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Metaphysics of Mind: Dualism, Physicalism and Functionalism
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AQA 7172 Paper 2 Section B: the mind–body problem, substance and property dualism (Descartes, Elisabeth, causal closure, Chalmers' zombies), behaviourism, type identity, eliminative materialism and functionalism — with 25-mark essay technique and full mark-scheme answers.
🎯 Learning Objectives
Explain the mind–body problem and define mental properties via qualia and intentionality (Spec 3.4.1).
Explain and evaluate Descartes' conceivability and divisibility arguments for substance dualism, and Elisabeth of Bohemia's interaction objection with the causal closure argument (Spec 3.4.2).
Explain and evaluate property dualism via Chalmers' zombie argument, including conceivability-vs-possibility and masking critiques (Spec 3.4.2).
Explain and evaluate logical behaviourism (Hempel, Ryle's category mistake) and its circularity, pretence and qualia critiques (Spec 3.4.3).
Explain and evaluate type identity theory (Place, Smart), the multiple realizability objection, and eliminative materialism (Churchlands) with the self-refutation critique (Spec 3.4.3).
Explain and evaluate functionalism (Putnam) via inverted qualia, philosophical zombies and absent qualia (Spec 3.4.4).
Use AQA command words correctly: pure AO1 explanation on 3/5/12-mark questions; argue with intent on 25-mark essays.
📋 Key Definitions and Core Concepts
Qualia: Intrinsic, subjective properties of experience — the felt hurtfulness of pain, the redness of red; 'what it is like' to undergo an experience, knowable only from the first person.
Intentionality: The 'aboutness' or directedness of mental states — beliefs, desires and fears are about things; Brentano's mark of the mental.
Substance dualism: Descartes' view that mind and body are distinct substances: the mind a thinking, unextended, indivisible thing; the body an extended, divisible, non-thinking one.
Property dualism: The view that mental properties are non-physical properties had by physical substances (brains): the mind supervenes on the body (Chalmers' naturalistic dualism).
Causal closure (of the physical): Every physical event that has a cause has a sufficient physical cause — so immaterial mental causes would violate the closure of physics or the mind is epiphenomenal.
Epiphenomenalism: The view that mental states are caused by physical states but have no causal power of their own — qualia are causally idle by-products of brain processes.
Philosophical zombie: A being physically and behaviourally identical to a human but lacking qualia — no inner experience, 'all is dark inside'.
Category mistake: Ryle: representing items as if they belonged to one logical category when they belong to another — treating 'mind' as a thing alongside the body, like the tourist asking where the University is after seeing all the colleges.
Logical (analytical) behaviourism: Mental-state statements are translatable without remainder into statements about behaviour (Hempel's hard version) or denote dispositions to behave (Ryle's soft version).
Type identity theory: Place and Smart: mental-state types are identical with brain-state types — a scientific identity like 'lightning is an electrical discharge', not a mere correlation.
Multiple realizability: One mental-state type can be realized by many different physical types (human, octopus, silicon) — Putnam's objection to type identity, built into functionalism.
Functionalism: Putnam: mental states are functional states, individuated by causal role — typical inputs, relations to other mental states and behavioural outputs — realizable in any medium.
The mind–body problem: qualia and intentionality (Spec 3.4.1)
The problem. Mental properties (belief, desire, pain, seeing red) seem unlike physical properties (mass, charge, neural firing): they are private, qualitative and about things. The mind–body problem asks how the two relate — is the mind a separate substance (dualism), a set of purely physical properties (physicalism), or states to be defined by what they do (functionalism)? Keep substance dualism (two substances) distinct from property dualism (one substance, two kinds of property): examiners report candidates conflating them.
Qualia. The intrinsic, subjective properties of experience — the felt hurtfulness of pain, the redness of red, 'what it is like' to see green (Nagel's bat). Qualia seem knowable only from the first person: no third-person description of neural firing appears to capture the feel itself. They power the whole anti-physicalist programme.
