Final. Okay.
So now we come to humans argument concerning induction.
And you will find on the reverse of your handout a diagram.
Which outlines the argument of treaties. One, three, six.
Now, I'm not actually going to be going through this in detail.
But I've put it there because I think when you read through one, three, six, it will be helpful to understand how the argument is structured.
As you can see, it's quite a complex argument. I'm understanding how this relates to discussions of human induction can sometimes be difficult.
We'll see why. Well, there are three versions of this famous argument.
The first is in treaties one, three, six.
But it seems to me, at any rate, that HUME in the treaties does not really quite appreciate the significance of this argument.
He slots it in here, as we've seen as a detour. It's fitting into a structure whose aim is to find the origin of the idea of cause.
He's clearly very interested in probable inference, probable belief.
But he doesn't seem to realise what a jewel he's hit on with this argument.
Now in the abstract, which was probably written only eight months or so later, it wasn't published till 1740.
But it was probably written around September, October 1739.
We got a striking change. The abstract as a whole is very condensed.
But the argument concerning induction in the abstract is something like three quarters, as long as the argument concerning induction in the treaties.
And that's rather surprising when you take a large work like the first two
books of the treaties and you shrink it to something as small as the abstract.
You would expect that the argument concerning induction would reduce to just a paragraph or two.
Very far from it, it occupies centre stage. And when we get to the inquiry published in 1748,
the the argument concerning induction is yet more full and occupies section four
and one can see most of the rest of the inquiry or significant chunk of it anyway,
as spelling out the consequences of Hume's theory of induction.
So I think in the case of induction, if we want to understand what HUME is about,
we do need to pay careful attention to the inquiry as well as the treaties.
So much of what I say here will be derived from the inquiry argument rather than the treatise argument.
But I will be saying things about how they link. So here's a very brief overview of the argument.
Suppose we say we see A followed by B. Again and again and again.
Next time we see an A, what happens?
We expect to be to follow. Why do we do that? Well, is it a priori insight?
No, because a priori we can't know anything about the causal effects that they will have.
It must be based then on extrapolating into the future the associations that we've observed.
Since we can't a priori I know the table calls B it must be our experience of being followed by B,
which leads us to make this inference, and that involves extrapolation from past to future, from observe to unobserved.
Okay, so what grounds can we give for extrapolating from observed to unobserved?
Is it based on sensation? No. When we perceive objects, that doesn't tell us anything about their causes or effects.
Only experience does. What about logical intuition?
Is it self-evident that what's happened in the past will happen in the future?
No. We can easily imagine it not happening in the future.
That also shows it can't be demonstratively proved.
We can't give a demonstrative argument that what's happened in the past will continue in the future.
Because if we could, it wouldn't be conceivable that anything else would happen.
But we can easily conceive of different things happening, see one billiard ball moving towards another.
It's very easy to conceive that the second billiard ball won't move or that it'll jump into the air or disappear or all sorts of things.
So the can't be a demonstrative argument to prove.
The next billiard ball will behave in the same way as all the billiard bulls before.
What about probable reasoning, moral reasoning, reasoning concerning matter of fact, what we now call inductive reasoning?
Well. This whole argument has been for the conclusion that such reasoning depends on the assumption that the future will resemble the past.
So clearly we cannot use probable reasoning to draw that inference.
So what I've given there is an outline of the argument as it appears in the inquiry.
Now in the inquiry. HUME does seem quite explicitly to rule out intuition as a source of the principle of extrapolation.
He also discusses at some length whether a sensation can ground such an extrapolation sentence as it can't in the treaties.
You don't get that. In the treaties, as soon as he's identified this move of extrapolation, what's commonly called his uniformity principle.
He immediately goes on to say, Well, can this be founded on demonstration or probability, knowledge or probability?
And he doesn't consider any other possible sources of foundation.
Now, obviously, you could claim or think that that suggests a fundamental change of perspective between the treaties and the inquiry.
I don't think that. I just think the inquiry argument is more complete.
I think I think in the treaties, when HUME came to the point of saying,
how can we justify this principle of extrapolation from observed to unobserved?
I think he just took for granted that it couldn't be intuitively justified, that it wasn't self-evident.
