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'In some manner, devolving from evolution's blind trials and blunders, densely crowded packets of excitable cells inevitably come to represent the world.'
Paul & Patricia Churchland
Contents |
| Introduction
The Representational Theory Of Thinking The Causal Account Of 'Hooking up' Two broad approaches to how the brain/mind works
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The structure of the rest of what I have said and will try and say about language is this.
1. An analytical tool that is often used in trying to understand language is the distinction between syntax and semantics.
In these terms:-
1a. Computers are very adept at handling syntax - manipulating uninterpreted symbols according to rules.
1b. How can they be thought of though as attaching meaning to uninterpreted systems (and strings of uninterpreted symbols)?
2. One theory of what is going on when a person is thinking is that states of bits of the brain represent propositions and these are manipulated in various ways. This is the representational theory of thinking.
3. There is another theory, which is the one sketched by the Churchlands in "Stalking the Wild Epistemic Engine".
4. The strong reasons for rejecting (3) and insisting that thinking must be quasi-linguistic need to be considered. Fodor's 'Why there has to be a language of thought' is the central paper here.
Some web stuff |
Think back to our discussion of 'folk psychology'.
It is people who think that our behaviour is to be explained by referring to beliefs and wants are said to be committed to 'folk psychology' - that is to say most of us, at any rate when no one is watching. We say he came in the back way to avoid being seen, and we accept that this is to be glossed like this: he wanted to escape being seen and he believed no one would be likely to see him if he came in the back way.
Suppose now you have a scientifically minded subscriber to folk psychology. What do they think is going on in the brain when actions flowing from a desire-want combination are being followed? For example, when I go in the back way to avoid being seen. They may think this. There is a pattern of activation in the brain which is/corresponds to my wanting to evade notice, and another pattern which is/corresponds to my belief that I will stand the best chance of not being spotted if I go in by the back. And then there is some kind of nerve circuitry which keeps a note of my beliefs and desires, and which initiates action when there is a belief and a desire related in the way that the belief and desire in my example are related - circuitry that identifies relations between a desire such as wanting to avoid being seen and the belief that going in the back way is the best bet.
| SENSORY INPUT | ---------> |
BELIEF BOX
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DESIRE BOX
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| ACTION |
The scientifically-minded person who presented this picture would be subscribing to the representational theory of thinking.
Prompt: Are you one?
On the representational view, thinking is a process of being responsive to symbols. In my example there are supposed to be two symbols, and a circuit which can pick them out from others and trigger a bit of behaviour.
DESIRE: I want to escape notice.
BELIEF: I believe the best way to escape notice is to go in the back way.
[ACTION: I go in the back way]
Also, thinking on this view involves symbols which stand for 'propositions'.
(I'm not saying exactly what a proposition is, but you will stay with me when I say that it is what a sentence expresses.
| IFAQ |
| Representing propositions |
The sentence "My brother is in London" expresses the proposition that my brother is in London. Beliefs are often said to be attitudes towards propositions: if I believe my brother is in London I have a believing attitude towards the proposition that my brother is in London.)
My example involves the belief that the back way offers the best chance of not being seen. But this belief involves a proposition. It involves the proposition that the back way is best. Beliefs are often taken to involve propositions.
Summary:
The representational theory of thinking involves the idea that activity in the brain symbolises propositions.
A belief is thought of on this view as something going on in the brain which symbolizes a proposition.
If they do, then some of the symbols (at least some) posited by the representational theory of thinking symbolise propositions.
It involves the idea that electrical activity in the brain symbolises propositions (and that this is what a belief in particular is: something going on in the brain which symbolises a proposition.)
Prompt: Is there anything obviously wrong with that? Who subscribes to it?
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Patricia Churchland and Paul Churland Pic courtesy Tom Ryckman |
One discomfort with the representational view is this.
Much of the behaviour that animals exhibit surely can't be controlled in this kind of way, via representations of propositions.
If we think of an amoeba moving away from acid, we surely can't think of this as it having a representation of a belief and circuitry to link this with representations of desire and so generate action.
You may want to ask why not, and I'm not sure I have a plausible answer. Let me just point this out: if you did attribute representations of beliefs to amoebae, you would be attributing to them beliefs as well. On the representational view, to have a belief is to have a symbol of a proposition in the brain, so if you've got the representation, you've got the belief.
Would you be happy to attribute beliefs to the amoeba? If you say: the little thing believes this or that, it sounds amusingly anthropomorphic: we don't really think amoebae have beliefs, do we?
