Now alone with Cleanthes, Philo decides to reveal what he really thinks about the whole discussion. In a surprising move, he admits to his adversary that he actually believes in the design argument. It is impossible to ignore, he concurs, the fact that everything in nature serves its purpose, that nothing is in vain, and everything is done in the simplest, best manner. These tenets guide all of our scientific reasoning, and they undeniably point to the conclusion that there is some author of this order. No one, he tells Cleanthes, can really deny this. Even atheists have to admit it (and so there is no such thing as a true atheist). The only plausible source of disagreement lies in a dispute over the extent to which God's mind is like the human mind. The theist says that God's mind is like the human mind but not too like the human mind. The atheist, on the other hand, while forced to admit that there is likely some analogy between the human mind and the first cause of the universe, does not think that this analogy is very substantive.
Philo then begs forgiveness for any impious remarks he may have made in the course of their discussion. He explains that these remarks stem from his hatred of vulgar superstitions (among which he counts all organized religion). This launches Cleanthes and Philo into a discussion about the difference between true religion (a philosophical, rational belief in some higher power), which Philo believes in fully, and organized religion, which he hates passionately.
Philo claims that organized religion is utterly destructive. First, far from promoting morality (as Cleanthes claims it does) it is actually bad for morality, as it has been responsible for so much evil in the world: it has been the cause of innumerable civil wars, persecutions, oppressions, slavery. And this is not surprising either: by focusing the believer's attention on the salvation of his own soul, it encourages selfishness rather than selflessness. The religious man is likely to care only about himself and lack a highly developed capacity to care about others.
Not only is organized religion responsible for so much bad, but also Philo does not really see how it could be effective in promoting good. Organized religion tries to influence morality with promises of reward and punishment. But men are not motivated by distant, vague, uncertain promises. They are motivated by their natural inclinations. What motivates man to be good, he is convinced, is the basic human moral sentiment of benevolence, which inclines us towards empathy and a desire for justice in the world. This natural virtue, as he calls it, is more effective than organized religion in causing us to act morally.
Not only is organized religion morally dangerous, it also causes grief, gloom, and terror in its adherents. Organized religion arises from man's terror of uncertainty but instead of making him feel joy and consolation in the face of this terror, for the most part it only makes man more terrified and more gloomy by promising that he hangs in the balance between heaven and hell.
Philo's main complaint against organized religion is that in trying to say what God is like and what God wants, organized religion oversteps its bounds. The only warranted conclusion of natural theology, he says, is this: that the cause or causes of order in the universe probably bear some remote analogy to human intelligence. Anything beyond that cannot be revealed by reason, and must remain utterly mysterious. Philo ends with a paradigmatic fideist declaration. Philosophical skepticism, he says, is the most important and fundamental step toward true Christianity, because it is only when we realize the limited capacity of reason that we turn toward revelation. And it is only revelation that shows us the true way to worship God. Empirical theism, on the other hand, can lead straight to atheism because it looks to reason to account for everything and God cannot be found in this way.
In the last line of the book, Pamphilus resumes his commentary (which had lapsed as the discussion became more interesting) and declares that, of all the three ideas presented in the discussion, those of Cleanthes come closest to the truth.
What are we to make of this confusing last chapter? Philo switches his position and starts arguing for the design argument, he ends by affirming a fideist position, and finally Cleanthes is declared the victor? Of all the chapters in the Dialogues this one needs to be deciphered with the most care.
The first question to be addressed is what to make of Philo's sudden capitulation. Is he actually giving in and admitting that the design argument is fine, after showing how very not fine it is? Probably not, for if we read Philo's statement about design carefully, we will see that it is not at all inconsistent with the position he has been maintaining throughout. All he says is that there is evidence in the universe of some cause resembling human intelligence. There is nothing necessarily religious in this very weak analogy statement. All that Philo is really admitting is what we all knew all along: that our universe is not chaotic, but intricately run; that it seems to operate based on certain principles, such as simplicity; and that there must be some cause or other for these facts.
The more difficult question involves what to make of his fideist claims. Philo may well be a fideist (though it seems unlikely somehow, given his biting skepticism about matters beyond experience and his hatred of established religion) but could Hume have been? He was notorious in his day as an atheist, a reputation it would seem he could not have earned with a fideist streak in him. In addition, in his own writings (especially in the Natural History of Religion) he seems to indicate very clearly that he does not believe in God. Whether he really was an atheist, or whether he was rather an agnostic, is up for debate; but that he could actually have been a religious believer, harboring a blind faith founded on revelation is particularly unlikely.
One might try to make the case that Hume considered religious belief to be akin to our belief in the reality of causation: that is, unsupported by reason, but impossible to escape nonetheless. In the case of causation, Hume claims that we obtain the belief through a psychological process; in the case of religion, perhaps he might say that we obtain the belief through some sort of transcendent process. Several commentators have tried to make a case for this reading. But the case is never very strong. Hume engages in the psychological explanation of our belief in causation because he must explain the fact that we all do have this belief; since there is no rational basis for the belief, it must come from somewhere else. But not everyone believes in God, and so Hume has no reason to find a replacement for rational justification. In addition, he has a very plausible theory as to why some people believe, and this explanation has nothing to do with the fact that God really exists: people believe in religion, he tells us, because they are terrified of the unknown.
Assuming, then, that Hume was not a fideist, why does he have Philo end on this strongly fideist note? He probably does so because of his fear of religious retaliation. If his book had been perceived as a pro-atheist tract, it would probably not even have been published. By presenting his book as a fideist treatise, Hume is able to take on the empirical theist without as much risk. He would not mind embracing the fideist position, because he would agree with its claim that there is no rational basis on which to base a belief in God. It is the empirical theists that he is worried about, because empirical theists are drawing their religious conclusions based on the same sort of mental operations that he praises (that is, coming to belief based on evidence). The empirical theist believes himself to be following Hume's method of achieving truth; the fideist reaches his conclusions in a wholly unrelated manner.
Hume's fear of the religious powers that be might also account for the fact that Cleanthes is declared victor at the end of the book. It is also possible that this turn is a mere literary device: just as Pamphilus began the narrative, he must also end it, and who better to be declared victor than his teacher? Most likely, though, this device serves a more philosophical purpose: it is meant to counteract any misunderstanding that might arise (among sympathizers) from his pragmatic embrace of fideism. By declaring empirical theism closest to the truth, he is signaling that empirical theism is closer to the truth than fideism is. Since he has already demonstrated in the rest of the book that skepticism is closer to the truth than empirical theism, what he is really telling us with this line is that, despite what Philo was forced to say for safety's sake, skepticism is closest to the truth. Declaring Cleanthes as victor, then, is a safe and roundabout way of actually declaring skepticism as victor.