Metaphysics and Epistemology
Metaphysics and epistemology are the two most foundational areas of philosophy. Metaphysics asks what there is — the ultimate nature of reality. Epistemology asks what we can know and how — the nature, sources and limits of knowledge.
Aristotle's name for 'first philosophy' — the inquiry into 'being qua being'. The label 'meta-ta-physika' was coined by an early editor (Andronicus of Rhodes, 1st c. BCE) for the books placed 'after the Physics' in the corpus. Major sub-fields include ontology, cosmology, philosophy of mind, philosophy of religion and modal metaphysics.
Metaphysics — central questions
- What kinds of things exist? (ontology)
- What is the nature of objects and properties? (substance, universals)
- What is the nature of space, time and causation?
- What is the relationship between mind and body?
- Do we have free will?
- Is there a God? (philosophy of religion)
- What grounds modal claims about necessity and possibility?
Substance and property
The question "what is substance?" runs from Aristotle to Kant:
- Aristotle — primary substance is the individual (this man, this horse); essence (ousia) determines what it is.
- Descartes — three substances: God (infinite), mind (res cogitans), body (res extensa).
- Spinoza — one substance, Deus sive Natura.
- Leibniz — infinite monads.
- Locke — substance as "I-know-not-what" supporting properties.
- Hume — bundle theory; no enduring substance, only collections of properties.
- Kant — substance is a category of understanding applied to phenomena.
Universals and particulars
The problem of universals asks: do properties shared by many particulars (redness, justice) exist independently?
- Plato — universals are eternal Forms in a separate realm (extreme realism).
- Aristotle — universals exist in re — in particulars (moderate realism).
- Medieval nominalism (Roscelin, Ockham) — universals are mere names; only particulars exist.
- Conceptualism (Abelard, Locke) — universals are mental concepts.
- Modern realism (Russell, Armstrong) — universals exist as instantiated properties.
Mind-body problem
Contemporary debate inherits Descartes' dualism:
| Position | Claim |
|---|---|
| Substance dualism | Mind and body are distinct substances (Descartes) |
| Property dualism | One substance, two types of properties (Chalmers 1996) |
| Idealism | Only minds and ideas exist (Berkeley) |
| Materialism / physicalism | Only physical things exist; mind is brain |
| Type identity theory | Mental states = brain-state types (Smart 1959) |
| Functionalism | Mental states defined by functional role (Putnam 1967) |
| Eliminative materialism | Folk-psychological terms refer to nothing (Churchland) |
| Anomalous monism | Token identity without psychophysical laws (Davidson) |
The hard problem of consciousness (Chalmers 1995): why is there subjective experience at all?
- Ontology is the branch of metaphysics dealing with what kinds of things exist.
- Realism vs. anti-realism is a recurring axis — about universals, ethics, mathematics, science.
- Causation debate: regularity theory (Hume) vs. counterfactual (Lewis 1973) vs. powers (Cartwright).
- Modality — necessity, possibility — analysed via possible worlds (Kripke, Lewis 1986).
Epistemology — central questions
- What is knowledge? (analysis of knowledge)
- What can we know? (scope of knowledge)
- What are the sources of knowledge? (reason, sense, testimony, intuition)
- What justifies belief? (theories of justification)
- How do we respond to scepticism?
The classical (JTB) definition
Plato in Theaetetus and Meno proposed the classic analysis: knowledge is justified true belief (JTB). S knows that p iff:
- p is true.
- S believes that p.
- S is justified in believing that p.
Edmund Gettier's 1963 paper "Is Justified True Belief Knowledge?" produced counterexamples showing JTB insufficient. Responses include:
- Fourth condition approaches — no false lemmas, defeasibility.
- Reliabilism (Goldman 1967) — replace justification with reliable process.
- Virtue epistemology (Sosa, Zagzebski) — knowledge from intellectual virtue.
- Knowledge-first epistemology (Williamson 2000) — knowledge as primitive.
