Part II opens with a series of seemingly pious utterances by the various participants, with Philo, the sceptic, agreeing with Demea, the fanatic, that no one can possibly doubt the existence of God. Indeed, it is Philo who gives a first summary of the Cosmological Argument: "Nothing exists without a cause; and the original cause of the universe (whatever it be) we call God, and piously ascribe to him every species of perfection. Whoever scruples this fundamental truth deserves every punishment which can be inflicted on philosophers, to wit, the greatest ridicule, contempt, and disapprobation." This is actually a complicatedly ironic thrust, directed, though it does not seem to be, at the religious true believer, Demea.
In the Middle Ages, there was a lively debate, stretching over many centuries, about the meaning of such terms as "powerful," "wise," and "good" when used to describe God. A number of religious philosophers in the Arabic, Jewish, and Christian traditions insisted that God is so fundamentally different from the created world and its inhabitants that these terms cannot possibly mean the same thing when applied to God and Man. "Infinite," they said, merely has the negative meaning of "not finite," and conveys nothing positive about God's nature. The same is therefore true of "omniscient," "omnipotent," and "infinitely benevolent." This view stands in opposition to the older Stoic doctrine that man's reason is a spark of the Divine Reason, and therefore of the same nature, though of course finite rather than infinite.
It was not lost on contemporary commentators that the exaggerated piety of those who deny any commonality between the attributes of God and Man is indistinguishable from the impious atheism of those who deny the existence of God. Hume, I am certain, is echoing this debate, and setting up both Demea and Cleanthes for Philo's later sceptical attacks. By way of demonstrating the utter incomparability of God and Man, to which Demea has just given pious expression, Philo continues: "Our ideas reach no further than our experience. We have no experience of divine attributes and operations. I need not conclude my syllogism, you can draw the inference yourself." But this is exactly the argument, drawn directly from Book I of the Treatise, that Philo will use later to refute the Cosmological Argument.
Cleanthes follows this brief sketch of what will be a devastating refutation of all God-talk by shifting to the Argument from Design. "Look round the world," he says, "contemplate the whole and every part of it: you will find it to be one great machine, subdivided into an infinite number of lesser machines, which again admit of subdivision to a degree beyond what human senses and faculties can trace and explain." You can supply the rest of the argument, which even today is a commonplace of religious literature. As a machine bespeaks a designer, so the world evidences a purposeful Creator. "By this argument a posteriori, and by this argument alone," Cleanthes concludes, "do we prove at once the existence of a Deity, and his similarity to human mind and intelligence."
Immediately, Philo gives a counterargument drawn straight from the pages of the Treatise, an argument, I venture to say, that is absolutely dispositive. [I shan't quote his response -- as you will see, I am having difficulty keeping myself from simply quoting long passages of the text, since Hume writes so much better than I do.] The problem with this argument, Philo notes, is that we have only one instance -- one world to examine. In the case of our ordinary causal judgments, we have countless instances of the conjunction of cause with effect. We have seen many houses designed by architects and built by workmen; we have countless times observed the conjunction of fire with heat. But having only one world to examine, and lacking any direct observation of its creator, we are left with appeals to weak and questionable analogies. Much later in the Dialogues, Hume will have a good deal of fun with alternative speculative hypotheses of the origin of the observable world.
As the Emperor in Amadeus is wont to say, "Well, there it is." We have scarcely got through Part II of twelve parts, and both the Cosmological Argument and the Argument from Design are destroyed. What is Hume to do to keep his conversation afloat? His answer, to which he returns many times in the course of the Dialogues, is simply not to allow his characters to recognize that they have been defeated. I am reminded of the famous duel scene in Monty Python and the Holy Grail, in which a knight is progressively deprived of his arms, his legs, and even his torso, but still maintains that he is in the fight, threatening, when he has been reduced to nothing but a helmet-encased head, to bite his opponent's ankle.
A good example of this trope is to be found in the next Part, a relatively short passage entirely devoted to the Argument from Design. The locus classicus for this particular proof, by the way, is William Paley's extremely popular Natural Theology, or Evidences of the Existence and Attributes of the Deity collected from the Appearances of Nature, which was actually published in 1802, some twenty-three years after the appearance of Hume's Dialogues. Cleanthes launches into an impassioned statement of the Argument, even invoking that hoariest of examples, the human eye. "Consider," he says, "anatomize the eye, survey its structure and contrivance, and tell me, from your own feeling, if the idea of a contriver does not immediately flow in upon you with a force like that of sensation."
Now, after what Philo said in the previous Part, you would think, if Cleanthes were paying attention, he would recognize that this line of argument is a loser. And if this does not occur to Cleanthes, certainly it will to an alert reader. But it is way too early for anyone to concede defeat, so Hume has Hermippus step in [you will recall that he is telling Pamphilus about the conversation], and offer the following astonishing observation: "Here I could observe that Philo was a little embarrassed and confounded; but, while he hesitated in delivering an answer, luckily for him, Demea broke in upon the discourse and saved his countenance." Philo embarrassed and confounded? Thus far, he has had all the best lines!
If I may be allowed a second cultural reference, this one a trifle more respectable, Hume reminds me of Lenny in John Steinbeck's great novella, Of Mice and Men. Lenny, you will recall, is a great hulk of a man, enormously strong but rather simple-minded, and of a sweet, childlike demeanor. At one point, he is stroking a pet rabbit, and, not realizing his own strength, accidentally breaks its neck. I like to think of David Hume as a sweet, gentle man so smart that, without quite meaning to, he breaks the backs of age-old arguments when he was merely stroking them a bit.
Demea brings Part III to a close by reiterating the position of the utter unlikeness of the Divine and the Human. He concludes the Part by saying that "the infirmities of our nature do not permit us to reach any ideas which in the least correspond to the ineffable sublimity of the Divine attributes." Although this certainly sounds pious enough, it would, if taken seriously, consign all of Natural Religion to the ash heap. [If I may, like Tristram Shandy, digress once more, this is rather like an extraordinary outburst from Michele Bachmann in last night's debate among the Republican presidential hopefuls. Kept aloft by the divine afflatus of her own vacuous mind, Bachmann at one point delivered herself of the opinion that Americans should be able to keep every single dollar they earn, not quite realizing that this would result in the complete elimination of the office for which she was putting herself forward as a candidate.]