Functionalism

Reading

Lecture where this is primarily covered

Week 9: Functionalism

EXPLANATION OF 'FUNCTIONALISM' AND HOW IT RELATES TO IDENTITY THEORY AND EPIPHENOMENALISM.

Scientifically-minded people are sympathetic to the claim that thoughts are to be identified with states of the brain: identity theory.

Or with the idea that thoughts are given off by states of the brain as a kind of effluent: epiphenomenalism.

The temptation with both these approaches is to think that a token thought either is, or is given off by, a particular brain state.

But what do I mean by a particular brain state?

Possibly: think of opening up a brain and pointing to a particular bit of it, a particular network of interconnecting neurones.

My twinge of toothache, says both the identity theorist and the epiphenomenalist, is the firing of that particular network. When that particular network goes active, I feel a twinge.

The identity theorist says: because that is what the twinge is.

The epiphenomenalist says: because that is what gives off the twinge.

Let me put this in the concrete terms that you find in the literature. It used to be thought that there was a particular kind of neuronal link that was associated with pain - what they called the c-fibres.

When the c-fibres were firing you felt pain. If they weren't, you didn't.

Assume this is still a plausible hypothesis.

Then you might say, if you were an identity theorist, the firing of that batch of c-fibres is the pain.

Or you might say, if you were an epiphenomenalist, the firing of that batch of c-fibres gives off the pain.

So you would say, the physical side of pain, or the physical grounding of pain, is the firing of the c-fibres.

But this position was thought to be vulnerable to the following objection: It seems to rule out creatures who lack c-fibres from having pain.

Supposing you found a sort of animal on another planet, which seemed to behave very like a badger, but which turned out to be made of silicon or something, with not a c-fibre to its name. If pain simply was the firing of c-fibres, we could never entertain the idea that this new creature might be capable of feeling pain. Or if we took the epiphenomenlist position that pain was a mental state that was produced by the firing of c-fibres, again we would not be able to think of this Martian creature as capable of pain.

Or think not of a Martian badger-type creature made of silicon, but of one of our own dolphins. A very sophisticated animal we might think, and then discover that its nervous system was not at all like ours; and in particular that it didn't have any c-fibres. Again if it were true that pain is or is grounded in the firing of c-fibres we wouldn't be able to think of the dolphin as capable of feeling pain.

Do you think that a creature with a very different nervous system from our own might nevertheless feel pain? Does this prove physicalism wrong?

These implications of physicalism, in the two forms considered, were held by some to be unacceptable.

The functionalist theory was put forward to remove this type of objection.

Pain, it was said, might be associated with c-fibres in humans, but that would be because of the job c-fibres performed. In another creature, the role played by c-fibres in us might be performed by something else. In that case, pain would then be associated with whatever was the 'equivalent' of c-fibres.

I've explained this in terms of pain, but the functionalist approach generalises the point.

WHAT IS A 'FUNCTIONALIST' APPROACH?

It looks on the brain and nervous system as a machine capable of being analysed functionally. That is to say, we can look at it as made up of a set of subsystems, each of which does a particular job in keeping the system as a whole working.

A running car would be a simpler example of something we can analyse functionally. There is a system to feed fuel into the cylinder, a system to keep the pistons positioned ready for each explosion, a system to transmit the up and down movement of the pistons to the wheels and so on.

In any particular car, each of these is done with a particular piece of hardware. The pistons for example might be aluminium in one model and steel in another. Different materials, maybe a different arrangement: but same function.

From the point of view of functional analysis, you could say that cars with petrol engines are all functionally the same. There are lots of differences in how in detail the functions are carried out., but carried out they are. If it is a petrol engine something has to feed the fuel into the cylinders. That is a function that has to be performed. And there are plenty of others - functions that have to be performed if the car is to keep running, but functions which might be carried out in a wide variety of different ways, using different materials, and different designs.

Often what is said is that the same function may be realised in different ways.

Can you think of examples of where the same function is realised in different ways? A suggestion

It has long been suggested that we should think of the brain in the same way - as a machine which it is sensible to analyse functionally. This bit does this, that bit does that. If these functions are not performed, according to this line of thought, the role of the brain in controlling the body in a way that is well-adapted to its environment will not be carried out successfully.

