I am asked to write an essay with the following prompt:
Hume claims all of our reasoning concerning matters of fact is ultimately dependent on the idea of cause and effect. Why does this pose an epistemological problem, and what is Hume’s “skeptical solution” to that problem?
The response should be based on section IV and V in An Enquiry Concerning Human Understanding. Could you please tell me the answers to the questions and evidence in the text to corroborate the thesis?
In Section IV of Hume's An Enquiry Concerning Human Understanding (1748), Hume argues that knowledge is divided into only two categories--the relation of ideas and matters of fact. The first category can be understood through the exercise of intellect:
Propositions of this kind are discoverable by the mere operation of thought, without dependence on what is anywhere existent in the universe. (Section IV, Part 1)
The second category--matters of fact--relies not on the "operation of thought" but on the relationship between cause and effect, and Hume uses as one example of this relationship a man on a deserted island who comes across a pocket watch buried in the sand. He concludes, because he recognizes the object and knows it to be man-made, that man has been on the island--the cause he recognizes to be man's earlier presence on the island, and the effect is the watch he is holding. Cause and effect are in unalterable lockstep. Hume concludes that all matters of fact are understood this way. Hume goes a bit further by arguing
that the knowledge of this relation is not, in any instance, attained by reasonings a priori; but arises entirely from experience, when we find that any particular objects are constantly conjoined with each other.
In other words, the cause-and-effect relationship is not understand by the "operation of thought" but by understanding that a perceived effect has to have a directly related cause.
As good as an empirical proposition as this is, however, it has a flaw from an epistemological standpoint. Using his own example of man who finds a watch on a desert island and then "knows" that man has been there before, one could argue that, in this example, cause and effect is likely to lead to errors in knowing. Let us suppose, for example, that a shipwreck occurred far out to sea and the pocket watch somehow made it to shore without human intervention. The effect is the same, but the cause is very different, thereby rendering the conclusion completely different. In other words, the relationship between cause and effect is dependent upon understanding the cause, not the effect, and knowing a matter of fact is not solely dependent upon recognizing that there is a relationship between cause and effect. Perhaps even more important, Hume's argument in Part II that the truth derived from understanding the relationship between cause and effect is based on experience is only true if our experience leads us to the one correct conclusion. To be fair, to Hume, however, he concludes the "Doubts" section by his caveat that
To endeavour, therefore, the proof of this last supposition by probable arguments, or arguments regarding existence, must be evidently going in a circle, and taking that for granted, which is the very point in question.
Hume's doubts, then, lead him to the conclusion that the validity of the cause-and-effect argument is based on the perhaps faulty supposition "that the future will be conformable to the past."
Hume attempts to resolve his doubts in Section V, Part I, by arguing that, even without vast experience, one can (1) understand the relationship between cause and effect and (2) know matters of fact (again, even without much experience) simply through the operation of Custom or Habit, which he describes thus:
For wherever the repetition of any particular act or operation produces a propensity to renew the same act or operation, without being impelled by any reasoning or process of the understanding, we always say, that this propensity is the effect of Custom. (Section V, Part 1)
Simply put, if one action repeatedly leads to a repetition of that action (and this must be observable rather than reasoned out), this repetitive action becomes "Custom or Habit," and this repetitive action or operation, because it is not dependent on the "operation of thought" becomes a matter of fact, observable through some level of experience. In other words, as opposed to knowing something because we understand the relationship between cause and effect, we know something because we understand that custom or habit dictates a particular result--and, as Hume concludes,
Without the influence of custom, we should be entirely ignorant of every matter of fact beyond what is immediately present to the memory and senses. (Section V, Part 1)
Custom or habit, then, is a source of matter-of-fact knowledge and, in a real sense, replaces the necessity of understanding, through individual experience, an understanding of the relationship between cause and effect. Knowledge of matters of fact is still based on observable experience but does not require the amount of experience that an understanding of cause-and-effect relationships does.
I think it's important to point out that like all empiricists, Hume argued that all knowledge is at least ultimately derived from experience. So even though he does distinguish between matters of fact and relations of ideas, all ideas are ultimately derived from matters of fact. The problem of causation arises because the relationship of cause and effect can not be experienced - all we experience is a succession of events - and it also cannot be inferred. To infer causation from experience is to presume the uniformity of nature, namely that because I have experienced the succession of events a and b in the past (perhaps many times or even every time), the same succession of events will occur in the future, so that we can say that event a causes event b.