This essay assesses functionalism, a material monist theory of mind that develops behaviourism is asserting that inputs to the mind (qualia) are transformed by functions before being output as behaviour

Functionalism is a material monist theory of mind: it asserts that everything is physical. It is highly significant both in that it develops behaviourism and that it paved the way for empirical work in neuro-physiology and cognitive science. It was created as Hilary Putnam interpreted conscious states in terms of the (then new) science of computational theory.

The function of the brain, states the theory, is 'consciousness'. This approach is useful because by reducing the mind to a function it does away with the issue of how that function is performed. A function can be defined abstractly, without concerning itself with how that function is discharged in the same way that an equation can specify the relationship between X and Y without needing to specify how that equation might be solved. Thus, functionalism avoids the question of how the brain might achieve the feat of consciousness that dogs other materialist theories.

Functionalism is also both a response to and a development of behaviourism. Behaviourism argues that conscious states can be understood in terms of sensory input and behavioural output. This leads to a significant issue; namely that it ascribes conscious states to any input/output system (e.g. a water tank). Functionalism adds an intermediary step, arguing that sensory input is processed by a function before output.

Thus, two crucial differences to behaviourism are introduced: the function can lead to one or many outputs and some or all of the output can form the input to another internal function without the requirement for external expressive behaviour. With this simple device the diversity of the mind can theoretically be accounted for.

An everyday illustration of this process might be a car. It receives multiple inputs in the form of petrol, oil, water, etc and outputs motion, gases, heat, etc. During this transformation process (function) we can also see an example of feedback: some of the motion of the car is used to power the alternator to generate electricity, which in turn forms one of the inputs to the combustion process.

So now we have a brief understanding of the theory let us examine why this important theory came about. Firstly there is the need to respond to behaviourism and to overcome its shortcomings.

Functionalism can also be seen as developing along with other new concepts of the time. The new science of computers and computational mathematics supplied concepts that could be applied to the brain as a complex system. Functionalism was also applying empiricism to a new area, paralleling the method of the huge advancements made in science in the twentieth century.

One of the benefits of functionalism is that by equating conscious states with functions of the brain, it (at least in principle) allows for external investigation of conscious states. What makes this investigation possible is the fact that brain functions are not private. They can be publicly observed (given the technology) thus rendering our conscious states public. Some previous theories (such as Cartesian dualism) had ascribed radical privacy to mental states. This lead to the problem of other minds whereby owing to privacy it was not possible to compare mental states between minds, or even know that other minds existed at all! By providing us with a route to others' experiences, Functionalism solves this issue.

The theory also benefits from the ability to empirically test it: the theory is independently verifiable, a somewhat unusual position amongst philosophical theories and of obvious superiority to other theories of mind (such as dualism or idealist monism).

A further advantage is that in developing behaviourism, the theory offers progress in our understanding of the mind. It takes the benefits of behaviourism (solving the issue of other minds, allowing empirical observation of the mind) and introduces multiple outputs and feedback. This additional complexity solves the major issues with behaviourism (perceived crudeness, varying outputs from same input, zombie objection, super Spartan objection, etc)

However, functionalism is far from a panacea to the problems of the philosophy of mind. The first issue is shared by all materialist theories: it fails to explain the apparent radical difference between physical and conscious states in our perceptions. For example I might be the worlds foremost neuroscientist, but even then I would not understand my experience of eating breakfast in purely physical terms. I understand a pleasing breakfast by thinking, 'mmm, that bacon has caused an excitation potential to be reached and thus link the X and Y areas of my brain', but I might think that it was delicious.

Another criticism is that despite the introduction of additional complexity, functionalism, like behaviourism, ascibes consciousness in very simple systems such as computers. This is perhaps the danger of borrowing a concept from computational mathematics and applying it to consciousness: that this will equate maths and consciousness as the same thing! If a strict definition of a function (as any sort of process) is followed then theoretically anything could be ascribed consciousness.

There are two further 'set-piece' objections. Firstly, Frank Jackson argues in 'Epiphenomenal Qualia' (Philosophical Quarterly, 1982) and later in 'What Mary Didn't Know' (The Journal of Philosophy, 1986) that it is not possible to ascertain someone else's experience from direct observation of the physical processes of the brain. Secondly, the Chinese mind argument argues that a system that mimics the functionalist explanation of the human brain does not exhibit consciousness.

Let us first examine the arguments of Frank Jackson. His arguments are two stories: what Fred knew and Mary didn't:

What Fred knew:

1. Fred has a capacity that no one else has
2. Fred sees two varieties of red where everyone else sees just one
3. Experiments with tomatoes force us to conclude that Fred has this unique ability
4. If functionalism holds true then surely by examining Fred in sufficient depth then we too can experience the difference between these colours?
5. Jackson argues that we can know everything about how Fred physically accomplishes this feat, but cannot thus experience the sensation of seeing the additional colours.

What Mary didn't know:

1. Mary (through a convoluted set of life events) has never seen colour - only experiencing in black and white
2. Objection one: if she were able (from within her black and white prison) to study someone else whilst they perceived colour, then she could (according to the functionalist) know what it was experience to colour. Jackson holds that this is false.
3. Assuming the happy day arrives when Mary gets released from her prison and she emerges into the world of colour, the functionalist would hold that we could capture her unique experience by analysis of her physical states. Again Jackson holds that this could not be done.

In the Chinese mind argument another set of unusual circumstances occurs:

1. The people of China are arranged such that they can all see a billboard
2. On each billboard is written an order and each person reacts to this order
3. When each person sees the order (input) they perform a function which in turn leads to an output
4. This system is thus directly analogous with the functionalist account of mind, and if functionalism were the case would be a system that was conscious.
5. The argument states that this clearly is not the case, hence functionalism is not the case either.

A further objection, which can again be levelled at many materialist monism theories, is that a purely physical description of the mind requires the laws of cause and effect and thus provides a deterministic account of the mind. However, this objection is not a refutation, but it does jar with our experience of the world. It may also be further weakened or by mathematics, which shows that chaotic (and thus unpredictable) behaviour is a property of very complex systems.

The final objection is the homunculus problem. Essentially, this objection argues that the burden of explaining the mind is shifted to explaining the function. If the process of the mind is that input (perception) is processed by a function and then expressed as outward behaviour, this begs the question of how the function works. If this is in turn analysed according to the functionalist model, will the function that the answer invokes not also be subject to the objection thus creating an infinite regress?

In response to this problem it can be argued that interrogating any networked system in this way appears to generate the homunculus problem. However, in the case of a interlinked network (such as the human brain) a property of that type of system is simply that repeated questioning leads to an infinite regress (as with any system with no beginning and end) owing to the possibility of getting into loops. The problem occurs simply because our method of analysis is incompatible with the thing being analysed.

However, whilst this response may answer the accusation of infinite regress it does not answer the accusation that functionalism merely delegates the central issue by failing to explain the function.

Therefore, in conclusion to this assessment of functionalism we can say that it forms a significant and useful theory, and that it is a useful model for comprehending how the mind might work. However, a model is all it is (i.e. a device for simplifying comprehension of a complex concept) because it admits of consciousness in simple systems and does not confine itself to those systems that are self-aware. It also falls short of solving the problem of privacy of experience and subjectivity. Thus, it fails to provide a complete picture of the mind and consciousness.

Tutor: Oliver McAdoo MA

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