Metaphysics of mind - Functionalism

What is functionalism a descendent of?

Logical behaviourism.

What is the difference between logical behaviourism and functionalism?

Instead of talking of dispositions to behave in certain ways in certain circumstances, functionalism talks of dispositions to behave and to have other mental states, given sensory inputs and other mental states.

Why does functionalism explicitly recognise that mental states cannot be understood just in terms of behaviour?

First, mental states often cause other mental states, e.g. pain normally causes the belief that one is in pain. Second, what behaviour a mental state will cause depends on other mental states. So the definition of one mental state will have to mention other mental states (the issue of circularity).

What is an example of a functional definition?

A kidney can be understood as performing a particular function. This can be understood in terms of inputs and outputs, blood passes into the kidney and urine and filtered blood passes out. Therefore a kidney can be said to be defined as something that serves this function. An important point to mention is that the method by which the kidney achieves its task is not essential to its functioning role.

What is an example of the method by which something achieves its task not being essential to its functioning role?

The internal design of an artificial / synthetic kidney is different to that of an organic kidney. It is larger, made of different materials and filters using a different method yet this does not stop us from referring to this as a type of kidney.

Why is determining the function of something and being clear about function very important?

The same structure can have more than one function.

What is an example of the same structure having more than one function?

If a box is being used as a table, it is functionally a table; it serves the purpose of a table. However if at some point we stop using the box as a table and begin to use it to store items then it is now functionally a box and not a table despite the fact that the structure of the box has not changed.

What does functionalism claim about substances?

We can understand the mind and mental states without making any claims about what substances exist.

How does functionalism define the mind and mental states?

Not in virtue of their physical nature, but in terms of the function they perform. It defines mental states as inner states that have a certain function, they interact with other mental states in a particular way and they have particular causal relations to various sensory inputs and behavioural outputs.

What is a basic definition of a mental state for functionalism?

Something that takes sensory input, produces behavioural output, and interacts with other mental states.

What is an example of a functionalist definition of mental states?

Being stabbed with a knife (sensory input) → inner state of pain (M.S.) → Shouting out, eyes watering, screwing up face (behavioural output)

What does functionalism reduce mental properties to?

Functional properties

What is multiple realisability for functionalism?

There may be lots of different states, e.g. different brain states, that have this functional property. This can vary from one species to another. But as long as some state of the creature has the function that defines pain - given certain inputs, it causes certain outputs - then the creature is in pain.

What is an example of mental states interacting?

Seeing a bomb → belief that the bomb will explode + desire to stay alive → Running away

What is it to have a belief, desire or emotion for functionalism?

To have something within us which causes certain behaviours. It is also to have something that may causally interact with other beliefs, ideas, emotions etc. Functionalism defines mental states in terms of relations between inputs, outputs and other mental states, it also accepts that they are inner states.

How does causal role functionalism understand the relationship between inputs, the state, and outputs?

Causally. Many things can be understood in terms of fulfilling a causal functional role (e.g. being an eye, being a poison, being a mousetrap). The same is true of mental states (e.g. what it is to be a belief, desire, pain, etc.)

How does functionalism analyse mental states?

In terms of what they do, not in terms of the nature of the substance that realises those mental states.

Is functionalism logically compatible with both substance / property dualism and physicalism?

Yes, mental states could be realised by physical states or they could be realised by states in a distinct mental substance.

What are most functionalists?

Physicalists

What are functional properties?

Functional properties occur throughout science (e.g. being an eye). They are not themselves physical properties, because there are lots of different ways in which eyes can be constituted physically. However, functional properties are properties which are realised by physical properties operating in causal relationships. They are not a completely new kind of property.

What is computational functionalism?

Mental states are machine table states. For each possible input, they produce a particular output. Described by a ‘machine table’ - a complete list of descriptions of the form ‘if the machine is in state S1 and receives input I1, then it produces output O1 and goes into state S2’. For every possible input + state combination, an output is assigned.

What does functionalism claim that something must have in order to have functional states?

Whether it understands functions in terms of causal roles or in terms of machine tables, it must have a complex internal organisation.

If a functional state is a state with a particular causal role, what must that causal role be filled by?

An inner state of whatever possesses the function.

What is an example of multiple realisability for causal role functionalism?

To fulfil its function, an eye has to have parts that enable it to convert light waves into nerve firings. Different types of eye have different parts, different structures, but they must all have some structure or they couldn’t enable the creature to see.

What is an example of multiple realisability for computational (machine table) functionalism?

A machine that implements a machine table must have a number of distinct physical states that it moves between in response to various inputs and that produce distinct outputs. Again, we need not know what these inner states are, what they are made of, or exactly what mechanisms make them work as they do, but there must be inner states that match each of the functions described by the machine table.

Does the nature of inner states matter as long as it realises the function?

No

Could things without brains have mental states for functionalism?