If you adopt this way of thinking, you will not object to the idea that you might draw up a list of functions that you work out must be essential. You could then think of giving that list of functions to different engineers, and they might come up with quite different control devices, any of which would do the job.

THE PHYSICAL BRAIN AS A HARDWARE PLATFORM

A way of thinking that is only a little different from this is to think of the brain as a computer running a program.

So long as the program runs successfully, the brain does its job. But it is in the nature of a program that it could run on different machines, and if proper arrangements are made, on different types of machine. (Think of Word running on an PC, or on a MAC: two quite different pieces of hardware are involved, but because they are running the same program, you get the same effect whichever machine you run it on. The jargon says: the same piece of software can run on several different hardware platforms.

The great attraction that functionalism exerts today is probably due to this analogy. Functionalism appeals to the analogy of the brain as a piece of hardware running software. It is an analogy that supports the idea of it being possible for the same software to run on different hardware platforms, and that from the point of view of getting the controlling job done, it is the software that matters. The hardware has to work, but how it works doesn't matter.

An attraction of this perspective is that according to it when a physical brain is damaged or dead there would be nothing in principle to stop the software being downloaded onto a different and perhaps more robust hardware system.

The general point is this:

The functionalist theory of the mind holds that mental things are tied not to particular ways in which functions are realised but to functions.

IMPLICATION OF THE FUNCTIONALIST PERSPECTIVE: IT SUPPORTS A DISTINCTION BETWEEN PHYSICAL AND MENTAL

Now just think of the c-fibres that are in me, and assume I have toothache. Those c-fibres are firing, and there firing is, or is the physical grounding of, my pain.

But if the functionalist is right it would not be correct to say simply that pain is the firing of c-fibres. In a silicon-based creature, it might be the activation of the frontic nexus that performs the relevant function. In that case if you take a particular creature with toothache, its pain will be, or will be grounded in, the activation of its frontic nexus.

So if we are trying to say what pain is, we shall have to distinguish between the pain that a particular creature has (e.g. me, or the Martian badger) and pain as a phenomenon that transcends particular cases.

If you do, you should be able to write down a sentence in which a token intention is referred to. And another in which an intention but not a token intention is referred to. Like this.

TOKEN AND TYPE MENTAL STATES

Now let me use this distinction to help state more clearly the functionalist account of pain:

Token physical states ground token pains.

Type-pain is grounded in the function performed by those physical states.

THREE LEVELS OF DESCRIPTION OF ONE AND THE SAME PHYSICAL SYSTEM

The type/token distinction also helps me make another point.

Think of the network of c-fibres in me and the token-state they are in at a particular time.

I can offer a neurophysiological description of that state. (Arrangement of neurones, their size, their activity etc.).

But if the functional perspective on the brain is right, I can say a second thing about that system of c-fibres in me: it is realising a function.

Compare: two descriptions of the lung:

• a piece of tissue of such and such a size and weight, with such and such an internal structure.
• An organ for getting oxygen into and out of the body.

Can you think of another example of one thing but two descriptions, one functional and one structural? A suggestion

So we have a way of understanding how one and the same system of c-fibres may have both a neurophysiologcal description, and a functional description.

There is a third thing. That self-same system of c-fibres in a certain state of activation may also be, if the functionalist is right, a pain or the physical grounding of - a token pain.

So three levels of description of one physical system:

• neurophysiological (physical)
• functional
• mental

Notice though that the mental description, on the functionalist view, is attributable in virtue not of its physical nature, but of its functional role.

So for functionalism there is a divorce, though of a subtle kind, between mental and physical.

The physical supports the mental, but only in virtue of the function the physical performs.

Lycan puts it like this:

'And so there is after all a sense [if functionalism is right] in which 'the mental' is distinct from 'the physical': though there are no nonphysical substances or stuffs, and every mental token is itself entirely physical, mental characterisation is not physical characterisation, and the property of being a pain is not simply the property of being such and such a neural firing.'

Lycan, Mind and Cognition, p. 8.

END

Does functionalism in this context have anything to do with functionalism in sociology? Saith the Wise

Tester

An objection to the functionalist view?