What are Hume's views on causation? Can they be improved?
The question 'Why?' is at the root of all philosophy. This question is put in other words as 'What is the cause of x?' This shows the importance of the idea of causation to philosophy. Despite its important place in reason and general philosophy, it is rare that a philosopher questions this concept. David Hume, on the hand does so. He accepts the challenge of taking issue with this so vital a concept. Hume finds causation to be one of seven different kinds of relation between objects. From examining the differences between these relations, he finds causation to be a special case - it is the only relation between objects or ideas which requires the use of reason, and is independent of the idea itself. He then launches into an investigation into what actually makes something a cause - what is necessary for something to be accurately referred to as a cause.
Firstly he sees whether the claim that causation is 'intuitive' is a valid one. Upon closely scrutiny, it appears that this concept is not intuitive at all. Hume claims that intuition is based on sense perception. This rules out any form of innate or a priori knowledge. This question will be given closer scrutiny below, but for now we shall allow Hume to make the assertion. It is impossible to conceive of cause and effect from sense perception alone. Take any set of sense data at any one instant of time, and there can be no possible indication of causation. Even allowing for the use of memory to expand the group of sense perception, without the use of reason it is not possible to have any idea of causation. As reason is required to find causation, then it can not be purely intuitive, that is, based on sense perception. Also, it is impossible to disprove the potentiality of an uncaused object, without already having proven that every object has a cause. Since it is not possible to prove that every object has a cause until the idea of causation has been established, it is pre-emptive to say that uncaused objects are impossible. As it can not be said that an uncaused object is impossible, then this is further evidence that causation is not intuitive. Hume uses this argument to show how philosophers prior to him had used circular arguments to assert the universality and consistency of causation - there can be no uncaused object, because every object must have a cause.
Hume concludes from this that the idea of causation must be derived through experience. He then begins to look at causation as a relation between objects, in order to try and establish what is required for an object to be a cause. His first discovery is that although it is often the case that distant objects - objects separated by distance and time etc - are seen as joined by cause and effect. Hume claims that although this may seem the case, what actually happens is that there is a chain of objects and events, one causing the next, which links the two distant objects. The thought that the two distant objects are directly cause and effect is just a simplification for the convenience of the mind. Therefore, the first criterion for causation which Hume lights upon is that of closeness, or contiguity.
The next assertion, although more controversial, is that the cause must precede the effect. There is a body of opinion who dispute this, but Hume argues that this must be the case as such. It is impossible for a cause and its effect to be co-temporal (or of the same time), because if this is the case for one event, then it must be the same for all, thus annihilating time. This must be the case because, if one cause takes more than no time to create its effect, it is essentially distorting time and thus makes no sense in the hypothetical co-temporal universe. It is therefore impossible, in this universe that an effect could be co-temporal with its cause for it could be so, then it would destroy our conception of time. Hume concludes that succession must also be a criterion of causation.
At this point in his argument, Hume claims to have exhausted his analysis of causation as a relation between objects, yet has not arrived at sufficient idea of causation. It is easily possible, and indeed in most cases it is true, that two objects may be contiguous and succeed from one another, yet the prior object is not the cause, nor the latter object the effect. Hume now turns to experience to help find his 'necessary connexion' between cause and effect. He asks how an initial impression can change into an idea of a connected cause and effect, and then wishes to examine the nature of that idea. Firstly, Hume explains his position on objects and ideas, and states,
'As to these impressions, which arise from the senses, their ultimate cause is, in my opinion, perfectly inexplicable by human reason, and 'twill always be impossible to decide with certainty, whether they arise immediately from the object, or are produced by the creative power of the mind, or are derived from the author of being.'Hume does not let this stop his analysis of perceptions, and goes on to say that even though we can not be sure of the origins of our ideas, it is still possible to draw inferences from them.
In his search for signs of causation from our sensory experience, Hume finds that in every case of what we see as causation, there must be repetition. In other words, if two objects are seen associated by succession and contiguity on a number of occasions, then we call this causation. Hume refers to this criterion as constant conjunction. Still in this case, it can not be said that the idea of two objects related by causation has been reached by reason, only through the imagination. This idea of cause and effect is contingent on the two object always being related by succession and contiguity, with no exceptions. The idea of causation at which Hume has now arrived, is actually very consistent with what we experience in reality. This can be seen by the example of the history of science - science has seen various things as causes, until it is found that another solution provides a more accurate answer. In other words, things can be called causes until they are disproved or replaced.
As such, Hume's idea of causation does not show any positive explanation of what is causation, he only claims that in a philosophical sense, there is no reason to believe that causation is the gospel truth it has been claimed to be by past and present philosophers alike. His summary of the roots of the idea of causation is this - in a single instance, no power or connexion can be found between two objects (by 'power', Hume refers a power to cause and effect), but after many uniform instances, the mind 'feels' a notion of cause. This 'feeling of a new sentiment' towards the relation between two objects is the idea of causation. This rather weak statement is Hume's theory of causation in a nutshell, and is fully consistent with his non-committal style of scepticism. Instead of proposing a strong account of causation, Hume simply states that it is not possible to have one, and provides this much weaker and more ambiguous account.
The first improvement that could be made on Hume's philosophy of causation is to clear up a confusion which has been pointed out by subsequent philosophers. Hume seems to have two definitions of causation, one 'natural' and one 'philosophical'. Throughout his search for the connexion between objects that can be called causation, Hume never claims that there is no such thing as causation, only that the connexion or 'power' between cause and effect can not be known, apart from continuous conjunction of succession and contiguity. Hume's ideas on 'natural belief' are such that he thinks it is possible for us to have cause and effect, and to believe there is a connexion between cause and effect, but simply not know what is the essence of that connexion. This essence is the 'philosophical' definition of causation, and is not found in Hume's philosophy.
The point was made earlier that Hume's assertion that causation is not intuitive relied on there being no innate or a priori knowledge. It is, however, arguably possible that causation could be intuitive through some form of innate knowledge or capability. An argument for this case is thus. The capability to learn must logically be innate, and would most likely contain as least the very basics of reason, and most certainly contain what it is that makes human kind naturally curious. Natural curiosity can be seen in the youngest babies, in that they turn their head towards light, or reach out to an image. In slightly older children, there is shown the tendency to continuously ask 'Why?', in response to the answer to a previous question. What is this, but a desire to follow a causal chain from an assertion to something that the child will have perceived for themselves, and therefore of which they will have immediate knowledge. This desire to link objects with causation seems to be innate, and therefore intuitive.
To conclude, when examining causation, Hume arrives at a final point where , although he accepts that there is causation, claims that it is impossible to know the essence of the connexion between cause and effect. His view can be clarified by showing that he is not disallowing knowledge of causation, but only of its essence, thus allowing causation to survive. Hume is very careful in making sure his philosophy allows the survival of causation, for if he were seen to be denying causation, he would be seen to be denying everything that we could know, including the tenets of reason. His position, however, can be challenged by the proposition that there is a chance that causation could be known intuitively. Even in this case, however, the remainder of Hume's argument of causation could be said to stand, as the intuition only serves to provide the idea of Hume's 'natural' definition of causation, not the 'philosophical' definition.