In this section, Philo begins a new line of attack against the argument by design. Like the previous contention, this one draws on the fact that the evidence we have available to us is simply too scant to support any substantive conclusions regarding God's nature. Here, however, instead of showing that the evidence of design in our universe cannot lead to anything but the vaguest notion of a designer or multiple designers, Philo shows that the evidence provided by our universe supports many analogies, not just the analogy to design. Given that the evidence supports all of these analogies equally well, he argues, we have no basis on which to accept one over the other. Comparing the universe to a machine is just one possible way of conceiving of the world. For instance, the universe is also kind of like an animal body or a plant, in that both display a high degree of order. We can think of many familiar objects to which the universe bears some resemblance; obviously this does not mean that universe actually is an instance of each of these objects.
Though Philo claims that he can think of many such analogies, he chooses to focus on in this chapter an analogy between the universe and an animal body. According to this picture, the material world is like a body, and God is to the world what a soul or mind or is to an animal body. Philo chooses this analogy in large part because it was a very popular worldview in ancient civilizations. The universe is like an animal in that it is ordered; it is a closed system; the various parts of the universe work together in the way that the parts of a body work together; and every part operates both for its own preservation and for the preservation of the whole. In addition, there is also a further reason to believe this analogy: if we think that God is incorporeal mind, then He should really have some sort of body. After all, in all of our experience every mind has been somehow attached to a body. Experience, then, actually supports this analogy better than the mechanistic analogy. And if Cleanthes wants to object that our experience is limited and that mind could easily exist without body, then he must give up his own argument as well: once he admits that our experience is too narrow to act as a foundation for inferences to larger truths, then he admits that his own argument is faulty, for he has assumed that our experience must provide a good analogy for the entire world in using the argument by design. His argument also tries to rest its inference on the narrow, limited realm of human experience. Cleanthes responds to Philo's points by trying to reveal defects in the alternative analogy Philo poses: the universe, he points out, has no sense organs like an animal does, no seat of thought, no origin of motion or action. In fact, Cleanthes points out, the universe is more like a vegetable body than like an animal body. So one could not really use this analogy to conclude what kind of soul the world has (i.e. what God is like): it would leave the conclusion indeterminate between an animal soul and a vegetable soul.
His other major gripe with the analogy is that it implies that the world is eternal. The world would have to be eternal on this view because God is eternal and if God is the soul and the universe is his body, then he could not have existed before the universe. But the world, Cleanthes declares, is demonstrably not eternal. In fact, it is obviously fairly young. If it were not young, he argues, then it would not have been so recently that a European discovered America, that grape vines were introduced into France, that cherry trees were introduced into Europe, and so on. If the world were eternal then surely all these things would have been done before.
Philo replies to this line of reasoning with the obvious rebuttal: to claim that the world is eternal, is not to claim that it was eternally like it is now. Perhaps it is true that if the there were always human beings living in environmental conditions roughly like those that exist at present, then all of these recent events would have transpired much earlier. But given that the world could have been vastly different for much of its existence (e.g. there might have been no human beings, the whole earth could have been covered with water, there might not even have been a planet earth) there is no reason to think that these events should have happened any earlier than they did.
Philo ends the section by suggesting a purely material explanation of an ordered world. If he had to choose one system of nature as more plausible than all others, he would choose a system that involves an eternal principle of order at work in the material world.
In rebutting Philo's contention that the world is analogous to an animal body, Cleanthes argues that the evidence does not support the new analogy. He makes two points in support of this thesis. The first point he makes is that the analogy between the universe and an animal does not fit because there are ways in which the universe is not analogous to an animal body. Animal bodies have sense organs while the universe does not; animal bodies have motive power while the universe does not; animal bodies have a seat of thought while the universe does not. The other point makes is that all the evidence Philo has given for claming that the universe is an animal body fits just as well (actually, better) an analogy to a vegetable body. Cleanthes thinks that because the evidence does not determine whether an animal or a vegetable body is analogous to the universe, we cannot use either to draw any conclusions about God's nature. One could reply to Cleanthes that we do not know whether the universe has organs of sensation, as we can only know that something is a sensory organ if it is analogous to one we possess. Perhaps the universe has different sensory organs than we do, or perhaps its organs exist on such a large scale (perhaps they are made up of entire solar systems) that we cannot tell that they exist. Further, the claim that an analogy cannot illuminate unless it fits perfectly is destructive to Cleanthes's case. There are numerous ways in which the universe is not analogous to a product of human design. For instance, a product of human design always has some one purpose for which it was obviously created while the universe has no such discernible purpose.