I took I think he just took for granted that sensation wasn't going to ground it and he just went straight for the two types of argument,
demonstrative and probable. Whereas in the inquiry he dealt with those four different sources.
Now what I'm going to do now is look at the logic of the argument, trying to sort of analyse it in terms of its bare logical bones.
So my claim is that the argument can be represented using pretty much a single relation, the founded on relation with these various relator.
So we've got probable inference, causal reasoning, experience, uniformity principle.
That's the principle of extrapolation from past of future.
We've got reason, demonstration, intuition and sensation.
So here we have a formal representation of the argument, as I've just described it.
So we have at the top there Hume's claim, the probable reasoning that is reasoning from the observed to the unobserved all depends on causation.
And we've seen how he argues that. Below that, we've got the claim that all knowledge of causation arises from experience.
And he draws the conclusion that all probable inference, all inference to anything unobserved has to depend on experience.
Okay. We then have that any inference from experience has to be based on a principle of extrapolation.
What I call the uniformity principle, the principle that the future will be uniform with the past.
So again, since probable inference is is founded on experience, since we can only infer anything from experience by founding,
that's on the uniformity principle, it follows that any probable inference has to depend on the uniformity principle.
Okay. Now we get to the heart of the argument. We have, but any probable inference is founded on the uniformity principle.
It follows then that you cannot further uniformity principle by probable reasoning
if inference from observed to unobserved depends on the uniformity principle.
It follows that you cannot use such inference to ground the belief in the uniformity principle.
But the uniformity principle cannot be founded on demonstrative arguments either.
Nor can it be founded on intuition, nor can it be founded on sensation.
Therefore, HUME concludes, it cannot be founded on reason.
And if. The all probable inference depends on the uniformity principle.
And the uniformity principle cannot be founded on reason. It follows that probable inference cannot be founded on reason.
Okay, so that's the structure of the argument as it appears in the inquiry.
My suggestion is that in the treaties these two bits are missing.
But other than that, the logic of the argument, I think is very similar.
Now, this isn't very apparent when you look at the text of the treaties.
The reason it's not apparent when you look at the text of the treaties is that HUME doesn't
simplify things at the beginning of the argument in the same way as he does in the treaties.
What happens is he starts off talking about the inference from the impression to the idea.
We've seen how that fits into the pattern of the treaties that he's taught.
He started talking about the impressions of the senses and memory.
He's now moving on to talk about the inference from the impressions of the senses or memory to an idea of something as yet unobserved.
The inference from the impression to the idea and at the beginning of one, three, six, that's his focus.
Then he says, Well, any such inference is going to have to depend on this supposition of uniformity,
but the course of nature continues, always uniformly the same. And the things we have not observed must resemble those we have observed.
And then he asks, What is the basis for that?
And it's only then that he even mentions probability.
He says, well, let's look at demonstration probability, see whether either of those conform to this principle.
Now because the beginning of the argument was all about the inference from the impression to the idea,
and he's only just mentioned probable reasoning.
He now has to run through the argument showing that probable reasoning depends on the uniformity principle.
He's already said that the inference from the impression to the idea depends on the uniformity principle.
But he has to repeat that argument when talking about probable reasoning.
So we get an extra epicycles in the argument. It's that bit more complicated.
And on the diagram, you'll see. At the bottom of stage three there what I have called stages i, j and K.
Those add that extra complication. Whereas in the inquiry.
HUME Right from the start, he's talking about probable reasoning inference from observed to unobserved.
And therefore, he when he comes to talk about the basis of the uniformity principle, he can very,
very smoothly move from saying the probable inference is founded on the uniformity principle.
Therefore, trying to find the found the uniformity principle on probable reasoning would be evidently going in a circle and taking that for granted,
which is the very point in question. So I'm suggesting that the argument in the treaties is in this respect more complicated.
And. In this respect, it's less complete.
But I think essentially it's very similar.
The overall thrust of it is, I think, exactly the same.
Now. At about the same time as HUME was working on the inquiry, he was writing the letter from a gentleman, which we've already come across.
And I just want to point out how well the logic that I've just pointed out fits with that.
We have HUME denying that the uniformity principle can be based on sensation or intuition or demonstration or probability.
And he uses that to conclude that it can't be founded on reason.
And then if we look at the letter from a gentleman, we get.
