Ontology and Metaphysics: Being, Substance, and Reality
Core vocabulary
Candidates must handle the distinctions between being (that something is), essence (what it is), existence, substance (that which underlies and supports properties), attribute/property, mode, accident, and relation. Know the difference between monism, dualism, and pluralism; between materialism, idealism, and dualism; and between realism, nominalism, and conceptualism about universals.
Historical anchors
Be able to place: Parmenides (being is one, change is illusion), Plato's theory of Forms (two worlds, participation), Aristotle's hylomorphism (form + matter, substance as composite, four causes), Descartes' substance dualism (thinking and extended substance), Spinoza's monism (one substance, attributes of thought and extension), Leibniz's monads, Kant's distinction between phenomena and noumena, and modern debates on possible worlds and supervenience.
The central problems
The classical problems are: the one and the many, being and becoming (is change real?), the problem of universals, substance vs. process, causation (is it a real power or a regular succession?), and necessity vs. contingency.
Traps
Frequent errors: (a) equating "substance" with "physical stuff" - in Aristotle it is a this-something; (b) confusing essence with existence (existentialism inverts the classical priority); (c) treating Kant's noumenon as a thing we could know; (d) confusing idealism (reality is mind-dependent) with solipsism.
Rule of thumb
For any metaphysical claim, ask: what is being asserted to exist, and on what grounds? Then check whether the claim is about what there is (ontic) or about the categories in terms of which we say what there is (ontological framework).
Worked example: "Only particulars exist." This is a nominalist ontological thesis; it denies the existence of universals but need not deny properties as tropes. State the thesis precisely before evaluating it.