The Intentional Stance

Reading

Lecture where this is primarily covered

Week 4: 'Instrumentalism'

If we wish to predict and/or explain behaviour, says Dennett, we may adopt any of three different stances.

1. THE PHYSICAL STANCE.

If science is on the right lines, it should in principle be possible to predict the behaviour of all physical systems by knowing the position of all the elementary particles they are made up of and the forces impinging on them.

This is the vision of Laplace in the 19th Century, that if you knew the position of all the atoms of the universe , and all the forces acting on them you could predict what the state of the universe would be at any moment in time.

More mundanely, I can predict the behaviour of the table I am sitting at by treating it as a physical object subject to the laws of physics. On that basis I think it will probably stay put for the foreseeable future. We can and do predict the behaviour of lots of things by thinking of them as physical objects subject to familiar physical laws.

'From this stance our predictions are based on the actual state of the particular system, and are worked out by applying whatever knowledge we have of the laws of nature.' (Dennett, in Lycan, p.168)

For a system as complex as a computer running a chess programme, the task of using the physical state of the machine to predict its future states would be prodigious - but possible in principle.

2. THE DESIGN STANCE.

If you take a clock - a clockwork clock - there is a new way in which you might predict its behaviour.

You could look at it, as in the above example, from the physical stance. You might try and apply physics to the parts and that might enable you to work out that in 15 minutes' time it will show 5 o'clock.

But you could also make this prediction on the basis of knowing that that it had been designed to tell the time.

You would then be adopting the 'design' stance.

'The essential feature of the design stance is that we make predictions solely from knowledge or assumptions about the system's design, often without making any examination of the innards of the particular object.' (Dennett, quoted by Stich, in Lycan, p.168.)

3. THE INTENTIONAL STANCE.

But sometimes there is a third possibility.

Sometimes you can get good predictions by assuming that the thing is rational.

You might predict the behaviour of a plant by attributing to it the aim of getting maximum illumination, and the belief that keeping its leaves flat towards the source of light is the way to do this.

Dennett is now in a position to define 'intentional system'.

Whenever, he says, one can successfully adopt the intentional stance towards an object, the object is called an intentional system.

He then explains what he means by being able to adopt the intentional stance 'successfully'. This judgement is to be understood as a pragmatic one. The test is whether the system's behaviour can be successfully predicted, 'and most efficiently predicted' ... 'by adopting the intentional stance towards it.' Whether the system 'really' has intentions, beliefs, thoughts, plans, desires, purposes or not is not the issue. The issue is whether by treating it as though it had these things, or things of this sort, you can predict what it is going to do. If you can, it is in Dennett's terms an intentional system. If you can't, it isn't.

By this test, some computers, good chess-playing computers included, are intentional systems.

Stich glosses the definition thus: 'Any object will count as an intentional system if we can usefully predict its behaviour by assuming that it will behave rationally. ' (Stich, in Lycan, p.168.)

END

• Are there some physical systems things to which the intentional stance cannot in principle be applied?
• Is Dennett a determinist?
  Enquire within.

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