The Dialogues can be compared to a classic musical trio, in which first one instrument and then another states a theme or offers a variation. This use of three equal speakers gives Hume a certain flexibility that is lacking from Plato’s Dialogues, where Socrates is always one of the interlocutors, and there can be no question who speaks for the author. The entire set of Dialogues, or Parts, is introduced by two characters, Pamphilus and Hermippus, who report on the conversation but take no part in it. Pamphilus does his best to shape our understanding of the debate, in a way that is fundamentally and deliberately misleading, by speaking, in the last paragraph of the Introduction, of “the accurate philosophical turn of Cleanthes,” the “careless skepticism of Philo,” and the “rigid inflexible orthodoxy of Demea.” Thus the reader is encouraged to view Cleanthes as the sensible medium betwixt the extreme skepticism of Philo and the equally extreme dogmatism of Demea.
This thematic characterization is continued as the First Part opens, with Cleanthes saying to Philo, “Whether your skepticism be as absolute and sincere as you pretend, we shall learn by and by, when the company breaks up; we shall see then whether you go out at the door or the window, and whether you really doubt if your body has gravity or can be injured by its fall, according to popular opinion derived from our fallacious senses and more fallacious experience.”
It is interesting to examine this jibe in the context of Hume’s arguments in the Treatise, which we have just finished examining. Hume, you will recall, first demonstrates that our belief in causal inference cannot be sustained by Reason, but almost immediately acknowledges that we are so constituted as to be led ineluctably, by our human nature, to associate together constantly conjoined resembling instances, and then to convey some measure of the vivacity of the impressions to the associated ideas, which is to say, to believe them. Thus, for all purposes beyond the sceptical critique of rational justifications of causal inference, Hume is prepared to accept and rely upon our beliefs in causal connections. Shortly after the sardonic jibe from Cleanthes that I have quoted, Hume has Philo say “To whatever length any one may push his speculative principles of skepticism, he must act, I own, and live, and converse, like other men, and for this conduct he is not obliged to give any other reason than the absolute necessity [ed. The psychological necessity, that is] he lies under of so doing.” Here Philo is echoing Cleanthes, not disagreeing with him, once again leaving us uncertain who is voicing Hume’s own views.
But now Philo continues in this apparently agreeable fashion to indicate the limits of such appeals to causation. “So long as we confine our speculations to trade, or morals, or politics, or criticism, we make appeals, every moment, to common sense and experience, which strengthen our philosophical conclusions and remove, at least in part, the suspicion which we so justly entertain with regard to every reasoning that is very subtile and refined.”
As the Dialogues proceed, we shall see Philo, and sometimes Cleanthes, demonstrating that every attempt to extend our causal inferences beyond the sphere of experience to the existence and nature of an infinite deity is precisely the sort of “subtile and refined” reasoning that cannot be justified. This is in fact the central sceptical move that Hume makes in response to each attempt to prove the existence or discern the nature of a Divine Being.
What I want you to see here is the skill with which Hume parcels out his arguments to Philo and Cleanthes so that he can conceal from view the fact that it is Philo’s unrelenting skepticism that expresses Hume’s true convictions.
There is really nothing more of important to say about Part I, which is purely introductory, but I cannot resist quoting one passage that seems to be directed not at eighteenth century fanatics but at their contemporary American counterparts. Cleanthes speaks of “brutish and ignorant skepticism … which gives the vulgar a general prejudice against what they do not easily understand, and makes them reject every principle which requires elaborate reasoning to prove and establish it.” Such people, Cleanthes goes on, “firmly believe in witches, though they will not believe nor attend to the most simple propositions of