Metaphysics
Metaphysics
Metaphysics is the branch of philosophy that investigates the fundamental nature of reality — what exists, what it is made of, and how things relate to one another. Aristotle called it "first philosophy" and defined it as the study of "being qua being."
Central Questions
- What kinds of things exist? (ontology)
- What is the relationship between mind and body?
- Do abstract objects — numbers, properties, universals — really exist?
- What makes something the same entity over time (personal identity)?
- Is causation real, or merely a projection of our minds?
- Is there a first cause or ultimate ground of existence (theology)?
- Do we have Free Will, or is everything determined?
The Problem of Universals
One of the oldest metaphysical debates: do general properties (redness, triangularity) exist independently of particular things?
- Realism — universals exist independently of particulars. See Plato's The Forms.
- Nominalism — only individual things exist; universals are merely names we apply
- Conceptualism — universals exist as concepts in the mind but not in external reality
Major Positions on the Nature of Reality
| Position | Claim | Key Figure |
|---|---|---|
| Materialism / Physicalism | Only physical things exist | Marx, modern science |
| Idealism | Reality is fundamentally mental or spiritual | Hegel |
| Dualism | Mind and body are fundamentally distinct substances | Descartes |
| Monism | Reality is ultimately one kind of thing | Spinoza |
| Pluralism | Reality consists of many irreducible substances | Aristotle |
Mind and Body
Descartes proposed substance dualism: mind (res cogitans) and matter (res extensa) are two fundamentally different substances. This raises the interaction problem: how do they causally affect each other?
Modern philosophy of mind grapples with this through:
- Physicalism — mental states are physical brain states
- Functionalism — mental states are defined by causal roles, not physical composition
- Property dualism — one substance, but irreducible mental and physical properties
See Consciousness for the contemporary version of this debate.
Causation and Necessity
Hume famously denied that we ever perceive necessary causal connection — we only observe constant conjunction (A is regularly followed by B). Kant responded by arguing causation is a category of the understanding that we impose on experience, not something we read off it.
Personal Identity
What makes you the same person over time? Hume held there is no persistent self — only a "bundle" of perceptions. Locke grounded identity in psychological continuity and memory. Descartes held the soul as the enduring self.
Cosmological and Theological Questions
- Does God exist? (Cosmological, ontological, and teleological arguments)
- Did the universe have a beginning, or is it eternal?
- Is there purpose (telos) in nature? Aristotle said yes; Hume was skeptical.
Related Topics
- Epistemology — what we can know about metaphysical questions
- The Forms — Plato's answer to the problem of universals
- Consciousness — the hard problem of mind and reality
- Free Will — determinism and the metaphysics of agency
- Dialectics — Hegel's dynamic metaphysics
- Phenomenology — Metaphysics approached via first-person experience
- Descartes — substance dualism
- Hegel — Absolute Idealism
- Hume — skepticism about causation and substance