For something - whether it is a machine or an anaimal or a human being - to have mental states, it must have a complex organisation of inner states that work in ways to fulfil the necessary functional roles. These inner states could be states of the brain, but they don’t have to be. Things without brains could have mental states, as long as the relevant functions are performed by some part of them.

Do functionalists argue that each mental property is also a functional property?

Yes, there may be lots of different states that have this functional property The states may also vary from one species to another. But as long as some state of the creature has the function that defines the mental state - given certain inputs, it causes certain outputs - then the creature has the mental state.

What does Putnam argue about mental properties not being identical to physical properties?

Mental properties are not identical to physical properties because the same mental property can eb related to or supervene on different physical properties.

What is an example of mental properties not being identical to physical properties?

The brain states that relate to pain may be different in different species, in humans and birds for example, but pain is the same mental state.

What is the argument from multiple realisability against functionalism?

There are creatures who, when they are in pain, have different physical properties from us when we are in pain. Therefore, ‘being in pain’ cannot be exactly the same thing as having a particular physical property.

Do functional properties in general supervene on physical properties?

Yes

Why is it the case that if qualia exists, functionalism cannot be true of phenomenal consciousness?

There are some MS that can’t be understood functionally. There is more to pain than just what causes it and what it causes.

What is the functionalism and qualia argument?

P1. Qualia, by definition, are intrinsic, non-representational properties of conscious mental states.

P2. Intrinsic, non-representational properties cannot, by definition, be completely analysed in terms of their causal roles.

C1. Therefore, if qualia exist, some mental properties cannot be analysed in terms of their causal roles.

P3. Functionalism claims that all mental properties are functional properties which can be completely analysed in terms of their causal roles.

C2. Therefore, if qualia exist, functionalism is false.

P4. Qualia exist.

C3. Therefore, functionalism is false.

What is the possibility of a functional duplicate with different qualia objection to functionalism (inverted qualia)?

We can show that phenomenal properties cannot be understood just in terms of their functions if we can show that it is possible for two people to have states with identical functions but different phenomenal properties. Functionally we are identical, and yet we have different experiences / qualia.

What is an example of inverted qualia?

Suppose that you and I are looking at ripe tomatoes and fresh grass. Because we have grown up in the same linguistic community, we have learned to use the word ‘red’ to describe the tomatoes and ‘green’ to describe the grass. So we both say that the tomatoes are red, the grass is green. But the particular way that tomatoes seem to me is the way that grass looks to you, and vice versa. ‘The way the grass looks to you’ and ‘the way the grass looks to me’ are functionally identical, both are caused by the same inputs (grass) and cause the same outputs (saying ‘grass is green’). But they are not identical in terms of their intrinsic properties. They refer to different qualia.

Does it matter that we might not know whether inverted qualia actually exists or not?

It is irrelevant. The objection is that inverted qualia are possible. If functionalism were true, inverted qualia would be impossible. So functionalism is false.

What is the inverted qualia argument put simply?

MS = Functional State.

Duplicated FS but different MS

Therefore, FS cannot = MS

What is the inverted qualia objection in SLF?

P1. Functionalism claims mental states are functional states.

P2. I can conceive of a being that has identical functional states to me but has different qualia.

C1. If this is true then qualia cannot be a functional state.

C2. If this is true then not all mental states can be understood only in terms of functional states.

C3. Therefore functionalism is false.

What does Patricia Churchland say about the inverted qualia argument?

The two people are not functionally identical. There are going to be small, but very important differences, because the causal relations of phenomenal properties are very complex. Also, we have no good reason to think that qualia can be inverted in the way the thought experiment describes. We have no evidence from neuroscience that the brain functioning gives rise to different conscious experiences in different people. Also, as an empirical hypothesis, it is poor, since it proposes that there could be empirical differences (in our conscious experience) that are undetectable, since they make no functional difference. Science does not proceed by supposing undetectable facts. So if the inverted qualia objection were empiricial, then it is either false or bad science.

Why does Patricia Churchland claim that the inverted qualia argument is like other arguments from conceivability?

In saying that you and I could function in exactly the same way, but have different qualia, ‘could’ just means ‘it is conceivable’. So the argument is like other arguments from conceivability, and faces the same objections as the other arguments. We can question whether it is conceivable, whether, even if it is conceivable, it is possible, and whether its possibility tells us anything about whether there actually are qualia.

Why does Patricia Churchland claim that the inverted qualia thought experiment is much too simple?

First, every colour that we can discriminate has unique similarity and dissimilarity relations to all surrounding colours. For instance, red is more similar to orange than green is, while green is more similar to blue than red is. So we can’t simply switch red and green without messing this up. If you and I saw red and green ‘switched’, then we wouldn’t agree on whether red was more similar to orange or blue. And this is a functional difference.

What is a response to Patricia Churchland’s claim that the inverted qualia thought experiment is much too simple?

To change the thought experiment - it is not just red and green that are inverted, but the whole spectrum. This could keep all similarity relations as well.