Sources of knowledge
| Source | Description |
|---|---|
| Perception | Sense-experience; empiricist core (Locke, Hume) |
| Reason | A priori intuition; rationalist core (Descartes, Leibniz) |
| Memory | Retained past knowledge; presumptive reliability |
| Testimony | Knowledge from others; Hume, Reid, modern social epistemology |
| Introspection | Knowledge of one's own mental states |
| Intuition | Direct apprehension of truths (Plato, Husserl) |
| Revelation | Religious knowledge from sacred texts (Plantinga 2000) |
Theories of justification
- Foundationalism: basic beliefs ground non-basic beliefs (Descartes, Aristotle).
- Coherentism: beliefs justified by membership in coherent set (Bonjour).
- Infinitism: infinite chain of reasons (Klein).
- Externalism vs. internalism: whether justifying factors must be accessible to the believer.
- Pragmatism: belief justified by practical success (Peirce, James, Dewey).
Scepticism
Sceptical challenges drive much epistemology:
- Pyrrhonian scepticism — Sextus Empiricus (Outlines of Pyrrhonism, c. 200 CE).
- Cartesian scepticism — the dreaming and the evil-demon hypotheses.
- Hume's problem of induction (1748).
- Kant's response — transcendental idealism limits but secures knowledge of phenomena.
- Moore's "Here is a hand" (1939) — common-sense response.
- Putnam's brain-in-a-vat (1981) — semantic-externalist response.
- Contextualism (Lewis, DeRose) — knowledge claims context-sensitive.
A priori vs. a posteriori; analytic vs. synthetic
These distinctions, central to modern epistemology:
| Distinction | Definition |
|---|---|
| A priori | Justified independently of experience |
| A posteriori | Justified by experience |
| Analytic | True by virtue of meaning ("all bachelors are unmarried") |
| Synthetic | Truth depends on more than meaning ("all bachelors are happy") |
| Kant's synthetic a priori | Substantive but knowable independently of experience (math, causality) |
| Quine's challenge | "Two Dogmas of Empiricism" (1951) attacks the analytic-synthetic distinction |
For CSS, structure metaphysics-and-epistemology answers around the central problems: substance, universals, mind-body, free will (metaphysics); JTB, Gettier (1963), sources of knowledge, scepticism (epistemology). Cite Plato's Theaetetus and Aristotle's Metaphysics as classical loci, Descartes' Meditations (1641) and Kant's Critique of Pure Reason (1781) as modern loci, and Gettier (1963) as the contemporary turning point.
Free will and determinism
A central metaphysical and ethical problem:
- Hard determinism: all events are causally determined; no free will (d'Holbach).
- Compatibilism: free will is consistent with determinism (Hume, Frankfurt).
- Libertarianism (metaphysical): free will requires indeterminism (Kane, van Inwagen).
- Hard incompatibilism: free will is incompatible with both determinism and indeterminism (Pereboom).
Modern neuroscience (Libet's experiments, 1980s) and physics (quantum indeterminacy) have re-entered the debate. In Islamic philosophy, the Mu'tazilites affirmed free will (qadar), the Ash'arites held human acts are God's creation but acquired (kasb).
Philosophy of religion
- Cosmological argument — Aquinas's Five Ways (1265–74); Kalam Cosmological Argument (al-Kindi, al-Ghazali; revived by William Lane Craig).
- Teleological argument — Paley's watchmaker (1802); Hume's critique in Dialogues (1779).
- Ontological argument — Anselm (Proslogion, 1078); Descartes (Meditation V); Plantinga's modal version (1974).
- Problem of evil — Epicurus's trilemma; Augustine's free-will defence; J.L. Mackie (1955); Plantinga's free-will defence (1974).
- Pragmatic — Pascal's Wager (1670), William James (Will to Believe, 1896).
- Reformed epistemology — Plantinga, Warranted Christian Belief (2000).
Contemporary debates in metaphysics and epistemology remain vigorous: modal metaphysics, social epistemology, virtue and value-based approaches to knowledge, the implications of cognitive science and AI for theories of mind.