Functionalists think that what characterises the nature of the mind is not what it is made from, but what
it does. They therefore focus on asking what the mind’s function is.
They argue that all mental states can be characterised in terms of functional roles which can be
multiply realised.
For example, the functional role of pain is an unpleasant sensation that causes the organism to get
away from the thing that’s causing it harm. That function is what mental states - such as pain - are.
So, functions should be understood as what something does; e.g. a mouse trap performs the function
of catching mice.
Within the context of the entire mind, part of a function is to cause other mental states (for example the
desire for the pain to stop.
Throughout this essay, I will show how functionalism is not an effective account for the relationship
between the mind and the physical world.
The key argument that falls in favour of functionalism, is the multiple realisability argument by
Putnam, which helps us rule out reductive physicalist theories such as behaviourism and type identity
theory.
The basic claim of the argument is that mental states can be realised through multiple behaviours, a
fact that cannot be explained by reductive physicalist theories.
However, functionalism avoids this problem because the function of mental states is more than simply
behaviours - mental states can also cause other mental states (e.g. pain can cause the desire for the
pain to stop). It thus avoids tying mental states to specific behaviours, and thus doesn’t end up, for
example, giving circular explanations like behaviourism.
However, we could argue that it is logically possible that my experience of a red object was like your
experience of a blue object and vice-versa. This is called ‘inverted qualia’.
If that were true, however, there would be no way to tell from our behaviour since we would each
agree on what colour each object is.
When we both look at a blue object, e.g. the sea, our mental states would be functionally identical. So,
functionalism would have to say that they are the same, but clearly, the qualia are different. Therefore,
there is more to the mind than just function. Therefore, functionalism is false.
However, arguably there will in fact be functional differences between me and you. Blue is a relaxing
colour, while red is an energising colour. This is why, for example, doctors make stimulant medication
red and depressant medication blue, to add a placebo effect.
Therefore, if we would be encouraged to look at something red and then measure the levels of our
stress hormone, we would expect the one who really sees blue to have less.
Therefore, there is a functional difference, and so functionalism is true.
So, prima faciae it seems that the problem of an inverted spectrum does not affect negatively
functionalism, as the theory is still able to find differences between the two qualia. Thus, functionalism
seems viable.
Another major problem for functionalism is the issue of the possibility of a functional duplicate with no
qualia - this was presented by Block’s China Brain thought experiment.
Imagine a human body is connected to the whole population of China instead of a brain.
The population of China is similar to the number of neurons in your brain.
Imagine Chinese people, linked to each other with radios and microphones, each performing the
function of what a neuron would do. Then, the population of China collectively should be able to
replicate the function of a human mind.
Block’s point is that this is a functional duplicate of a mind, so according to functionalism, it should be
a mind. Yet, it is hard to see how that mind would have qualia (e.g. the distinctive feeling of pain) and
so it is hard to see how it could be a mind.
Therefore, functionalism is false.
