I agree that this is one possible explanation for the uncaused cause of all natural order. I agree that this satisfies our natural desire for religious understanding by appealing to our evolved instinct for projecting the human mind onto the world. But affirming this possibility as true is an act of religious faith, not of rational demonstration. This religious belief in an intelligently designed cosmos can be neither proven nor refuted by natural reason.
It is possible, therefore, for the theistic believer to be a theistic evolutionist, believing that the Intelligent Designer has used the natural evolutionary process to carry out His plan. C. S. Lewis, Alvin Plantinga, and many other theists have taken this position. But, again, this is an act of faith rather than reason.
Affirming the existence of a divine Mind as the intelligent designer of cosmic order cannot be proven by reason, because this is only one possibility among many that we can draw from our natural experience of order. Since there are many different principles of order that we might use to explain the cosmic order of nature, and since there is no demonstrative proof that one principle is better than all the others, we are left in a state of skeptical doubt.
As I have indicated in some recent posts, the supposed proof for the existence of a divine Mind depends on an anthropomorphic analogy of mental agency, which assumes that the natural order of the cosmos is an artifact that points to the mental agency of a divine artisan. Leo Strauss rejected this analogy in suggesting other possibilities: "One realizes the possibility that the first things originate all other things in a manner fundamentally different from all origination by way of forethought. The assertion that all visible things have been produced by thinking beings or that there are any superhuman thinking beings requires henceforth a demonstration, a demonstration that starts from what all can see now" (NRH, 89).
In this passage, Strauss doesn't explain what this alternative possibility is. But in his 1948 lecture on "Reason and Revelation," he did identify Darwin's evolutionary science as an alternative to divine creationism, and thus he put Darwinism on the side of reason against revelation.
In Cicero's De Natura Deorum, Cotta suggests various alternatives to Platonic and Stoic intelligent-design cosmology. In Hume's Dialogues Concerning Natural Religion, Philo lays out more clearly what these alternative possibilities might be, and he suggests the possibility of evolution by natural selection.
In the Dialogues (part 7), Philo argues that any attempt to explain the order of the universe depends on reasoning by analogy, where we look for some likeness between the order of the universe and the order of those things that we know by experience. Thus we must project the order of some small part of nature onto the whole of the natural universe.
Philo suggests that there are at least four such principles--reason, vegetation, instinct, and generation. The natural theology of intelligent design rests on the principle of reason as the source of order. From our experience with human mental agency in designing things and carrying out those designs, we might infer that the whole universe is the design of a mental agent. But we might just as easily employ the principles of vegetation, instinct, or generation. Plants grow from seeds and develop into intricately complex organisms. Animals engage in complex behaviors that manifest instinct. Animals generate offspring that grow into fully formed adults. In each case, we see principles of natural order that don't require reason. In fact, reason itself seems to be produced by animal generation, so that generation is prior to reason.
To say that all this order in animals and vegetables proceeds ultimately from design is begging the question; nor can that great point be ascertained other wise than by proving a priori, both that order is, from its nature, inseparably attached to thought, and that it can never, of itself, or from original unknown principles, belong to matter.
It all depends on judging likenesses:
The world, say I, resembles an animal, therefore it is an animal, therefore it arose from generation. The steps, I confess, are wide; yet there is some small appearance of analogy in each step. The world, says Cleanthes, resembles a machine, therefore it is a machine, therefore it arose from design. The steps are here equally wide, and the analogy less striking.
Or maybe the world was spun out by a cosmic spider:
The Brahmins assert that the world arose from an infinite spider, who spun this whole complicated mass from his bowels, and annihilates afterwards the whole or any part of it, by absorbing it again, and resolving it into his own essence. Here is a species of cosmology, which appears to us ridiculous; because a spider is a little contemptible animal whose operations we are never likely to take for a model of the whole universe. But still here is a new species of analogy, even in our globe. And were there a planet wholly inhabited by spiders (which is very possible), this inference would there appear as natural and irrefragable as that which in our planet ascribes the origin of all things to design and intelligence, as explained by Cleanthes. Why an orderly system may not be spun from the belly as well as from the brain, it will be difficult for him to give a satisfactory reason.
Later (in part 8), Philo comes close to formulating Darwin's theory of evolution:
It is in vain, therefore, to insist upon the uses of the parts in animals or vegetables and their curious adjustment to each other. I would fain know how an animal could subsist, unless its parts were so adjusted? Do we not find, that it immediately perishes whenever this adjustment ceases, and that its matter corrupting tries some new form. It happens, indeed, that the parts of the world are so well adjusted, that some regular form immediately lays claim to this corrupted matter: and if it were not so, could the world subsist? Must it not dissolve as well as the animal, and pass through new positions and situations; till in a great, but finite succession, it falls at last into the present or some other order?
It seems that what Darwin later developed in the theory of evolution specified what Hume considered a theoretical possibility.
And yet both Hume and Darwin (and Hume's character Philo) indicated that there was some plausibility to the design argument as based on the analogy to the human mind. In the Treatise on Human Nature, Hume declared: "The order of the universe proves an omnipotent mind." In the Natural History of Religion and the Dialogues, Hume acknowledges the power of the argument from design in supporting "true religion" or "philosophical theism," even as he exposes the weaknesses in such reasoning by anthropomorphic analogy.
Similarly, in his Autobiography, Darwin said that he often felt compelled "to look to a First Cause having an intelligent mind in some degree analogous to that of man; and I deserve to be called a Theist." But one page later, he concludes: "The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an Agnostic." Then, on the next page, he says that by the end of his life, he was governed by "scepticism or rationalism."
Does the powerful appeal of the argument from intelligent design show the power of our evolved natural instinct for religious understanding, which shows the working of what Justin Barrett and Jesse Bering identify as our "hyperactive agency detection device"?
In any case, Hume, Darwin, and Strauss show us that we can challenge that religious instinct by showing that the argument from intelligent design rests on an indemonstrable analogy. The natural desire for religious understanding is checked by the natural desire for intellectual understanding. We must choose between revelation and reason.
Some related posts can be found here here, here, here, and here.