Cleanthes, who in part represented English natural theologians in Hume’s day, argued not only that the complexity of the world proved that it was designed, but that the world was a happy place and this was evidence for god.
Hume had an easy time ridiculing this view. Philo, who represented Hume, as well as Demea agreed that “A perpetual war is kindled amongst all living creatures,” and that nature is arranged so as “to embitter the life of every living being.”
If the natural theologian’s god would have the world be happy, and yet the world is not happy, then we must seek a different god. Philo concluded, against Cleanthes, that god does not will the happiness of man nor animal.
Cleanthes’s design argument was powerful. Philo admitted the argument was a great challenge for him, but it was neutralized by the evil in the world. “I needed all my skeptical and metaphysical subtlety to elude your grasp,” admitted Philo, but “Here I triumph.”
For Philo, the world’s evil indicated a more distant and mystical god. He charged Cleanthes with anthropomorphizing god. Cleanthes, said Philo, made god out to be too much like His human creatures. For example, the natural theologians were fond of comparing the human body with machines such as clocks. No one doubts that a clock was designed, so why not the body as well? Hume, through his character Philo, used the problem of evil to negate this argument. Better to view god as distant and unknowable, and a creation that somehow arose on its own.
Hume had no problem with god being infinitely powerful and wise, but he must also be transcendent and incomprehensible:
But as all perfection is entirely relative, we ought never to imagine that we comprehend the attributes of this divine being, or to suppose that his perfections have any analogy or likeness to the perfections of a human creature. Wisdom, thought, design, knowledge; these we justly ascribe to him; because these words are honorable among men, and we have no other language or other conceptions by which we can express our adoration of him. But let us beware, lest we think that our ideas anywise correspond to his perfections, or that his attributes have any resemblance to these qualities among men. He is infinitely superior to our limited view and comprehension; and is more the object of worship in the temple, than of disputation in the schools.
In other words, while we may have faith in god, we must not think we understand him well enough to infer his actions in the material world. He may be the god of our hearts, but not of our heads. As Darwin would later argue, while it is tempting to see god as the master engineer who crafted complex organs such as the eye, this would make god too much like man.
Darwin agreed that the perfection of the eye reminds us of the telescope which resulted from the highest of human intellect. Was it not right to conclude that the eye was also the product of a great intellect? This may seem the obvious answer but Darwin warned against it, for we should not “assume that the Creator works by intellectual powers like those of man.” Better to imagine the eye as the result of natural selection's perfecting powers rather than having god too much involved in the world.
This anthropomorphic warning and the problem of evil were by no means Hume’s only arguments for a purely naturalistic origins story. There was, for example, the problem of dysteleology:
And what surprise must we entertain, when we find him a stupid mechanic, who imitated others, and copied an art, which, through a long succession of ages, after multiplied trials, mistakes, corrections, deliberations, and controversies, had been gradually improving? Many worlds might have been botched and bungled, throughout an eternity, ere this system was struck out: Much labour lost: Many fruitless trials made: And a slow, but continued improvement carried on during infinite ages of world-making.
Here Hume converts metaphysical arguments against design into an anticipation of Darwinian evolution and even the multi-verse. The eighteenth century Linnean hierarchy was revealing a biological world of repeated designs. Was this not the sign of “a stupid mechanic, who imitated others, and copied an art”? As Niles Eldredge recently explained:
Could the single artisan, who has no one but himself from whom to steal designs, possibly be the explanation for why the Creator fashioned life in a hierarchical fashion—why, for example, reptiles, amphibians, mammals, and birds all share the same limb structure?
Hume also argued that the design argument raised a fatal infinite regress. Divine creation explains the world’s complexity and evidence of design as the result of the creator. The world is complex so it must have been created. But doesn’t this mean that the creator is also complex, and so must have been created? Using this logic we would then need to ascribe the intelligence of the creator to an even greater creator, and so on. Divine creation leads to an infinite regress of creators.
“How therefore shall we satisfy ourselves,” asked Hume, “concerning the cause of that being, whom you suppose the author of nature?” Is it not arbitrary to stop at the first Creator? “If we stop, and go no farther; why go so far? Why not stop at the material world? How can we satisfy ourselves without going on ad infinitum? And after all, what satisfaction is there in that infinite progression?”
Or as one recent evolutionary textbook put it:
Omnipotent beings are themselves well-designed, adaptively complex, entities. The thing we want to explain has been built into the explanation. Positing a god merely invites the question of how such a highly adaptive and well-designed thing could in its turn have come into existence.
These are but a few of the metaphysical arguments that called for an evolutionary narrative in the Enlightenment years. And they did not begin, nor end, with the Enlightenment. Hume marshaled several of the powerful and timeless arguments that laid the foundation for Darwin. From a scientific perspective it could not be more obvious that evolution is a stretch. The biological world just happened to arise all on its own? And this is said to be an undeniable fact, as much as is gravity? It is astonishing that grown men engage in such folly.
But from a philosophical and theological perspective, evolution is compelling. If the evolutionists are correct about even just one of their many metaphysical arguments, then evolution must be true. The uncertain details, as evolutionists like to say, deal with how it happened, but there must be no question that it happened. Religion drives science, and it matters.