Although the topic of section VIII seems close to that of §VII in the context of the Enquiry, the corresponding discussion in Hume’s Treatise appeared not in the 1st book, the treatment of the “understanding” where he addresses the topics of the earlier sections (as well as of those later sections that correspond to material in the Treatise), but instead as part of his discussion of the will of the 2nd book of the Treatise, which is devoted to the “passions.” (The third book is devoted to “morals,” and Hume reworked its content in another later work, An Enquiry Concerning the Principles of Morals. Most of the 2nd book of the Treatise was addressed later only in a short work, “A Dissertation on the Passions.”)

The section is divided into two very unequal parts. The first (pp. 53-64) is mainly devoted to the implications of Hume’s account of cause and effect for the explanation of human actions; but, near the end, he considers the sort of freedom of the will, what he calls “liberty,” that would be consistent with this view. The second part (pp. 64-69) is devoted mainly to the implications for morality of his view of the freedom of the will. You should notice especially the objection he considers at the end (pp. 66-69): it should give some indication of what Hume would have to say about the view of human freedom you saw in Leibniz.