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Introduction to Philosophy |
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introduction causality - two broad approaches david hume on causality The challenge of 'indeterminate' physics kant on causality |
Reminder: remember that compatibilism is a form of determinism. It does not compromise on determinism. It accepts that all events are completely determined. Only it says, we can nevertheless describe some of them as 'free'.
We have been speaking a good deal about causality, causes, the causal principle and so on. It is time to issue the time-honoured philosophical irritant: Yes, but what do these words actually mean ? Exactly what is a cause? Exactly what does it mean to say that A is the cause of B?
We shall find this question ridiculously hard to answer, and it is worth pausing to muse on this fact. Over and over again in philosophy you will find it frustratingly difficult to answer questions about the meaning of words, so much so that you can take the view that philosophy just is the attempt to get clear about the meanings of key words like cause or time or responsibility.
You remember I said that one conception of the nature of philosophy was that it was the pursuit of peculiarly resistant, otherwise unplacable, problems.
If this is right, you could argue that this type of problem can only concern words, or the way we think. There can be no intrinsic paradoxes or difficulties with the world itself. If difficulties there are, they must all be based in human being's attempts to represent the world, so we can talk about it. Philosophy then is concerned with conceptual hygiene - of making sure the framework of conceptions we construct to talk about reality is coherent and well-suited to its task.
Let us notice then that there is no apparent reason why simple questions about meanings should be difficult. They always are, but why? Why shouldn't it be easy to say what 'cause' means? -What 'good' means? - What 'God' means?
I am sliding between two ways of poses the question: what is a cause? and What do we mean by 'cause'? Let's not bother about this for the time being.
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There are two broad approaches to this question. One is that there really are connections between things. The other is that there are not.
The first option is going to be really difficult for me to get across to you. It's not complicated, just strange, utterly strange. If you get to the point of seeing it you will probably find it pretty silly, unthinkable. I can only ask you to think about it even so, not dismiss it without further ado as obviously wrong.
Let me have a first go by saying something very paradoxical.
The strange thought is that maybe although the events that occur in the world fall into various patterns, it is a mistake to think those patterns are brought about by anything.
Take an example. Think of the movement round the sun of the planets, of which the earth is one.
Each planet pursues a pretty exact path, an ellipse, and it moves at a speed which varies in a precisely describable way. Its path can be exactly predicted. So can its speed. For any time in the future.
That is what I mean by events following a pattern. We have in the planetary movements an extraordinarily simple pattern, which is why I choose it as an example.
It is a pattern that can be described in words, and also in mathematical formula, in the sense that you can write formulae which will express the precise relationship between position, velocity, acceleration.
Before we start philosophical thought, and maybe afterwards, I suggest we assume that this pattern is produced by something. We would probably put it in terms of something we call 'forces'.
I don't know what sort of a detailed story we would be able to tell. Some of us anyway would be prepared to say that the sun exerted a force which pulled on the planet, and it was this that kept the planet whizzing round and round - instead of whizzing off in a straight line. It is a force that gets stronger as the planet gets closer to the sun, and this is what makes the planet travel faster as it approaches the sun. And you may be able to add more, explaining in more and more detail how the forces acting between the two bodies result in the pattern of movement we are talking about.
I'm not interested in the details. The one and only point is that most of us I'm sure, and all of us before we encounter philosophy, would say that there must be some such explanation in terms of forces.
Or at least, if not forces, then something else. The point is, there needs to be something that brings about the regularity.
That is what most of us would say, I think.
And that is what the school I am gong to refer to as nothing-behind-the-scenes-ism would deny.
Let me try this ranging shot:
there are regularities, patterns: but that is all.
This is a ranging shot, because it doesn't give the full subtlety of their position on this question. I am putting it to you to give you the general idea, because it is a strange and sort of extreme one.
It is saying: the planets go round the sun in a perfectly regular, predictable way. Their movements follow a pattern, a simple pattern as a matter of fact, and we can describe it. But there is nothing producing the pattern! There is just the pattern itself.
