the word comes from

The word has an accidental origin. Aristotle wrote a set of treatises on what he called "first philosophy", the study of being as being, together with the first causes and principles of things. His editors, traditionally said to be led by Andronicus of Rhodes in the first century BCE, placed these treatises after his works on nature, the Physics. They became known as ta meta ta phusika: "the things after the physics". The title described a position on a shelf, and later readers took it to mean "beyond the physical".

Aristotle's own question, in the work we still call his Metaphysics, was what it is for anything to be at all, and his answer put substance, the independent individual thing, at the centre.

The main questions

Metaphysics today is usually divided into a handful of large questions, each of which has its own card on the site.

• What exists? This is ontology. Are there only physical things, or also numbers, properties, minds, possibilities? W. V. O. Quine began his essay "On What There Is" (1948) by noting that the ontological question can be put in three words, what is there?, and answered in one: everything. The difficulty is in the details. See 1.1 Ontology.
• What is a thing? Is an object a substance that has properties, or just a bundle of properties? Is a river a thing or an event? See 1.1.1 Substance Theory.
• What is causation? When one billiard ball moves another, is there a real connection, or, as David Hume argued, only one event regularly followed by another? See 1.4.2 Causation.
• What are time and change? Does only the present exist, or are past and future equally real? How does a thing survive change and remain the same thing?
• What is possible and necessary? Could the world have been different, and what makes that true? See 1.6 Modality.
• Are we free? If every event has a cause, is any choice really up to us? See 1.7 Free Will and Determinism.

Questions about the mind, about God and about the origin of the universe are also partly metaphysical, which is why metaphysics overlaps with the philosophy of mind, the philosophy of religion and cosmology.

Not only a Greek question

Metaphysics was not invented once. In India the Vaiśeṣika school drew up a list of categories (padārtha) of everything that can be known and named: substance, quality, action, universal, particularity and inherence, to which later thinkers added absence. Buddhist philosophers argued, against it, that what we call enduring things are streams of momentary events. In China the opening of the Daodejing plays on being and non-being (you and wu), and the young commentator Wang Bi, who died in 249 at twenty-three, read it as a claim that all things have their root in non-being. In the Islamic world Ibn Sīnā's distinction between a thing's essence and its existence shaped centuries of debate, in Arabic and then in Latin.

These traditions did not always ask the same questions, and it can mislead to force them into one box. But they show that the impulse to ask what is most basic in reality is not a European peculiarity.

Declared dead, and revived

In the twentieth century metaphysics had a near-death experience. Immanuel Kant had already argued, in the Prolegomena to Any Future Metaphysics (1783) and the Critique of Pure Reason, that reason overreaches when it tries to know things beyond any possible experience. The logical positivists went further. For A. J. Ayer, in Language, Truth and Logic (1936), a statement that could not be verified by experience and was not true by definition was literally meaningless, and much of traditional metaphysics failed the test. Rudolf Carnap argued in 1950 that questions such as "do numbers really exist?", asked outside any framework of language, were not real questions at all but practical choices about which framework to use.

The revival came from several directions. Quine argued that our best scientific theories already commit us to an ontology, so metaphysics is continuous with science rather than opposed to it. Peter Strawson's Individuals (1959) defended a "descriptive metaphysics" that sets out the basic structure of the way we actually think about the world. And from the 1970s work on possibility, necessity and identity, by Saul Kripke and David Lewis among others, made metaphysics one of the busiest areas of philosophy again. Whether its methods are as sound as its confidence suggests is itself a debated question, with its own card: 1.10 Meta-Metaphysics.

How to begin. You do not need special training to start, only a willingness to be puzzled by ordinary things. Is the flame on a cooker a thing, or something that keeps happening? Is a company that has replaced all its staff still the same company? Is the number seven anywhere? Our members ask questions like these every day in the Existence & being category, and many of the best threads were started by people who had never read a page of metaphysics.

If you want a book, Stephen Mumford's Metaphysics: A Very Short Introduction is a friendly first step. Then pick one question above, read its card, and post the objection that occurs to you first. That is how metaphysics has always been done.