Intentionality. The 'aboutness' or directedness of mental states: a belief is about Paris, a fear about spiders. Brentano took intentionality as the mark of the mental — no purely physical item is intrinsically about anything (a picture is about Paris only through a mind's use: derived intentionality). Physicalists owe an account of how brain states acquire aboutness.
The tests. Every theory below must accommodate qualia, intentionality and mental causation (pain causes wincing) — measure each theory against all three.
Substance dualism and property dualism (Spec 3.4.2)
Substance dualism (Descartes). Mind and body are distinct substances: the mind a thinking, unextended, indivisible thing; the body an extended, divisible, non-thinking one. Conceivability argument (Meditations VI): (P1) I can clearly and distinctly conceive of myself as a thinking, non-extended thing; (P2) what I clearly and distinctly conceive as separate can be made to exist separately (by God); (C) mind and body are really distinct. Divisibility argument: (P1) every body is by nature divisible; (P2) the mind is not — amputate a limb and nothing is subtracted from the mind; (C) by Leibniz's law (identical things share all properties), mind is not body.
Elisabeth of Bohemia's interaction objection (1643 letters). How can an unextended, immaterial mind causally move an extended body? Causation between bodies requires contact and impulsion; a non-spatial thing has no surface to push with. Descartes' reply: the mind is 'intermingled' with the body — a real union, not mere concatenation — acting through the pineal gland; 'mind–body union' is a primitive notion grasped through everyday experience (hunger, pain), not by the pure intellect. Critics reply the defence concedes the point: if interaction needs the brain, the mind is not independent of it.
Causal closure. The modern version of Elisabeth: every physical event that has a cause has a sufficient physical cause. Immaterial mind-to-body causation would violate conservation of energy; so either mental causes are physical (physicalism) or the mind is an epiphenomenon — caused by the brain but causally idle, unable to move bodies or exercise free will. Dualists must either reject closure or accept epiphenomenalism.
Masking critique of conceivability. Conceivability is a poor guide to possibility: pre-chemistry one could conceive of water that is not H₂O, yet water is necessarily H₂O; conceiving mind as separable may mask an identity. Descartes' reply: he claims complete (clear and distinct) understanding of the mind, not partial — only partial conceivability is unreliable.
Property dualism (Chalmers). Mental properties are non-physical properties of physical substances (brains): the mind supervenes on the body. Zombie argument: philosophical zombies are physically and behaviourally identical to us but lack qualia — 'all is dark inside'. Zombies are conceivable; what is conceivable is metaphysically possible; if zombies are possible, physical facts do not fix conscious facts; so physicalism is false. Critiques: (1) conceivability is not possibility (Kripke's necessary a posteriori truths; Dennett: a behaviourally identical being making all our consciousness reports would thereby be conscious — zombies are incoherent); (2) the physicalist denies premise 2: that zombies are impossible is physicalism, so the argument begs the question; (3) interaction problems return — Chalmers' psychophysical laws leave qualia causally idle. Appeal: property dualism explains qualia and leaves science intact, but inherits the interaction problem.
Physicalism: behaviourism, type identity and eliminative materialism (Spec 3.4.3)
Logical (analytical) behaviourism. Mental statements translate without remainder into statements about behaviour. Hempel (hard): 'X is in pain' means X winces, groans, says 'ouch' and reports pain when asked. Ryle (soft): mental concepts denote dispositions to behave (if burned, X would flinch), and Descartes' 'ghost in the machine' rests on a category mistake: treating the mind as one more thing alongside the body when mental vocabulary describes ways bodies behave — like the tourist who, shown the colleges, libraries and labs, asks 'but where is the University?'. Critiques: (1) circularity: dispositions must be defined using other mental terms (desire, belief); (2) perfect actors and super-spartans: behaviourally identical subjects can differ — real pain vs flawless pretence, or pain felt while showing nothing — so behaviour does not exhaust the mental; (3) qualia: behaviourism cannot state what pain feels like, missing the qualitative character of experience.
