Physicalist theories — AQA A-Level Philosophy

Physicalism is the view that everything is either itself physical or supervenes upon the physical. Supervenience means that if two situations are identical in every physical respect, they cannot differ in any other respect: there can be no non-physical difference without a physical difference. The statement's scope is deliberately broad, covering properties (such as being in pain), events (such as a thought occurring), objects (such as a brain) and any substance or substances that exist. So physicalism denies that there is any separate mental substance, while still allowing that mental properties can be real provided they depend entirely on physical facts. A correct answer distinguishes physicalism from substance dualism and from the weaker claim that everything simply happens to be physical without any dependence relation.

Hard behaviourism is the strongest physicalist reading of the mental. Its claim is semantic: every proposition that appears to talk about a mental state can be translated, with no change of meaning, into propositions that speak only the language of physics — bodily states and movements. So 'Anna is in pain' is not merely caused by, or correlated with, her body; it means the same as a statement about her bodily condition and behaviour. Hempel's logical-analysis approach treats psychological sentences as reducible to physical ones, so the mental vocabulary is retained only as shorthand. The test of the theory is whether the translation really preserves meaning: if the physical paraphrase loses something the mental sentence said, hard behaviourism fails. Contrast soft behaviourism, which analyses mental talk into behavioural dispositions rather than into the language of physics.

Soft behaviourism analyses mental-state talk as talk about behavioural dispositions, expressed in ordinary language rather than the language of physics. Gilbert Ryle is the named proponent. A disposition is a tendency to behave in certain ways under certain conditions: to say someone is brave is to say they would tend to act in particular ways when facing danger, not to report a hidden inner object. Crucially, the analysis stays in everyday vocabulary such as 'would do X if Y', so it does not require translation into physics. In an MCQ, separate soft behaviourism from hard behaviourism (Hempel's meaning-preserving reduction to physics language) and from the idea that dispositions are mere reflexes: dispositions are conditional tendencies, not guaranteed occurrences.

Philosophical behaviourism holds that to have a mental state just is to be disposed to behave in certain ways, so talk of minds is analysable into talk of behavioural dispositions. Dualist arguments can be turned against this claim. The conceivability and knowledge arguments press that mental states could occur without the corresponding behaviour, or be known without knowing dispositions, which behaviourism cannot allow. The argument from introspection presses that we are directly aware of inner experiences, not merely of tendencies to act. Learners should reconstruct each dualist argument in its strongest form, state the behaviourist premise it targets, and then assess whether the behaviourist can reply, for example by widening dispositions to include hypothetical and verbal behaviour.

This topic examines whether mental states can be distinguished from behaviour, using Hilary Putnam's thought experiments. The Super-Spartans are a community who suppress all outward signs of pain yet, Putnam suggests, still feel pain, so pain cannot be identical with pain behaviour or the disposition to display it. Perfect actors are people who convincingly display the behaviour associated with a mental state without actually having it, so behaviour is not sufficient for the state either. Together the cases press that mental states are distinct from behaviour: neither necessary nor sufficient for it. Learners should set out each case precisely, explain what it is meant to show about the behaviourist analysis, and assess responses, for example that behaviourism concerns dispositions including suppressed ones, or that the cases beg the question.

Behaviourism defines a mental state as a disposition to behave in certain ways. Two problems arise. (a) Circularity: to specify the behaviour we must already refer to the mental state. A disposition to seek water is only 'thirsty' behaviour if we assume the desire for water; describing the outward movements without the mental vocabulary becomes impossible or question-begging, so the definition moves in a circle. (b) Multiple realisability: the same mental state can be realised by very different behaviours. Fear might produce fleeing, freezing or a calm facade; pain might produce crying or stoicism. If one state maps onto indefinitely many behaviours, no finite behavioural definition captures it.

The asymmetry concerns how we know our own mental states compared with others'. First-person self-knowledge is typically direct and non-inferential: you know you are in pain without observing your behaviour or gathering evidence. Knowledge of other minds is indirect: you infer their states from behaviour, testimony, context and analogy, and you can be wrong. This asymmetry is used both to support and to challenge physicalist theories. It can seem to favour the idea of a private inner access that behaviourism struggles to accommodate, yet physicalists may reply that the difference is one of access route, not of underlying nature. A good answer identifies the two directions of knowledge, explains the evidential difference, and connects it to the debate about physicalism.

