Metaphysics: Existence, Identity, and Modality
What this domain asks
Metaphysics examines what exists and what it is to exist. Candidates should command: ontology (categories of being), substance and property, universals versus particulars, identity and persistence through change, causation, free will and determinism, modality (possibility, necessity, possible worlds), and the mind-body problem.
Concepts to hold firmly
- Universals: realism (they exist independently), conceptualism (they are mental), nominalism (only particulars exist).
- Persistence: endurance (an object is wholly present at each time) versus perdurance (it has temporal parts).
- Causation: regularity, counterfactual, and interventionist accounts.
- Modality: necessity is truth in all possible worlds; contingency is truth in some but not all.
- Free will: compatibilism (freedom coexists with determinism), libertarianism (freedom requires indeterminism), hard determinism (no freedom).
Traps
- Confusing epistemic possibility ("for all I know") with metaphysical possibility.
- Treating compatibilism as denying determinism; it accepts determinism and redefines freedom.
- Mixing the mind-body options: dualism (two kinds), physicalism (one physical kind), idealism (one mental kind), panpsychism (mentality is fundamental and widespread).
- Assuming "substance" means physical stuff rather than a bearer of properties.
Rule of thumb
For any metaphysical question, first ask whether it concerns existence (what there is), essence (what it is), or persistence (how it stays the same). The answer usually follows from that classification.
Worked example
"A ship's planks are gradually replaced until none of the original remain. Which view says the ship persists because it retains a continuous causal history?" Answer: a persistence-through-continuity (four-dimensional or perdurantist) account, not mere material identity.