Pouring New Wine Into Old Skin – Hume and the Early Wittgenstein on Induction and Causation
This paper compares Hume’s claims about induction and Causation (in both the Treatise and the Enquiry) to the prima facie similar treatment of these issues by Wittgenstein in the Tractatus (esp. 6.3-6.3751 & 5.135-5.1363). The proposition that there are no grounds for believing that the sun will rise tomorrow appears in all three texts, and always does so within strongly anti-metaphysical frameworks. However there is much controversy regarding the exact nature of these frameworks and how they relate to the proposition in question. In the case of Hume, there is the question of whether or not he held a regularity view of causation. The early Wittgenstein, by contrast, explicitly states that ‘There is no compulsion making one thing happen because another has happened. The only necessity that exists is logical necessity’ (T 6.37). The trouble, however, is that the he took most (if not all) of the propositions of the Tractatus to be nonsense. Moreover, there is much debate as to whether or not he took these nonsensical propositions to nevertheless show profound ineffable truths which cannot be said. In this paper we examine the relation between these ‘old’ and ‘new’ readings of both Hume and Wittgenstein. We conclude that whether or not Hume was a proto-Wittgensteinian depends on whether the early Wittgenstein was a Humean, though of course whether or not Wittgenstein was truly Humean (i.e. true to Hume) in turn depends on whether Hume was a proto-Wittgensteinian.
Pouring New Wine into Old Skin:
Hume and the Early Wittgenstein on Induction and Causation
1. Similarities
Looking at Wittgenstein’s remarks about induction and causation towards the end of the Tractatus one is immediately struck with a number of similarities between what Wittgenstein appears to be saying, Hume’s treatment of these topics in both the Treatise and the Enquiry. The table below illustrates some of the more obvious ones:
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Treatise and 1st Enquiry
Tractatus
T 98 Reason can never satisfy us that the existence of any one object does ever imply that of another.
______
T 88 From the mere repetition of any past impressions, even to infinity, there will never arise any new original idea, such as that of necessary connection.
______
T 183 All our reasonings concerning causes and effects are deriv'd from nothing but custom.
______
E 29 The bread, which I formerly ate, nourished me; that is, a body of such sensible qualities, was, at that time, endued with such secret powers; but does it follow that other bread must also nourish me at another time, and that like sensible qualities must always be attended with like secret powers? The consequence seems no wise necessary.
5.135 There is no possible way of making an inference from the existence of one situation to the existence of another, entirely different situation.
______
5.1361 We cannot infer the events of the future from those of the present.
There is no causal nexus to justify such an inference.
______
5.1361 Superstition is nothing but belief in the causal nexus.
______
5.136 It is clear that there are no grounds for believing that the simplest eventuality will in fact be realized.
T 6.36311 It is an hypothesis that the sun will rise tomorrow: and this means we do not know whether it will rise.
The juxtaposition of these passages highlights the similarities between the things Hume and Wittgenstein say about the relationship between the thing we take to be a cause and the thing we take to be its effect, but also the differences between the reasons they have for saying them.
2. The Will
Hume and the early Wittgenstein’s remarks about causation and induction are immediately followed with some similar looking claims about ‘the will’. We illustrate these in the table below:
Treatise and 1st Enquiry
Tractatus
T 632-3 [T]he will being consider'd as a cause , has no more a discoverable connexion with its effects, than any material cause has with its proper effect. So far from perceiving the connexion between an act of volition , and a motion of the body; 'tis allow'd that no effect is more inexplicable from the powers and essence of thought and matter.
6.373 The world is independent of my will
6.374 Even if all that we wish for were to happen, still this would only be a favour granted by fate, so to speak: for the is no logical connection between the will and the world, which would guarantee it, and the supposed physical connection itself is surely not something we could will.
Hume has just been discussing where the idea of a given cause having some special connection with its effect, in virtue of which it necessarily gives rise to that effect, could come from. He has stressed that observation of causes and effects in the world around us never gives rise to impressions of such connections. And Reason cannot help us either. Yet we still have an idea of a special connection between one event considered as a cause, and another event that follows it as effect. So where could that idea come from?
One suggestion could be this: we observe constant conjunctions between causes and effects in the world around us, but no connections in virtue of which those conjunctions are constant. But not all causes are in the world around us, some are in our worlds within. We will, and in some cases willing gives rise to action. An act of volition causes a motion of the body. This is a case of causation, and some of Hume’s contemporaries had suggested that our idea of a special connection between causes and effects observed in the outer world could have been imported from our direct experience of cases like these.
In response to this suggestion, Hume points out in the passage just quoted that there is nothing special about the will considered as a mental cause. We never perceive a connection between an act of volition and a motion of the body. In fact given the very different “powers and essence of thought and matter”, if anything the connection is even more inexplicable in this case than it is in others.
If this is the point Hume is making here, it is indeed the same point as W’s, namely, that there is nothing special about the will as a cause
But it seems to me that W’s reason for making this point is very different to Hume’s.
Hume’s point is that we never perceive a necessary connection between a cause and an effect, even when that cause is an inner cause.
W’s point by contrast, as we read in the passage quoted, is that there is no logical connection between what happens in the will and what happens in the world.
And for the Wittgenstein of TLP, (6.37): “The only necessity that exists is logical necessity”.
But what does this mean?
According to a very attractive way of reading the Tractatus, what interests Wittgenstein is logic, for which we can read in this context, the preconditions of thought.