This is the view expressed in the harmless-sounding doctrine you can find in thje Ayer article, the view that laws of nature just describe the pattern of events.
In the case of the planets the positivist view is that Newton's laws of mechanics describe the pattern of movement.
I have not said anything about the connection between laws of nature and causality. There is a connection of course. But I don't want to get side-tracked now.
The one and only big point that I want to get across at this stage is that there is a view, the nothing-behind-the-scenes-ist view, which maintains that behind the regularities we can see in events, behind the patterns, there is - nothing.
Call this view nothing-behind-the-scenes-ism, or nothingism for short.
Is this intelligible? Can you have a pattern and nothing to explain it?
Let that spin in the brain a little.
So there is a view that there is nothing producing the regularities that we see among the events around us, the patterns we see them fall into.
This general perspective has been applied to the question of what a cause is. This perspective says: Whatever the cause of a thing is, it isn't something behind the scenes.
Ordinarily we do think of a cause, in a certain sense, as behind-the scenes.
Take a tennis racquet hitting a tennis ball. The ball comes into contact with the racquet and then shoots off back from where it came.
What is the cause of its shooting back?
A first answer is this: it's being hit by the racquet.
Yes. But what is it about the ball's being hit by the racquet that makes it fly off? I think what we think is: the racquet gives the ball one helluva push.
It is this push which is the actual cause of the ball shooting off.
If there wasn't a push when the racquet came into contact with the ball, it wouldn't shoot off.
Now it is said: this push, the actual thing that brings the change in movement of the ball about - the push is not actually visible. The push is something you don't actually see.
What do you see?
You see the ball flying towards the racquet, you see if the whole thing isn't too fast, the ball coming into contact with the strings of the racquet, and you see the ball flying off with its direction of movement reversed.
You don't actually see the push, the actual cause of the reversed movement.
You see a series of events, of movements. But you don't see the thrust, the push, the impetus, the actual cause.
The philosopher David Hume was much exercised by this thought.
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| Hume putting in an appearance with some of philosophy's best. |
He was more used to billiards than tennis and he conducted the argument in terms of billiards.
It was not just Hume who thought billiards I may say: it was a game much in favour in the 18th Century by those who had the leisure to indulge.
I can show you some billiard balls.
The question is, as you watch them run and bump, what do you see?
Suppose I leave one still and run the other into it.
What do you see?
You see one ball moving in a certain direction.
You see it come into contact with the other.
You see both balls move off, the first one moving in a different direction.
Anything else?
So far we are admitting to seeing a sequence of events.
Would zooming in a little help? Does this reveal anything we have been missing? Would it help if someone were to come and peer even more closely?
Hume says at any rate: the one thing you don't see is any kind of actual push . All you see is a sequence of events.
If you accept this claim, what conclusion does it warrant?
One conclusion you may be tempted to draw is this:
Causes, the actual pushes, forces or whatever, that actually bring change about are not observable. If they are there at all, they are 'behind the scenes'. We see what they bring about, but we don't see them.
Hume himself saw the force of this, but felt obliged to draw a quite different conclusion.
What he felt the force of was the thought that if there really are 'pushes', 'forces' etc. that are actually responsible for bringing change about, they are not available to observation. If there are such things they must be behind the scenes.
But he drew the conclusion that if we have to think of them as behind the scenes, we cannot believe in their existence at all.
Hume drew this conclusion because of a quite separate belief of his. He thought that in general, words get their meanings by standing for things we have observed.
(Think of 'yellow, 'banknote', 'quickly'.)
So the word 'cause' cannot, according to Hume, stand for the unobservable pushes, forces etc. that might be postulated to be at work behind the scenes. He says to all this talk of things going on 'behind the scenes': Pish!
If a thing cannot be observed, then we cannot attach any sense to the word we are trying to use to refer to it.
So 'cause' cannot mean the hidden push that brings things about.
Later, I will return to the question of why it might be plausible that you can only make sense if you restrict yourself to what can be observed.
