Metaphysics
first philosophy
The branch of philosophy that asks what fundamentally exists and what its nature is.
In practice
A ship has every plank replaced over thirty years. Deciding whether it is the same ship is a metaphysical question about identity, and the same question governs whether a company that has replaced every employee is the same company.
The common mistake
Using 'metaphysical' to mean mystical or unverifiable. In philosophy it names a set of precise structural questions, many of which are pursued alongside physics and logic.
Metaphysics asks what exists and what it is like at the most general level. It takes up the questions that the particular sciences assume rather than investigate: what a thing is, what makes it the same thing over time, what causes are, and whether anything exists necessarily.
The parts of the subject
Ontology is the study of what there is — objects, properties, events, numbers, minds. A recurring dispute is whether universals such as redness exist in their own right or only as a way of grouping particular things.
The theory of substance asks what it is for something to be a thing at all rather than a bundle of qualities. Aristotle held that a substance is what underlies change and persists through it; Hume doubted that anything beyond the bundle of qualities is ever encountered.
Causation asks what the relation between cause and effect consists in, and determinism asks whether that relation fixes every event in advance — which is where metaphysics meets free will.
The word and the reputation
The name is an accident of cataloguing. Aristotle's editors placed these books after the Physics, and ta meta ta physika meant the volumes that came next. The subject acquired a reputation for detachment from evidence, and the logical positivists of the 1920s argued that its claims were untestable and therefore empty. That verdict has not held: contemporary metaphysics works closely with physics and logic on questions about time, parts and wholes, possibility and identity.
Why the questions survive
Metaphysical commitments are difficult to avoid. Anyone who says an object survived a repair, that an event caused another, or that a person is the same person they were at ten, is using a metaphysical claim. The field makes those commitments explicit and examines whether they are consistent.
Concept web
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What is metaphysics?
Metaphysics is the branch of philosophy concerned with what exists and the most general features of reality — objects, properties, causation, time, identity, and possibility.
What is the difference between metaphysics and physics?
Physics investigates the behavior of physical systems by observation and experiment. Metaphysics examines the concepts physics assumes, such as what an object is, what causation consists in, and what it means for something to persist.
Why is it called metaphysics?
From the Greek phrase meaning 'after the Physics'. Aristotle's editors used it to label the books placed after his Physics in the collection, and the name later came to describe the subject matter itself.