There is a very great deal more of interest and importance in Book I of the Treatise, including a fascinating section “Of Personal Identity” that is worth a tutorial all its own. But there are limits to how far I can carry this disquisition on Hume’s philosophy, and there are hundreds and hundreds of pages to go, so I shall move on to Books II and III. Perhaps I can close this discussion of Book I, which ranks as one of the truly great works of philosophy in the English language, by simply quoting a remark made by Hume, almost in passing, in the Conclusion to the Book. “Generally speaking,” Hume writes, “the errors in religion are dangerous; those in philosophy only ridiculous.” In these troubled times, when the victories of the Enlightenment seem in danger of being reversed, we might do well to reflect on Hume’s wise observation.
Books II and III, though they comprise another 390 pages, call for a good deal less in the way of commentary. Book II is entitled, “OF THE PASSIONS,” and is divided into three Parts: “Of pride and humility,” “Of love and hatred,” and “Of the will and direct passions.” Only the first two sections of Part III, “Of liberty and necessity” and “The same subject continu’d,” deserve extended discussion. But like a number of his contemporaries, Hume was a shrewd and unillusioned observer of la comedie humaine, and many of his comments about human foibles, frailties, and attitudes retain today the charm they must have possessed for their original readers [although not, alas, for the early reviewers.] There was a time when such reflections on human behavior were considered an appropriate employment for philosophers, but the practice has fallen into disuse, and today it is op ed columnists and such like lowlifes who have taken over the task of anatomizing humanity. It is a pity, I think, but there it is.
Before turning to Hume’s important discussion of freedom of the will, I will indulge myself a bit by commenting briefly on the last two sections of Part Two of Book Two, which are called, respectively, “Of the amorous passion, or love betwixt the sexes” [which runs a mere three pages], and “Of the love and hatred of animals” [which occupies two]. Hume, who was of course a bachelor, and is not known to have ever entered into an “amorous” relationship, takes a rather sunny view of sexuality. “ ‘Tis plain, that this affection, in its most natural state, is deriv’d from the conjunction of three different impressions or passions, viz. The pleasing sensation arising from beauty; the bodily appetite for generation; and a generous kindness or good-will.”
“The appetite for generation,” he goes on, “… is evidently of the pleasant kind, and has a strong connexion with all the agreeable emotions. Joy, mirth, vanity, and kindness are incentives to this desire; as well as music, dancing, wine, and good cheer. On the other hand, melancholy, poverty, humility are destructive of it.”
Alas, Hume never encountered Woody Allen.
Hume concludes, rather surprisingly, by suggesting that the passions he has just finished analyzing in humans manifest themselves equally in animals. As he says, “Every thing is conducted by springs and principles, which are not peculiar to man, or any one species of animals.” Presumably, although he does not say so, dogs, like humans, form habits of association from the observation of constant conjunctions of resembling instances, and hence, like us, have causal beliefs. They, too, believe that objects continue to exist when not perceived, as anyone can attest who has seen a dog searching for a bone it has buried. As Hume presents these ideas, they are amusing and piquante, but they are actually a legitimate part of a thoroughly anti-rational, naturalized conception of human nature that has much more in common with modern neurology and behavioral psychology than it does with the long Western tradition of rationalist philosophy.
The same mode of understanding human behavior is manifest in Hume’s discussion of that old reliable philosophical debating topic, freedom of the will. Getting a bit ahead of ourselves, we might say somewhat anachronistically that in this debate, Hume sides with Hobbes rather than with Kant. Hume begins by stating flatly that “by the will, I mean nothing but the internal impression we feel and are conscious of, when we knowingly give rise to any new motion of our body, or new perception of our mind.” It is instructive to compare this definition with what Hobbes has to say about voluntary actions: “And because going, speaking, and the like voluntary motions depend always upon a precedent thought of whither, which way, and what, it is evident that the imagination is the first internal beginning of all voluntary motion. And although unstudied men do not conceive any motion at all to be there, where the thing moved is invisible, or the space it is moved in is, for the shortness of it, insensible; yet that doth not hinder but that such motions are. For let a space be never so little, that which is moved over a greater space, whereof that little one is part, must first be moved over that. These small beginnings of motion within the body of man, before they appear in walking, speaking, striking, and other visible actions, are commonly called endeavour.”
Both Hobbes and Hume are determinists in the great debate about free will and necessity, although they give very different analyses of causal judgments in general, and hence in particular of the causal judgments we make about human action. One can summarize Hume’s position succinctly as being simply this: the degree of observed regularity that gives rise to our causal judgments about objects is matched by the degree of regularity we observe in the behavior of persons. Hence, we are led quite properly and naturally to impute a similar causal necessity to that behavior.
I think a little reflection will tell us that Hume is in fact correct about the degree of regularity and predictability in the behavior of human beings. Think, for example, of driving at sixty miles an hour along a busy highway with traffic flowing in both directions. At every moment, I am counting on those going my way and those coming toward me to exhibit strictly predictable behavior. Indeed, my life depends upon it. I am as confident that the other drivers will not start swerving this way and that, reversing direction, and aiming their cars at mine, as I am that if I am hit by a car coming toward me at sixty miles an hour major damage will be done to me and to my car. The first belief rests on a causal judgment about people; the second rests on a causal judgment about physical objects. Both judgments arise out of the observation of the constant conjunction of resembling instances, as Hume argues in Book I, Part III.
Hume has a rather charming and puckish way of making the point. “Shou’d a traveler,” he says, “returning from a far country, tell us, that he had seen a climate in the fiftieth degree of northern latitude [ed. The latitude of London is 51.50 degrees], where all the fruits ripen and come to perfection in the winter, and decay in the summer, after the same manner as in England they are produc’d and decay in the contrary seasons, he wou’d find few so credulous as to believe him. I am apt to think a traveler wou’d meet with as little credit, who shou’d inform us of people exactly of the same character with those in Plato’s Republic on the one hand, or those in Hobbes’s Leviathan on the other.”
Hume goes on for some time in this vein, invoking his Book I analysis of causal necessity. I think it is not difficult for those reading this to imagine the line of argument. It suffices to quote the concluding line of the last paragraph of the section.
“According to my definitions, necessity makes an essential part of causation; and consequently liberty, by removing necessity, removes also causes, and is the very same thing with chance. As chance is commonly thought to imply a contradiction, and is at least directly contrary to experience, there are always the same arguments against liberty or free-will. If any one alters the definitions, I cannot pretend to argue with him, ‘til I know the meaning he assigns to these terms.”
It is worth noting that Kant agrees completely with Hume. The central conclusion of the Second Analogy in the Analytic of Principles of the Transcendental Analytic of the Critique of Pure Reason is that to exist in the realm of phenomena or appearances is to have determinate time location, and that is identical with standing in necessary causal connection to what preceded and what follows. To open the way for freedom of the will, Kant is forced to invoke the distinction between things as they appear to us in space and time and things as they are in themselves, and even then, he concludes that we cannot have knowledge of freedom, but only must presuppose it insofar as we undertake to act. But that is a subject for another tutorial entirely.