It is common for philosophers to distinguish the kinds of evidence into intuitive, demonstrative, sensible and moral.
Moral, of course. Meaning probable. So what we have here is HUME in 1745 saying there are four commonly accepted types of evidence.
And we have. HUME in 1748 producing an argument which ought which says, in effect,
the uniformity principle on which all probable inference is based cannot be founded on any of these four types of evidence.
So that seems to imply that the argument concerning induction is sceptical.
He starts by showing that all probable inference is founded on the uniformity principle.
He undermines every kind of evidence you could have for the uniformity principle.
He draws the conclusion that probable inference is not founded on reason.
That looks like a sceptical result and it's the sceptical result for which HUME is most famous.
We'll go on to discuss that in more detail next time and to look at the implications of it.
Thank you. Okay.
So we've looked at Hume's argument concerning induction from a high level perspective,
focusing on the version in the inquiry, which is the most polished of the three versions and the fullest.
But now I'm going to go back and look at Treatise one, three six, which is where the argument first occurs.
And we're going to take a closer look at that and see how it's structured and where it leads.
So let's first of all, recall how HUME got here.
He's trying to understand our idea of necessary connection in order to understand that as a component of our idea of a cause.
And that leads him to ask why we conclude that particular causes must necessarily
have particular effects and why we form an inference from one to another.
If you remember, he goes by this rather circuitous route looking at the causal maxim and then turns in this direction.
Now the key part of the process, the inference, the he calls the inference from the impression to the idea,
I'm going to use the term causal inference sometimes a shorthand for that.
Okay. So HUME starts by arguing that causal inference cannot be a priori because we can always conceive things coming out differently.
Whenever we have A followed by B and we infer B from A, we can quite easily conceive A not being followed by B, so therefore the can't be.
HUME concludes an a priori connection between the two. He seems to be making the the assumption here a common assumption common even
in our day that any a priori inference would have to yield complete certainty.
So if we can't be certain that a will be followed by B, it follows that the connection can't be a priori.
It follows then that when we infer an effect from the cause, that has to be based on experience.
What kind of experience? Well, the relevant kind of experience, HUME says, is repeated patterns of one thing followed by another.
I'm going to call those and be without any father ceremony.
When we've observed this repetition, we call the one cause and the other effect and infer the existence of the one from that of the other.
Thus, we have discovered a new relation betwixt cause and effect when we least expected it.
This relation is their constant conjunction. So we have this idea that we've gone round these neighbouring fields.
We've been looking at the causal maxim and now at causal inference.
And lo and behold, a surprise. We found the key to a necessary connection.
Now, if you remember that passage back in one 3211 when HUME said contiguity and priority are not enough.
There is a necessary connection to be taken into account. He capitalises necessary connection.
Now, in this passage I've just quoted, he capitalised this constant conjunction,
and the text also makes very clear that this is harking back to that earlier passage.
Contiguity and succession are not sufficient to make us pronounce any two objects to
be cause and effect unless these two relations are preserved in several instances.
That is, there's a constant conjunction between them.
So it's very clear that humans here identifying constant conjunction as the key to that elusive component of necessary connection.
But we still got a question of how that comes about.
How is it that constant conjunction gives rise to this elusive idea?
Well, perhaps it will appear in the end that the necessary connection depends on the
inference instead of the inferences depending on the necessary connection.
So he was just going to go ahead, talk more about the inference and how that works.
And perhaps who knows? We'll find in the end that sorting out how the inference works will give the key to the origin of that idea.
Okay. So we've got causal inference from cause A to effect B,
we've established that it's based it must be based on past experience because it can't be a priori.
And the relevant experience is memory of constant conjunctions.
The next question is whether experience produces the idea.
That's the idea of the effect that we're inferring by means of the understanding or imagination,
whether we are determined by reason to make the transition or by a certain association and relation of perceptions.
Now notice in this passage I've highlighted three of the words.
Understanding, imagination, reason. It's absolutely clear that reason is here being used as a synonym for understanding.
And notice this instead of having another synonym for imagination, he talks about a certain association and relation of perceptions.
So it's clear that if the inference turns out to be due to association of ideas, Hume's going to attribute it to the imagination as opposed to reason.
And here, the key question of this section is posed as which faculty is responsible.