As preconditions for thought, it is unintelligible to think that these preconditions could be otherwise. We can’t think of them being other than they are, because any thought presupposes that they are as they are.
Also in play in the Tractatus is the view that all thoughts and propositions must be bipolar. Lets treat this as a basic premise of the Tractatus that is called upon when arguing for other things, but that is never argued for itself.
Now, I said that it is unintelligible to think of the preconditions of thought as being otherwise, as not obtaining. Given bipolarity, this means that it’s not just that the preconditions of thought can’t be thought to be otherwise, but that they can’t be objects of thought at all.
If the only necessity there is is logical necessity, and given bipolarity, this means that whatever is necessary can’t be an object of thought, and whatever can be an object of thought can’t be necessary.
This is where Wittgenstein’s notorious distinction between what we can say and what must be left to show itself comes in.
This is a way of lumping all necessity together under the heading ‘must be there but can’t be put into words’.
Now, how does this relate to causation? Hume makes it sound as though we come to the world raw, as though our picture of the world is built up entirely from that which impinges on our sensory inlets and nothing else. W takes a different view.
According to him, Just as we can’t compare a process with the passage of time, but only with another process (6.3611), so we can’t measure nature except by some standard. There has to be something in place before we can say anything about the world. As a precondition for saying something about the world, this something could not be otherwise, so we can’t say what it is. Such, according to Wittgenstein, is the law of causality.
There are many things to worry us here. One of them is this: if the law of causality is such that we can’t say what it is, how come we can state it, thus: every event has a cause.
The fact is that natural languages have a structure that makes it look as though we can say this. On analysis, it will turn out that we can’t. But what we take ourselves to be able to say here, even though we can’t, really is something in the sense that it is something that can be shown, and shown in the following way:
Lots of the laws according to which we describe the world are built on a common pattern:
If water is heated to 100oC at sea level it will boil.
If a billiard ball it hit at x angle with y force, it will move off at x‘ angle with y‘ force
Etc.
As something like natural laws, these props give us a pattern on which to construct empirical propositions, which can then be tested for truth or falsity, I.e. it is a blueprint for the kinds of descriptions of the world given in mechanics. (Not the only blueprint. Our descriptions could also contain props built on other patterns. )
We can try to represent this pattern thus:
(x) x x
Which is also the pattern on which the law of causality is built. Except, for reasons too complicated to go into here, this is just nonsense. What it tries to say is shown by the fact that all of these causal laws have a form in common.
If this is the status of the law of causality, I.e. that it is shown but can’t be said, it certainly isn’t the status of most of the props we generate from it. That a billiard ball, if hit at a certain angle with a certain force, will roll off at a certain angle with a certain force, is most certainly a bipolar thought. And since all necessity is logical necessity, there can be no necessity here.
By the same token, it also isn’t the status of the law of induction, so long as the law of induction is that the future will resemble the past. So what role does the ‘so called’ law of induction play in the picture we build of the world?
This is when the Humean moment happens. No causal nexus, where causal nexus = that in virtue of which an effect follows a cause as such.
Any explanation we give has the form: every event has a cause.
Something happens. So we go out and look for a cause.
The cause we find hasn’t necessitated anything: there is only logical necessity, so all causation is accidental.
But one compelling reason why we accept an explanation is that in the past that kind of event we’re taking for a cause in this case has been correlated with the kind of event we’re taking for an effect.
And that tomorrow will resemble today is a psychological constraint we place on descriptions of nature.
This leads to belief in the so-called law of induction.
This is a Humean moment in the TLP. It makes it look as though our actual inductive practices look more like a matter of custom rather than anything else. But as we have seen, the reasoning leading up to this moment is very different in W. Whereas Hume’s was an empirical point, W’s follows from logical considerations.
I see your point Luke, but I don’t agree. You said that while Hume and Wittgenstein’s remarks on causation and induction have many superficial similarities Wittgenstein’s reasoning is not only more sophisticated than Hume’s but also so strikingly different in nature, that we might do well to view it as a criticism of Hume. Whereas Hume’s reasoning stems from the crude empiricist dogma that if we cannot observe something we cannot have any idea of it (all ideas are derived from impressions) which motivates him to start looking around for an observable causal connection, Wittgenstein is interested in conceptual and grammatical questions. It is a matter of logic that there is no causal nexus, that the Law of Causality is not a proposition with sense, that the law of induction is falsifiable, and that the world is independent of our will.
To think that any of this depending on whether or not we can observe something in an object is to miss the point.
I wish to claim that not only is this account mistaken, it is almost the inverse of what is actually going on.
Hume’s empiricism plays a superficial role in his overall argument. N doubt that Hume’s discussion takes place in empiricist terms, and this make it appear that his argument rests on an empirical generalisation, but in actual fact Hume’s point is undeniably a logical one:
T 98 Reason can never satisfy us that the existence of any one object does ever imply that of another.
E 30 Is there any more intelligible proposition than to affirm, that all the trees will flourish in December and January, and decay in May and June? Now whatever is intelligible, and can be distinctly conceived, implies no contradiction, and can never be proved false by any demonstrative argument or abstract reasoning a priori. ..It implies no contradiction that the course of nature may change, and that an object , seemingly like those which we have experienced, may be attended with different or contrary effects. May I not clearly and distinct conceive that a body falling from the clouds, and which in all other respects resembles snow, has yet the taste of salt or feels fire?