Type identity theory (Place, Smart). Mental-state types are identical with brain-state types — a scientific identity like 'lightning is an electrical discharge' (Place), not a mere correlation. Strengths: parsimony (one substance); interaction solved (pain is C-fibre firing, so mental causation is trivial); science-friendly. Multiple realizability (Putnam): the same mental type is realized by different physical types — pain in humans (C-fibres), octopuses (different wiring), perhaps silicon; by Leibniz's law, pain cannot be identical with any single brain-state type. Responses: token identity (each pain token is some brain state) or species-specific identities; counter: reduction then covers only humans and will not generalize to artificial minds.
Eliminative materialism (the Churchlands). Folk psychology (belief–desire explanation) is a radically false empirical theory whose categories — belief, desire, pain — will be eliminated and replaced by mature neuroscience, as phlogiston and caloric fluid were. Evidence: folk psychology fails on sleep, intelligence, memory and mental illness, and has stagnated for 25 centuries. Critiques: (1) self-refutation: 'folk psychology is false' is asserted as a belief, presupposing what it denies; the Churchlands reply that this begs the question — like a phlogiston theorist insisting 'but I believe in phlogiston'; (2) folk psychology is successful: it predicts everyday behaviour superbly, unlike phlogiston; reply: its successes are shallow — it fails precisely where understanding matters.
Functionalism and the qualia objections (Spec 3.4.4) + exam technique
Functionalism (Putnam). Mental states are functional states: individuated by causal role — typical causes (inputs: bodily damage), relations to other mental states (belief that something is wrong; desire to escape) and typical effects (outputs: wincing, saying 'ouch'). A state is pain in virtue of playing the pain role, whatever its material — brains, silicon, or (Putnam's original) the states of a Turing machine. Strengths: builds in multiple realizability (answers type identity's main objection); keeps inner states distinct from behaviour (answers behaviourism's circularity and pretence problems); compatible with scientific psychology.
Inverted qualia. Two subjects functionally identical — same inputs, outputs and organization — yet their colour experiences qualitatively inverted. If possible, functional role does not fix qualitative character, so functionalism misses qualia. Functional response (Chalmers' fading/dancing qualia): invert qualia gradually while holding functional organization fixed — the subject could not notice, yet conscious experience cannot systematically fade or flicker without functional change; so inverted qualia are impossible. Counter: the argument assumes phenomenal change requires functional change — exactly what the objection denies.
Absent qualia (Block's China brain). A billion Chinese citizens, each playing one 'neuron' and linked by two-way radio, implement the functional organization of a human brain. The functionalist must attribute pain to the nation; intuitively there is no unified conscious subject — so functional organization does not suffice for consciousness. Responses: intuitions about alien systems are unreliable; functionalism need not claim the system is conscious exactly as we are. Zombies: a functional duplicate of you with no inner life is conceivable — functional organization leaves out qualia (with the conceivability caveats from dualism).
Exam technique: AQA 7172 Paper 2 Section B (click to expand)
Paper 2: Section A Metaphysics of God, Section B Metaphysics of mind — five questions per section worth 3, 5, 5, 12 and 25 marks; all AO1 except the 25-marker (5 AO1 + 20 AO2, 'Evaluate this claim').
3/5/12-markers: explanation only — define terms, set out the claim, argument or objection, illustrate. Evaluation is redundant and loses marks.
25-marker top band (21–25): define key terms, state a thesis, develop one or two debates in depth (crucial arguments vs less crucial), give weak then strong responses to objections, finish with a consistent conclusion and no new ideas.
Highest-yield 25-marker debates: zombies vs physicalism/functionalism; interaction problem vs dualism; multiple realizability vs type identity; inverted qualia vs functionalism.