Type identity theory holds that every type of mental state just is a type of brain state: pain is identical with a particular neural state, not merely caused by it. This is ontological reduction because it claims that what exists is one kind of thing, described in two vocabularies. Crucially, the identity is not analytic: 'mental state' and 'brain state' do not mean the same, so the claim is a substantive, empirically discoverable identity like 'water is H₂O'. A good test question asks you to distinguish this from behaviourism (which analyses mental talk away) and from analytic reduction (which treats the identity as true by meaning). Identify the claim that mental states are identical with brain states yet the terms differ in meaning.

This topic asks you to take dualist arguments and use them as objections to type identity theory, then assess how well the theory replies. The key dualist lines are: the conceivability and possibility of mind without body (substance dualism); the 'knowledge argument' about knowing all physical facts yet not knowing what an experience is like (property dualism); and the apparent distinctness of mental and physical properties. Applied to type identity, these argue that if mental states were identical with brain states, such scenarios would be impossible or the identity would be knowable a priori, which it is not. Assess by weighing replies: identity theorists say conceivability does not entail possibility, and that identities like water/H₂O are discovered a posteriori. Build a structured argument, use examples, and evaluate rather than merely list.

Type identity theory claims each mental state type is identical with a physical (typically neural) state type, so pain is one kind of brain state. Multiple realisability attacks the type identity: the same mental type, such as pain, appears in humans, octopuses and hypothetical silicon systems whose physical realisations differ. If one mental type can be realised by many distinct physical types, no single physical type is identical with it, so the proposed type identities fail. A learner should set out the argument: pain is realised in many different physical systems; if pain were identical with one physical type, it could occur only where that type occurs; but pain occurs across diverse systems; therefore pain is not identical with any one physical type.

Eliminative materialism holds that some or all of the states posited by common-sense or folk psychology, such as beliefs, desires and pains as inner entities, do not really exist. Folk psychology is the everyday framework that explains behaviour by attributing such states, and eliminativists argue it is a radically mistaken theory that mature neuroscience may replace rather than reduce. Patricia Churchland and Paul Churchland defend this view. A learner should distinguish the strong claim that all folk-psychological states are illusory from the weaker claim that some are, and recognise that eliminativism differs from identity theory, which keeps the mental states and identifies them with physical ones. The position predicts that as neuroscience advances, talk of beliefs and desires may be abandoned like earlier discarded posits such as caloric or phlogiston.

This claim is a methodological starting point used against physicalist reductions of mind. It says that whatever else is uncertain, you cannot seriously doubt that you are now having some experience, thought or sensation. So any theory that denies the mental, or redescribes it as nothing but physical, must explain away something we seem to know more directly than we know brain states. The argument form is: mental states are known with first-person certainty; physical states are known by inference and observation; therefore the certainty of the mental is a constraint any theory must meet. Teach learners to separate the epistemic point (how we know) from the metaphysical point (what exists). Certainty about experience does not by itself prove dualism, but it sets a burden of proof on the physicalist.

Folk-psychology is the everyday framework of beliefs, desires, intentions and emotions we use to make sense of people. This claim is an inference-to-the-best-explanation argument: because folk-psychology predicts and explains behaviour well, it is rational to treat its posits as real rather than as useful fictions. The structure is: we observe reliable behavioural prediction; the best explanation of that success is that mental states exist and cause behaviour; therefore folk-psychology is the best hypothesis. Learners should see how this supports realism about the mental against eliminativism, which says folk-psychology is a false theory to be replaced. Evaluate the strength: is predictive success unique to folk-psychology, or could neuroscience or behaviourist descriptions do as well? Note the claim concerns explanatory power, not proof.

Eliminative materialism holds that everyday mental talk — beliefs, desires, sensations — is a false folk theory that mature neuroscience will replace rather than reduce. The self-refutation charge targets the act of stating this: if the theory is true, there are no beliefs, so no one can believe it, assert it or be justified in accepting it. A candidate answer should reconstruct the argument in order: the eliminativist asserts a proposition; assertion presupposes belief; eliminativism denies beliefs exist; therefore the theory undercuts its own utterance. Learners should also weigh replies, such as distinguishing the content of a claim from the mental act of holding it, or restricting elimination to specific posits rather than all intentional states, and judge whether these rescue the theory.