For now I want to point to where his denial of sense to 'cause' as push or force lands him.
Where does this land Hume?
He has two options. One is to stop talking about causes. To say we have just made a very long term mistake about them, trying to talk about things we can't talk about, unobservables.
The other option is to say that 'cause' doesn't refer to something unobservable at all. Properly understood, properly interpreted, properly construed, the word 'cause' refers to what can be observed after all.
Hume took the second.
How then did he suggest we interpret 'cause' so that it only involved what could be observed?
Crudely, in terms of the billiard balls, he said that to say A's bumping into B is the cause of B moving off is to say these are two events that always go together. The two events are:
A's moving up to B, coming into contact with B; and
B's moving off (in a certain way)
These two events belong to a pattern in which events of the first type are always followed by events of the second.
To say one event is the cause of the second is to say they belong to a pattern of this kind.
Nothing about unobservable 'pushes' behind the scenes. A cause is a certain kind of regularity among the things we can observe, events.
This is the regularity view of causation.
You may find it at this stage completely unconvincing.
You will have to take it from me that it deserves thought, some of which I hope to devote to it, in a roundabout way, below.
Many people raise the objection that the principle of causality does not really survive quantum physics. Physicists say some events at the micro level - at the level of electrons and - do indeed happen unpredictably, spontaneously. If they tell us this, who are we to disagree? Mustn't we just accept that the principle of causality is just untenable?
Electrons jump orbits, they say, in this uncaused way. There is a jump, from one orbit to another, but nothing brings it about. It just happens spontaneously.
This breaks with the principal of causality. Here are happenings without the happenings being caused.
Let's have a go at this.
The first thing is: can we understand what is being claimed here? Do we understand the very idea of something happening spontaneously? I can't see that we don't. It seems to be perfectly intelligible.
But there is a problem about it. What was it that led physics to say definitely: here is an event without a cause? What the rest of us in ordinary circumstances would say would be: here is a real puzzle. This thing happens, but we can't see what causes it. We've looked and looked and looked, but we can't discover the cause. How interesting!
Would there come a point when we would conclude that we had exhausted every possibility? Would there come a point when we could announce with confidence that we had reached a definite conclusion: that here we had before us a most interesting monstrosity, a real curiosity as it were: an event without a cause.
Ordinarily we wouldn't - surely. If we hadn't been able to disentangle the causes of a particular phenomenon we would say, wouldn't we, and go on saying: it's a really recalcitrant problem, a real bugger, but we are still working on it, it's really important, please give us even more money and one day we shall have cracked it. For example: the search for an understanding of cancer. We don't say, do we: alas, these tumours just happen. Nothing causes them. They just initiate themselves spontaneously. No good researching. No good experimenting. We have tried all that and got no where. We must just acknowledge that these things happen.
What does this establish? Could we try this: that physics, in appearing to posit uncaused events, has got itself out on a limb, taken itself off into a world of meanings and understandings that are not ours. When they say here is an event without a cause, we don't really understand what they are saying, because we don't really understand what can have forced them into this conclusion. If we did understand that, we might be able to propose an alternative.
I'm not saying that the claim by physics that some events are uncaused can simply be discounted: but it is more complicated than its seems. We can't just take it as a 'result' or 'discovery' by physics and use it to disprove the causality principle.
What I hope I have brought out is one important feature of the character of the causality principle. It seems to be as much an assumption as a conclusion. It is not that over the decades as result of much experimentation and observation we are moving with ever greater confidence to the conclusion that every event has a cause. It is rather that from the beginning we approach our research on the assumption that we should be looking for causes, and that causes will be there to be found.
Of course you may say that this assumption has been born out by and large over the years. I suppose that relies on there having been more successes in the search for causes than failures. I'm not sure if this is correct.
Let us leave that undecided. At least it is a possible thought that the principal of causality is a sort of guide, a rule, an assumption perhaps rather than something like a disprovable hypothesis.
