In these sections, Hume is again mainly concerned with the relation of cause and effect and adds further elements to his account of it, which he will not complete until section VII.
• The moral of the whole of section V could be taken to be Hume’s remark in ¶6 (p. 29) that custom is “the great guide of human life.” And the application of this idea to cause and effect can be found in the conclusion stated in ¶8 (p. 30). Be sure you understand the relation he sees between belief and “customary” or “constant” conjunction.
• Although Hume gives readers without a taste for the “abstract sciences” leave to stop after part I of §V, you will, of course, continue to part II to see him give a more detailed account of belief and the way it is affected by habit or custom. Hume would take the term “belief” to apply in cases pretty much the same as those in which Descartes would speak of “judgment,” so you should compare what Hume says about belief and the will (in ¶11, p. 31) with what Descartes said in Meditation 4. Who do you think is closer to the truth?
• The ideas about probability in §VI agree pretty well with those in the Treatise bk. 1, pt. 3, §§11-12, and the latter were written less than 50 years after Locke’s Essay was published. There had clearly been a sea change in thinking about probability in the meantime. While Locke thought of it mainly as a measure of the credibility of testimony, Hume is not merely aware of an association with the mathematical theory of chances: he takes that for granted. Note how, at the end of the section, he tries to fit his account of probability in this sense with his account of cause and effect.
Hume’s title for §V has captured the imagination of philosophers in ways that are independent of his specific account of cause and effect. After you’ve thought about that account, go back to what he says about “skeptical philosophy” at the beginning of §V and think what he might have in mind when he speak of a skeptical solution to skeptical doubt. Thinks also how this compares to Descartes’ way of dealing with skeptical doubt.