Now, in an earlier lecture, we looked at Hume's faculty theory.
We're going to be coming back to that when we discuss human scepticism.
But notice, crucially, that that plays the major role here.
So what Hume's now going to do is argue that reason cannot be responsible for the inference, and that leaves the imagination.
Okay. So if reason determine this to make causal inferences,
HUME says it would proceed upon that principle that instances of which we have had no experience must resemble those of which we have had experience,
and that the course of nature continues, always uniformly the same.
Now that's commonly called Hume's uniformity principle, or UAP.
He doesn't call it that. But many people since Stroud, I think, have done so.
Now notice that it seems to be expressed as a conditional it saying if a reason is involved, then it must be based on this principle of uniformity.
Notice also that the principle seems very implausible.
It's it's too strong. It seems to say.
But the course of nature continues always uniformly.
The same instances of which we've had no experience must resemble those we have experienced.
That's more than we want. We don't want to say that everything in the future is going to be just like it was in the past.
Sure, we're going to expect the same general laws to apply, but we don't expect precise repetition.
Now in both of those respects, we get a significant contrast in the version in the inquiry.
So he says things like this all our experimental conclusions, in other words,
conclusions from experience proceed upon the supposition that the future will be conformable to the past, all of them.
Whenever we make such an inference, we're proceeding on that supposition.
We're taking for granted the uniformity principle. Now, there's no hint of a conditional here.
It's not. If reason determined us, then we would be applying the uniformity principle.
We are apparently applying it in all reasonings from experience.
There is a step taken by the mind, the inference from past a future.
Notice also that in the inquiry the uniformity principle is much vaguer than the one in the treaties, and that means it is less open to refutation.
It's actually better. It's talking about the future being conformable to the past, resembling the past.
We take the past as a rule for the future. Now.
Importantly, HUME is not suggesting, even in the inquiry,
where it seems that he's saying that the uniformity principle is always applied in inductive inference.
He's not saying that we think of the uniformity principle explicitly when we make inductive inferences.
Rather, I think the best interpretation here is that when we make an inductive inference, we manifest confidence in the uniformity principle.
We are basing our predictions for the future on the past.
And in doing so, we do in fact take the past as a rule for the future.
So the question arises, can this assumption,
this assumption that the past can legitimately be taken as a rule for the future, cannot be based on reason?
Or is there some other explanation for why we do it?
Well in what follows. We need to be aware that there are two types of argument within the standard LOCKEAN framework.
We have demonstrative reasoning and probable reasoning.
Demonstrative reasoning what we now call deductive reasoning yields knowledge in the strict sense, in the sense in which HUME uses it in treaties.
One. Three. And the demonstrative inference is made up of links that are intuitively certain that are self-evident.
So imagine a mathematical proof consisting of a number of steps, and each step is one that you can just see to clearly be valid.
The each step follows absolutely obviously from the one before.
And a chain of such inference constitutes a demonstrative argument.
And in the case of a demonstrative argument, you can be quite sure if the premise is true, the conclusion will have to be true as well.
Now, probable inference isn't so certain.
Some links in that inferential chain and probable inference are themselves only probable.
When you read the arguments in the inquiry, be aware that HUME uses a number of different words for this kind of inference.
He calls it moral reasoning or reasoning concerning matter of fact and existence.
That's pretty close to at least many modern uses of the word induction.
I'm not going to argue the case now, but I think it is pretty clear that when HUME talks about demonstration,
it's more or less the same as deduction in the informal sense,
not in not formal deduction, but in the informal sense where we take an argument to be deductively valid if it's
not possible for the premises to be true and the conclusion false at the same time.
Okay. So HUME has just stated the uniformity principle in the Treaties.
And without any further ado, he says, Let us consider all the arguments upon which this principle may be supposed to be founded.
These must be derived either from knowledge or probability, and he is clearly using knowledge here to mean demonstration,
because he immediately goes on to make the point that no demonstrative argument can do the job.
You cannot demonstrably prove that the future will conform to the past because we can easily conceive it non-conforming.
That's enough to show that it can't be demonstrably proved.
What about probable reasoning? Can we use probable reasoning to argue in favour of the uniformity principle?
Well, no, we can't. Why not? Because probable reasoning must be causal.