I am speaking here of the principle of causality being an assumption. A much stronger claim, but one you arrive at by going further in the same direction, would be that the principle of causality is a true assumption. This is the claim that we can know before we undertake any experiments, any observations, any enquiries, that every event has a cause. It is an assumption on the basis of which we approach all our experience, but it is a true one.
This raises the little question of how we can know it. But let me remind you of the label for what we are talking about here: 'a priori'. Some people, I think at least about 60 people in this room, think that you can know a priori that time travel is impossible.
A priori knowledge is knowledge you have independently of any experience. It is contestable whether there can be such. Plenty of people say: everything you know has to come from what you are told, or what you find out by looking - by observing, by experimenting. These are people who deny the possibility of a priori knowledge.
Those who believe there is such a thing, that there are things we know independently of what we find out through observation etc. have in mind a variety of examples.
Here are some candidates I prepared earlier:
A real ragbag here: just to whet your appetite.
The most interesting defence of the idea that the principle of causality is something we know a priori is by Kant.
It is true, according to Kant, because it is part of the framework through which we make sense of the world.
We bring it to all our experience.
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| Kant dropping in on one of our History of Philosophy seminars last year. |
His basic idea is that we know it to be true because we bring it to all our experience.
It is like a person wearing rose-tinted spectacles. Everything looks lovely. Not because of anything out there in the world. But because of the spectacles through which the person looks at everything.
If you say this makes the principle of causality more of an assumption than a piece of knowledge, I won't argue at this stage. To take that distinction further we would have to go deeper into Kant. But at any rate we can say that it is not an assumption in the sense that we can think of throwing it over, or discarding it. For Kant it is an absolutely basic condition of our having the experience of the world we in fact have.
Let me explain that just a little. Again as an appetite-whetting exercise.
Kant said we cannot avoid having the conception of a cause.
Without it we would not be able to make the distinction between ourselves and the external world.
We would not be able to treat some of our experience as figments and some as perceptions of a world independent of us.
His idea was that to make this distinction there has to be two possible orderings of experience.
One is the one they occur in to us. The other is the one they occur in independently of us ...
How so?
Think of what it
is like first looking at a house. We stand and look, and as we look we see the
front door, the windows on either side, the fist floor windows, the roof, the
chimney. Imagine that we are not seeing these things all at once. Our eye, our
attention, roves over the house, giving us a succession of visual experiences
- the door, the windows, the first floor, the roof.
Then contrast that experience, or sequence of experiences, with this one. You are on the bank of a river watching a boat go by.
What governs the order in which we have these experiences? When we look at the house, we can to an extent choose - we can look at the roof first and then the chimney, or we can look at the door and then the roof and then the chimney etc.
But in the case of the boat going by, it's not up to us in the same way. The order is fixed by the world outside us. We see the front of the boat first because it is the first to appear. And so on.
Kant makes the point that we couldn't make this distinction, the distinction between some experiences that are ordered by ourselves and some that are ordered independently of us unless we acknowledged the concept of causation. If we didn't have that concept we wouldn't be able to make the distinction, and our experience would be very different from the way it is. It would be a single sequence of experiences only: one damn thing after another. We wouldn't be able to attribute some experiences to the external world and some to changes in us.
Our belief that there is such a thing as causation enables to think of some sequences of experience as determined outside us. It enables us to have the concept of an external reality.
I'm afraid I have slipped from talking about the principle of causality to talking about the concept of causality, which is indefensible. The truth is that Kant's argument is a plausible account of the importance of our having a concept of causality, but probably doesn't establish the importance of the principle. To make a distinction between our inner experience and the external world we need to think that some events are caused, but it is not obvious that we need to believe every event has a cause.
What then would experience be like if we did not believe in causality?
Can we imagine this? What would it be like? Would it be a world in which anything happened, in any old order? A world in which once one thing had happened, anything whatever might follow it?
Would it be like one of those awful videos where the attempt is to produce something artful and all that results is a hopeless mishmash of unrelated images, one after the other?
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