This section is perhaps the most important in the book. Here Hume begins his discussion of the relation of cause and effect, and it is in his views on this relation that he has had his greatest influence. He will continue discussing cause and effect in later sections, but his “skeptical doubts,” and especially the argument for them that he presents in this section, are at the heart of this discussion.
• The distinction between “relations of ideas” and “matters of fact” that he makes at the beginning will play an important part in this argument. It is not unlike distinctions you’ve already encountered, especially Leibniz’ distinction between “truths of reasoning” and “truths of fact” in the Monadology, §33.
• The basis of Hume’s skeptical argument appear in the discussion of the sources of our knowledge of cause and effect on pp. 17-19 of part I, but he doesn’t draw any really skeptical conclusions at this point.
• The real core of the skeptical argument appears in part II on pp. 21-24 in Hume’s argument that our conclusions regarding causes and effects “are not founded on reasoning” and, in particular, on the specific form this argument takes. So pay close attention to that and, especially, to the circularity he claims in the paragraph beginning at the end of p. 22.
• The discussion of children in the last paragraph of the section serves here only to bolster Hume’s argument, but it is closely tied to the “solution” to these skeptical doubts that he will suggest in the next section.