Hume Studies

Every interpreter of Hume is compelled to grapple at some point with the problem of the relationship between Hume’s Treatise of Human Nature (1739) and his two enquiries: An Enquiry concerning Human Understanding (1748) and An Enquiry concerning the Principles of Morals (1751). Readers are often guided in this area by Hume’s own later reflections and directions to his readers, particularly by the witty, but terse comments in “My Own Life,” where Hume acknowledges his youthful disappointment when the Treatise “fell dead-born from the press, without reaching such distinction, as even to excite a murmur among the zealots,” and then reports a longstanding conviction that his literary failure with the Treatise “had proceeded more from the manner than the matter.” This famous self-assessment suggests the relationship between the earlier work and the later ones is more a matter of style, exposition, and clarity than of differences in philosophical substance. Close readers of the Treatise and the two Enquiries, however, have often found a significantly more perplexing and far less straightforward relationship among these works.

Hsueh M. Qu’s delightful and thought-provoking Hume’s Epistemological Evolution is the first book-length treatment of the relationship between Book 1 of the Treatise of Human Nature and the Enquiry concerning Human Understanding. Qu’s book ties together many of the strands of earlier commentary on the subject, synthesizes and critiques them, and develops its own comprehensive and original interpretation. The style is precise and detailed, yet easygoing and fluent, and the book will no doubt serve as the starting point and benchmark for future research on its subject for many years.

One important general theme of Qu’s interpretation is the contention that in Book 1 of the Treatise, epistemological issues take a backseat to psychological issues, and epistemological issues tend to arise in the earlier work as “offshoots” of psychological ones, whereas the focus of the Enquiry is much more epistemological. More controversially, Qu rejects the view that the philosophical differences between the Treatise and the Enquiry are only differences in manner, not matter. He argues that Hume disavowed the Treatise treatment of skepticism “because of his dissatisfaction with the response to scepticism offered in the former work: he finds the Treatise’s epistemological framework to be philosophically inadequate” (Qu, 1). Qu believes that Hume defends mitigated skepticism in both the Treatise and the Enquiry, so “his final position is indeed the same in both works.” However, he also argues that the “arguments and frameworks” that lead to this position differ between the two [End Page 183] works, with the Treatise offering defective arguments for this “same philosophical endpoint” (12).

As a preliminary step toward justifying his contention that the Enquiry is more normatively focused than the Treatise, Qu begins by comparing and contrasting the stated aims of the two works, as set out in the Treatise’s “Introduction” and in EHU part 1. The most important difference he finds is the emphasis in EHU part 1 on the project of driving out false metaphysics. While the Treatise is focused on establishing a psychological science of man, the Enquiry, “in emphasising its aim of driving off a class of poorly justified beliefs . . . seems more self-consciously normative than the characterisation of the aims of the Treatise in the corresponding section of that work” (42). In the Enquiry, as Qu reads it, the epistemological recommendations delivered haphazardly and parenthetically in the Treatise have been elevated into a fundamental purpose of the work.

Moving from overview to detail, Qu takes up the problem of Hume’s views on induction in Chapters 3 and 4. He follows Stroud in distinguishing a negative phase from a positive phase in Hume’s argument on induction, the first phase aiming to show that inductive inferences are not founded on reason, and the second aiming at the conclusion that they are instead determined by custom. That these two phases of the argument can be found in both the Treatise and the Enquiry is a...