Humans made the point that all inference from experience depends on the relation of cause and effect.
Uh, we only know about cause and effect by experience.
All inference from experience requires the uniformity principle.
So trying to use that kind of inference to justify the uniformity principle is going in a circle.
So neither demonstration nor probable reasoning can lead to the uniformity principle.
And HUME immediately concludes that therefore, the uniformity principle is not founded on reason.
Now I just want to point out that there is quite an important gap in Hume's argument.
He's arguing that the uniformity principle can't be founded on the demonstrative argument.
Because a change in the course of nature is possible. We can conceive of things not going on as they have in the past.
That's enough to show that we can't demonstrate from what's happened in the past that the same thing will happen in the future.
The mere possibility that things could turn out wrong scuppers the chance of any demonstrative argument.
What about probable inference?
Well, we can't use a probable inference because any probable inference, HUME says, must depend on experience and any argument from experience.
Ipso facto, requires the uniformity principle. Okay.
But just suppose there was a mode of reasoning that was less than demonstrative,
that was merely probable, but was a priori that did not depend on experience.
So you might think of some kind of statistical or probabilistic inference if there were such a form of inference available.
HUME would not have anticipated it. He is taking for granted that all probable inference depends on experience.
So there is a potential gap there, which quite a number of scholars and John Mackey, for example, Simon Blackburn, Roy Harrod have tried.
To work through. They have tried to exploit that gap to give an answer to humans apparently sceptical argument.
So let's look at Hume's conclusion. Thus not only reason fails us in the discovery of discovery of the ultimate connection of causes and effects.
Okay. We can't discover causes and effects a priori i.
But even after experience has informed us of their constant conjunction,
it is impossible for us to satisfy ourselves by our reason why we should extend that
experience beyond those particular instances which have fallen under our observation,
we suppose, but are never able to prove that there must be a resemblance between those objects of
which we have had experience and those which lie beyond the reach of our discovery.
Now I've put a question mark after the word sceptical.
It looks like a sceptical conclusion.
We saw before that the structure of the argument, especially in the inquiry, makes it look like a sceptical conclusion.
He's saying all this inference relies on the uniformity principle and then he's knocking
away all the various supports that the uniformity principle might have in the treaties.
He's taking for granted that the only two possible supports are demonstrative and probable reasoning in the inquiry.
He's also knocking away intuition and sensation.
So it looks like a sceptical argument. But when we come back to consider the nature of Hume's scepticism later, we'll see that that's not so clear.
At any rate, where we are in the treaties. Hume's main business is to sort out the nature of causal inference and the nature of the idea of cause.
He's shown that reason can't explain inductive inference,
and he concludes that instead it must arise from the associative principles of the imagination.
Remember, he's identified three associative principles uh, contiguity, resemblance and causation.
And he's saying that similar kinds of principles are at work when we make causal inferences.
Now notice that the kind of association at work here isn't quite the same as ordinary causal association.
I mean, suppose, for example, I look at a picture and it makes me think of the artist.
That's a causal association, an association of ideas.
But it's not this kind of causal inference. It's not seeing a cause and inferring an unseen effect.
Okay, it's a different thing. HUME does sometimes confuse the two,
but I think there's a fundamental difference between the kind of association of ideas that you get with resemblance and contiguity and causation.
Between that and causal inference where you infer something unknown, you don't simply associate ideas.
HUME calls this associative process custom. And he says he's not by calling it custom.
All he means is that it is a habitual process.
It's the kind of process we identify as customary.
You see A followed by B, you get used to A following B that start B following A and then you see and
I and you invariably that's just the kind of thing we call habit or custom.
Now notice that his attitude to it is not as you might expect.
Negative custom, then, is the great guide of human life.
It is that principle alone which renders our experience useful to us.
That's rather an echo of Joseph Butler, who said Probability is the guide of life.
Here we have HUME saying Custom is the great guide of life. That's from the inquiry.
But he makes a very similar comment in the abstract, which was probably written about ten months after the treatise was published.
He knew the end of the section 136. He says that this is essentially the same kind of custom as that which explained general ideas.
You remember his theory of general or abstract ideas. He appeals to the idea of a customary association between a word and a revival set of ideas.
So here he is finding another key use for the same principle.
The custom is an absolutely central thrust in his philosophy.