So the critic of representationalism is saying: the behaviour of simple animals such as amoebae is not to be explained by referring to representations of propositions in their nuclei. Then the critic goes on: but the great majority of behaviour is like amoebic behaviour in this respect - not to be explained by referring to representations of propositions. (Do we correctly attribute beliefs to birds, beetles or badgers?) And the argument concludes like this: human beings have an enormous amount of their brain power in common with less evolutionarily sophisticated animals. Therefore, a great deal of their behaviour at any rate is unlikely to be controlled via representations of propositions. Therefore the representational theory of thinking holds for very little of human behaviour.
Summary
'Naturalistic' attack on representational theory of thinking:
Having a belief involves having a representation of a proposition.
The representational theory is committed to the thesis that behaviour is controlled by a process which involves brain representations of beliefs, which by (1) involves brain representations of propositions
Much of the behaviour of animals from which human beings have evolved is not controlled by such a process.
Much of the behaviour control mechanism in human beings is inherited from evolutionary ancestors.
Much of the mechanisms controlling human behaviour is unlikely to involve representations of propositions.
Prompt: Is this argument persuasive? If it isn't, where does it go wrong?
Critics of the representational view like the Churchlands ("Stalking the Wild Epistemic Engine") fasten on the way in which the brain is being pictured as working quasi-linguistically. It represents propositions, and what are propositions but what declarative sentences express.
Thinking as brain process has to involves representations, but they needn't be representations of propositions.
The naturalist suggests we view ourselves as 'knowledge engines', 'epistemic engines'.
We have to build knowledge out of what we sense in the environment and what we know already to inform our behaviour, to keep it well-adjusted to our situation.
'The planet abounds in with a wondrous profusion of epistemic engines; building nests and bowers; peeling bark; dipping for termites; hunting wildebeests; and boosting themselves off the planet altogether.... The problem consists in figuring out how epistemic engines work.' (Paul & Patricia Churchland, in Lycan, 2nd Edition, p.214).
In doing so, naturalists suggests de-emphasising language.
'Representations - information-bearing structures - did not emerge of a sudden with the evolution of verbally competent animals.' (Lycan, p.302)
The Churchlands make much of the metaphor of 'hooking up' to the world. It is a good metaphor.
Think of one of those electric model cars which you direct by remote control. They just do what you tell them.
But if you 'hooked them up' to the actual environment, they would control their own behaviour in the light of what their senses were telling them about their world...
The
causal account of 'hooking up' (cf intentionality)The causal account of how physical brain states could acquire intentionality - could get to stand for things in the environment - is tempting. Our senses pick up that a lion is approaching, and this causes a brain state, which then goes on to cause our muscles to move us to safety. If this is thought of as occurring again and again, you could think of brain states getting 'calibrated' (think of calibrating a thermometer).
'The backbone of what we are calling calibrational content is the observation that there are reliable, regular, standardised relations obtaining between specific neural responses on the one hand, and types of states of the world.' Lycan, 2nd Edition, p.308.
The Churchlands say the causal approach is promising, but stops being so if the assumption is made that it is a proposition that has to be represented...
Their own example is of a snake, which has what is called a pit organ. You can imagine the pit organ, and the rest of the nervous system, as a 'tuned' to certain features of the environment. It is tuned to go off if a warm moving thing occurs within half a metre.
If you have a set of neural cells which go off in this type of circumstance you can surely say that these cells represent the presence of a warm moving thing in the environment.
But, say the Churchlands, that doesn't mean there is anything with the structure of language in the neural system.
The Churchlands think of there being two rival traditions in play in current thinking about thinking.
The rationalist tradition emphases the rule-following, language-like aspect of cognition.
The unit of analysis is the 'propositional attitude'. (Paradigmatically, a belief.)
In cognitive activity, the transitions between representational states are a function of the logical relations between the contents of those states. E.g. I might derive the representational state that danger is approaching by putting together 'a lion is approaching' and 'lions are dangerous'.
Such representations and such transitions can be modelled on the von Neumann computer. The task of psychology is to work out the program which governs these transitions. And so governs the behaviour of the organism. The foundation for working out this program are given in folk psychology.
The naturalist approach is inspired by two thoughts.
One is the conviction that human beings have evolved from very much simpler systems.
The other is that it is normal for first thoughts to be replaced by second thoughts. Folk psychology is a first thought. We should be in the least surprised if it has to be replaced.
The starting point is animals in general, some of which are enormously simpler than the human being. Language is a late comer on the biological scene - an extremely recent development - and it seems unlikely that language-like structures will have been involved in the cognition before language itself arose.
This is the tradition of the neuroscientist and physiological psychologist.
END
Lion pic courtesy USA Today
Revised 11:04:03
