Functionalism Mind and Body Knowledge and Reality; Lecture 3

Recall the dualism vs materialism debate. The materialist says that science discovers what the world is like. Water… fire… thunder …now we know. We now even understand life itself. There has been amazing progress in understanding the world. The materialist’s idea is that, soon, even the mind will be understood and explained. And the idea or ideal here is to reduce mind to brain, for example pain to certain brain states.

Functionalism says, by contrast, that what we are made of is not important. Computer model of the mind. A.I. Hardware/software distinction.

What it is to be a certain mental states is its role in a system, not what it is made of. Mental states are (=) functional roles…. In particular. A) inputs of effects on the body. B) effects on other mental states. C) bodily behaviour.

Artificial intelligence (AI) We don’t need to worry about messy brain science, instead we can understand the mind by building a robot. The philosophy/psychology/computer science interface. The question is not: what are we made of? As Hilary Putnam says, we might be made of Swiss cheese or soul substance and it wouldn’t matter. Ned Block’s coke machine analogy. One state leads to another. One can give an abstract description of the coke machine. The same with us.

Two systems can be made of different stuff but be functionally similar (isomorphic). The kind of explanation appropriate for such systems is different… just as we can explain why we can’t put a square peg in a round hole without mentioning molecules… Different levels of explanation are involved. For example …. Pain tends to be caused by damage to the body, it tends to cause distress, and tends to cause us to wince. The state playing that role is (=) pain. And the same for other mental states.

It follows that mental states could be differently constituted. We could be made of chocolate, water. There can be space aliens with minds who are made of completely different stuff/substance? And … this means that psychology is autonomous of physical science. (That’s a matter of knowledge of mind.)

Functionalism: mental states are defined as dispositional-causal relations between other mental states and inputs and outputs. (Contrast with behaviourism.)

John Searle Objects to functionalism

Younger version

For functionalism, and AI: The brain is a computer, the mind is a program. Someone could write a program to enable a computer to simulate understanding Chinese. It passes the ‘Turing test’. Does it understand Chinese? His famous ‘Chinese room example’. (Choose another language if you are Chinese.) Imagine lots of Clerks in little offices shifting around tiles with Chinese characters on them.

Searle says, the room has syntax, not semantics. This is supposed to show that Functionalism is no good, and it can’t account for intentionality, the fact that we mean things, intend to refer to things in the world. But, as you know… philosophers always have replies….

The Holism reply The whole room understands Chinese although no individual clerk does. Searle says that this is question-begging?

The Robot reply Put the whole room in a robot, and have it move around, get content from inputs… In that case maybe ‘syntax’ does imply ‘semantics’. Maybe one can combine the holism and robot replies?

But is that enough to create meaning, that is, thoughts with worldly content? The input tiles might originate in a part of the world. But how does that make the sign on that tile a sign for that part of the world? Even if it somehow is, due to a regular causal account (Jerry Fodor), and these tiles are then processed in a complex system, that would not give the room a notion of truth, of correspondence with the world. But without that there is no intentionality.

So….. the functionalism and the AI program are controversial. Perhaps there are other problems with any broadly materialist approach…. In particular… from raw feelings….. As we’ll see …………………………………..next time…