Hume concludes bluntly (p. 28) that "All inferences from experience ... are effects of custom, not of reasoning." Thus we are justified in expecting the sun to rise tomorrow, though only by habit or custom -- it is not a proposition supported by reason. This seems a very strange claim.

Has he simply defined reason too narrowly, to include only deductive inference? We are tempted to say that it is an inductive inference, which we believe to the degree of certainty that the evidence (our past experience, reports of others) warrants -- and that the weight of probability is very heavy in this case. Given our individual and collective experience and known history (including geologic history), the sun will rise tomorrow to a near certainty, we want to say, and inductive reason strongly warrants our belief that it will.

But Hume might reply that we have only made the proposition seem highly probable by artificially excluding myriad other possibilities of which we have no knowledge. We don't know what we don't know, so we cannot accurately factor in all possibilities to calculate the genuine liklihood of its occurring. Thus the probability calculation we used to justify the belief is not meaningful data after all.

Hume's Enquiry poses a very radical skeptical problem: We are inclined to accept his premise that all our simple ideas come from impressions (feelings, perceptions), and that all other thoughts are memories or recombinations of these. It also seems fair to say that our understanding of matters of fact depends crucially on relations of cause and effect. However, we cannot discover causal relationships in our impressions -- no matter how hard we try, the best we can get is a constant conjunction of events that we infer (rather than perceive) to be causally related. It seems to follow that we have no direct perception of causality, and hence no knowledge of it as such. But if we never know about causal relationships, can we really be said to know much of anything about the world of our experience (other than the bare fact that we experience it)?

Hume on Moral Philosophy

As the editor (Eric Steinberg) notes on page 1, Hume uses the term 'moral' in the Enquiry in three senses. The first and broadest, pertaining to human nature, he shares with most philosophical usage of his own and the previous century. The second and more specific, the study of obligations, ethics, rights, right and wrong behavior and the like, is our most common sense of the term today. The third is interesting because it suggests something specific about Hume's own philosophical view: In this usage he contrasts "moral" in the sense of something based on experience or matters of fact with things that are "demonstrative" (by which I take it he means logically inferential) or "intuitive" (the way, for example, he thinks we intuit causal relationships rather than perceiving them).

It is worth wondering a little, I suspect, about this third usage.

Welcome

Welcome to Skeptiblog, a discussion space for my philosophy/honors seminar on Hume and the Skeptics. Others are welcome to read and comment as well, of course, while observing basic netiquette.