What is the issue with changing the inverted qualia thought experiment so that the whole spectrum is inverted?

Human beings can make much finer discriminations in green, yellow and orange than in blue. If we inverted everything, this would be apparent from behaviour, as whoever sees the inverted colours would be able to make finer discriminations among blue than the rest of us can, and fewer discriminations in green, yellow and orange. And so it is empirically impossible for someone to have inverted qualia without functional differences.

How does Block frame his argument?

In terms of machine-table functionalism.

Why does Block pick China for his thought experiment?

The population of China is 1 billion, which may be enough to fulfil the functions that comprise your mental states.

What is Ned Block’s China thought experiment - the possibility of a functional duplicate with no qualia?

Suppose we have a complete functional description of your mental states. For each and every one of your mental states, we have an input-output analysis, giving us a machine table for your mind. Now imagine that a human body, like yours, is connected up via its sensory and motor nerves not to a brain, but through electronic transmitters, to the whole population of China. The Chinese people are linked up to each other by two-way radios, and some of these are linked up to the input and output nerves of the body. Then, for a short time, the Chinese population realises the same machine table that describes the functions of your mental states.

Why is Block’s thought experiment a problem for functionalism?

According to functionalism, this should create a mind. But even if we could accept that this set-up could have intentional mental states such as beliefs or thoughts, it is especially difficult to believe that there would be a ‘Chinese consciousness’. If the chinese system replicated the functioning of my brain when I feel pain, would something be in pain? What? Is there something it is like to be this system? The objection is that the Chinese system, although it duplicates your functioning, can’t duplicate your mind, because some mental states are qualia, and the system can’t have qualia because they are not functional states.

What is the absent qualia objection in SLF?

P1. Functionalism claims that all mental states can be understood in terms of sensory inputs and behavioural outputs.

P2. In Block’s China mind experiment he poses a scenario where we would map every one of your mental states, producing an input-output analysis, giving us a machine table for your mind.

P3. For a time the Chinese population realises the same machine table that describes the functions of your mental states, using two way radios, toggle switches and connections to the sensory and motor nerves of a human body.

P4. Block argues that it would be absurd to suggest that there is anything experiencing the qualia of MS is this system. E.g. when it replicates your pain the system would not be in pain.

C1. Therefore we have a functional duplicate but without qualia.

C2. Therefore not all MS are functional states.

C3. Therefore functionalism is false.

What is the first possible response to Block’s China mind experiment?

The Chinese system won’t be functionally identical to you. For instance, it could be disrupted by things that your mind isn’t disrupted by e.g. the radios running out of batteries or the system being disrupted by bad weather.

What is an objection to the response to Block’s China mind experiment that the Chinese system won’t be functionally identical to you?

True, but irrelevant. First, although this could happen, if it doesn’t, then we have functional duplication, and the functionalist must say that the Chinese system is conscious. Second, these disruptions don’t count as inputs or outputs, any more than having a brain tumour counts as an ‘input’ to our mental states. It is not part of their functioning - that’s why they are disruptions.

What is the second possible response to Block’s China mind experiment?

The Chinese system is much slower than our brains.

What is Block’s objection to the response that ‘the Chinese system would be much slower than our brains’?

Why should this matter for whether it has mental states? Couldn’t there be much slower minds than ours? This is just an objection about what is physically possible. A Chinese system that operated as fast as our brains is still metaphysically possible.

What is a physicalist response to Block’s China mind experiment?

Perhaps we can combine functionalism and MBTIT as follows. If the Chinese system can have intentional mental states, then functionalism provides an accurate account of all mental states except for consciousness of phenomenal properties, which involves qualia. Why should this be? We could argue that the intrinsic properties of qualia depend on the specific physical properties of the system that realises the functional states. Patricia Churchland’s response to the objection from inverted qualia above can be elaborated in the same way. How colours look to us isn’t just a matter of what causes the colour experience and what effects it has, it also depends on our physiology - the way our brains are wired. So what mental states something has depend on its functional properties and its intrinsic physical properties. Mental states are still nothing more than physical states playing a functional role. A physical, functinal duplicate of a person with consciousness will have the same conscious states.

What is the knowledge / Mary argument as applied to functional facts?

P1. Mary knows all functional facts involved in colour vision.

P2. But she learns something new when she experiences colour herself.

C1. Therefore a complete functional account is not a complete account.

C2. Therefore functionalism is false.

What is a response to the knowledge / Mary argument as applied to functional facts?

Churchland’s original response. Qualia may appear subjectively to have an intrinsic nature which escapes a functional reduction. However, this appearance may be the consequence of us not being aware of detailed functional facts which ultimately constitute such mental states. We cannot know all these details precisely because we need to become appraised of our functional states in an efficient way. Awareness of colour is a kind of ‘shortcut awareness’ of a functional state. So if Mary really did know all these facts, she would be able to predict what it would be like to experience colour vision herself.