💡 Worked Example
Exam-style: 'Philosophical zombies are conceivable, so physicalism is false.' Evaluate this claim. (25 marks)
Mark-scheme logic: AO1 required: define physicalism (all facts, including mental facts, are fixed by physical facts); define philosophical zombies (physically and behaviourally identical to us, no qualia); set out Chalmers' argument: zombies are conceivable; what is conceivable is metaphysically possible; if zombies are possible, physical facts do not determine conscious facts; so physicalism is false. AO2 required: argue with intent, e.g. FOR the claim — (1) qualia are knowable only from the first person (Nagel), so no physical description fixes the feel of experience; (2) zombie scenarios are coherently describable: a world physically identical yet qualitatively empty involves no contradiction. Consider the strongest objection AGAINST: conceivability is not a guide to possibility — Kripke's necessary a posteriori identities (water = H₂O: conceivable without H₂O, yet impossible), and Dennett's charge that zombies are incoherent: a behaviourally identical being making all our consciousness reports would thereby have whatever makes consciousness; respond: Chalmers distinguishes ideal (primary) conceivability from mere imagery and argues ideal conceivability entails possibility; counter-response: that entailment is exactly what physicalists deny — 'zombies are possible' is just physicalism's negation restated, so the argument risks begging the question. Weigh up (e.g. the argument survives as a challenge to reductive physicalism, but functionalist/non-reductive physicalism can resist it) and conclude consistently.
❓ Practice Questions & Mark Schemes
Explain the difference between mental and physical properties. (5 marks)
Answer: AO1 only — no evaluation. Physical properties (mass, shape, charge, neural firing) are public, objective and measurable by third-person science. Mental properties (belief, desire, pain, seeing red) are private (only the subject has direct access), qualitative (there is something it is like to have them — qualia) and intentional (they are about things: a belief is about Paris). Intentionality marks the mental (Brentano): no purely physical item is intrinsically about anything — a picture is about Paris only through a mind's use. Illustrate: C-fibre firing is a physical state detectable by scanners; the hurtfulness of pain is a mental property accessible only to the sufferer.
Explain Descartes' divisibility argument for substance dualism. (5 marks)
Answer: AO1 only. (P1) Every body is by its nature divisible — any extended thing can be cut into parts. (P2) The mind is not divisible: it has no spatial parts; when a foot or arm is amputated, nothing is taken away from the mind, and its faculties (understanding, will) form one indivisible thing. (C) By Leibniz's law — if x has a property y lacks, x is not identical with y — the mind is not identical with the body; they are distinct substances. Hence substance dualism.
Explain Elisabeth of Bohemia's objection to substance dualism and Descartes' response. (12 marks)
Answer: AO1 only. Set out substance dualism: mind (thinking, unextended, indivisible) and body (extended, divisible) are distinct substances. Elisabeth's objection (1643 letters): causation between bodies requires contact and impulsion — a push needs a surface and a transfer of motion; an unextended, immaterial mind has no surface or location, so it is unintelligible how it could move the body (or be affected by it). Explain Descartes' responses: (1) the mind is 'intermingled' with the body — a real union, not mere concatenation, so interaction is not push-and-contact; (2) interaction operates through the pineal gland; (3) 'mind–body union' is a primitive notion grasped through everyday experience (hunger, pain), not through the pure intellect, so Elisabeth's demand for a mechanical model misapplies the wrong primitive notion. Conclusion: Descartes concedes interaction is special rather than mechanical; critics argue that if interaction runs through the brain, the mind is not independent of the body — which points to the causal closure objection.
Explain the multiple realizability objection to type identity theory. (12 marks)
Answer: AO1 only. Define type identity theory (Place, Smart): mental-state types are identical with brain-state types — pain is C-fibre firing — a scientific identity like 'lightning is an electrical discharge'. Explain the objection (Putnam): the same mental type can be realized by different physical types — pain in humans (C-fibres), octopuses (different neural wiring), reptiles, perhaps artificial systems; if pain can exist without C-fibre firing, then by Leibniz's law pain cannot be identical with C-fibre firing; so no mental type is identical with any single brain-state type, and type identity is false. State the responses: (1) token identity — each individual pain is identical with some brain state, though there is no one type; (2) species-specific identities — human pain is one brain state, octopus pain another. State the counter: then the theory covers only humans, fails to generalize to artificial minds, and the 'science of the mind' becomes piecemeal — which is why functionalism (states defined by causal role, realizable in any medium) was developed.
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