3.4.4 - Functionalism and qualia objections

The Functionalist Problem

The problem for functionalism begins with a simple thought: mental states seem to do work in a person's life. Pain is normally caused by bodily damage, interacts with beliefs and desires, and tends to produce avoidance, distress, reports of pain, and protective action. Belief that it is raining is normally caused by perception or testimony, combines with desires, and helps explain why someone picks up an umbrella.

Functionalism says that this role is what makes a mental state the kind of mental state it is. A mental state is not identified by the material that realises it, such as a specific human brain state, nor merely by outward behaviour. It is identified by its causal place in a system.

Qualia, the qualitative feel of experience such as what pain or seeing red is like from the inside, are where the main objections press hardest.

Functionalism is initially attractive because it seems to explain why mental states matter. A state counts as pain because of what it is set up to do in the whole mental economy: receive bodily-damage input, interact with beliefs and desires, guide attention, produce avoidance, and so on. This also lets functionalism avoid a narrow human-brain requirement. If an octopus, alien or artificial system has a state playing the pain role, functionalism can at least make sense of attributing pain to it.

The pressure is immediate. Functionalism gains flexibility by describing mental states in terms of relations and roles. But qualia objections ask whether the feel of experience can be captured by any such relational pattern. Perhaps functionalism explains what pain does without explaining how pain feels.

Functional Roles

A functional role is a causal role. It links three broad elements:

Putnam's central move in The Nature of Mental States is to treat pain as a functional state of the whole organism rather than as one particular brain state or as a mere behavioural disposition. The point is not that every pain must produce identical behaviour. Pain may be hidden, suppressed, misunderstood, or overridden by stronger desires. The point is that pain belongs to a network of typical causal relations.

Functionalism is therefore different from philosophical behaviourism. Behaviourism tries to analyse mental-state talk in terms of behaviour or behavioural dispositions. Functionalism includes internal states and their relations to one another. A person can be in pain while keeping still because the relevant internal role may still be present: the pain is caused by damage, produces distress and a desire for relief, and would normally lead to protective behaviour if not suppressed.

The basic functionalist proposal can be reconstructed like this:

1. P1: A mental state type is individuated by the causal role it plays in a system.
2. P2: Pain plays a role involving typical bodily inputs, relations to beliefs and desires, and behavioural outputs.
3. P3: A system is in pain when one of its internal states plays that pain role.
4. Therefore, C: Pain can be characterised as a functional state rather than as a specific brain state or mere behaviour.

Hidden assumption: The relevant causal role is sufficient for the mental state, not merely evidence for it.
Inference type: abductive and conceptual; it argues that functional role gives the best analysis of mental-state kinds.
Main pressure point: whether qualitative feel is fixed by role.

This is not meant to be a finished psychology of pain. It is a schema. A complete functionalist theory would need to specify the role carefully enough to avoid counting too many things as mental, while keeping it general enough to include non-human minds. That balancing act becomes crucial when Block's objection appears later.

Multiple Realisation

This is easiest to see through ordinary functional objects. A mousetrap can be made of wood, metal or plastic if it performs the relevant function. What makes it a mousetrap is not one exact material composition but its role in catching mice. Functionalism applies the same style of thought to mental states. If pain is a role, then it may be realised by human neural states, animal nervous systems, or perhaps artificial systems, so long as the right causal organisation is present.

This is an objection to mind-brain type identity theory. Type identity theory says each mental state type is identical with a brain state type. Functionalism says that is too narrow. If pain in humans is realised by one neural kind, pain in an octopus or alien might be realised by a very different physical kind. There may be no single physical-chemical type common to every possible pain bearer.

Reconstruction of the multiple realisation argument:

1. P1: If type identity theory is true, each mental state type is identical with one physical state type.
2. P2: The same mental state type, such as pain, can be realised by different physical state types in different systems.
3. P3: If one mental state type can be realised by different physical state types, it is not identical with any one of those physical types.
4. Therefore, C1: Type identity theory is false or at least too restrictive.
5. Therefore, C2: Functionalism is a better candidate because it identifies mental states by role rather than by one physical realiser.

Hidden assumption: The different creatures or systems really share the same mental state type, rather than only similar states.
Inference type: deductive against strict type identity if P2 is granted; abductive in favour of functionalism.
Main pressure point: P2, because critics can question how same the state must be across different species or systems.

The argument is powerful because it makes functionalism look less chauvinistic than type identity theory. It does not restrict mentality to creatures with human-like brains. It also fits scientific explanation: psychologists often explain behaviour by beliefs, desires, pain, perception and memory without first specifying the exact neural realiser in every species.

But the argument also creates a danger. If functional roles are described too generally, functionalism may count too many systems as having mental states. If roles are described too specifically, functionalism may lose the flexibility that made multiple realisation attractive. The qualia objections exploit this tension.

Inverted Qualia

The inverted qualia objection imagines a functional duplicate whose qualitative experiences are systematically different. For example, two people may have the same colour-discrimination abilities, use colour words in the same way, make the same choices, and have the same internal functional transitions, while the experience one has when seeing red is qualitatively like the experience the other has when seeing green.

The scenario is not about ordinary colour-blindness or different language use. Those would produce functional differences. The imagined case is sharper: all functional facts remain the same, but the qualitative feel differs.

Structure of the thought experiment:

Reconstruction of the objection:

1. P1: If functionalism is true, functional duplicates must have the same mental states, including the same qualia.
2. P2: It is possible for functional duplicates to have different qualia, as in inverted colour experience.
3. Therefore, C: Functionalism is false, because functional role does not fix qualitative character.

Hidden assumption: Inverted qualia with no functional difference is genuinely possible, not merely imaginable in a loose way.
Inference type: conceptual counterexample.
Main pressure point: P2, because the functionalist can deny that real qualitative inversion would leave all roles unchanged.

Why the objection matters: it targets sufficiency. It does not say functional role is irrelevant. It says functional role may leave something out. If a red-experience role can be filled by different qualia, then the role is not enough to identify the qualitative mental state.

Functionalist replies:

The inverted qualia objection is strongest against the claim that function alone transparently explains phenomenal character. It is weaker if functionalism only needs to provide the best overall theory and can argue that alleged inversions are under-described or incoherent.

Block's China Thought Experiment

Block's China thought experiment is an absent qualia objection. Instead of imagining the wrong qualia, it imagines no mentality or no qualia despite the right functional organisation.

The basic scenario is lean. A huge population is organised so that each person performs the role of a small part of a human functional system. They communicate by radio, use visible signals or instructions, and are connected to an artificial body. For a limited period, the whole system mirrors the functional organisation of a human being.

Block's challenge is that the system may be functionally equivalent to a person but still seem not to have a unified conscious mental life. Individual citizens have their own experiences, but the population-plus-body system does not obviously feel pain or see red as a whole.

Reconstruction of the China objection:

1. P1: If functionalism is true, any system with the right functional organisation has the relevant mental states and qualia.
2. P2: The China-body system could have the right functional organisation.
3. P3: The China-body system would not have genuine mentality or qualia as a whole.
4. Therefore, C: Functional organisation is not sufficient for mentality or qualia.

Hidden assumption: Our judgement that the China-body system lacks mentality is reliable.
Inference type: conceptual counterexample using a thought experiment.
Main pressure point: P3, because the functionalist can say the intuition is driven by unfamiliar scale and composition.