In his lecture in 1948 on "Reason and Revelation," Strauss indicated that the irreconcilable conflict between revelation and philosophy or science is manifest in the conflict between the Biblical story of Creation and Darwinian evolutionary science.
In "Progress or Return?" (1952)--reprinted in The Rebirth of Classical Political Rationalism--Strauss puts this conflict in the context of "the basic question of how to find one's bearings in the cosmos." He explains:
"The Greek answer fundamentally is this: we have to discover the first things on the basis of inquiry. We can note two implications of what inquiry means here. In the first place, inquiry implies seeing with one's own eyes as distinguished from hearsay; it means observing for oneself. Secondly, the notion of inquiry presupposes the realization of the fundamental difference between human production and the production of things which are not manmade, so that no conclusion from human production to the production of nonmanmade things is possible except if it is first established by demonstration that the visible universe has been made by thinking beings. This implication, I think, is decisive: it was on the basis of the principles of Greek philosophy that what later became known as demonstrations of the existence of God or gods came into being. This is absolutely necessary, and that is true not only in Aristotle, but in Plato as well, as you see, for example, from the tenth book of the Laws. An ascent from sense perception and reasoning on sense data, an ascent indeed guided, according to Plato and Aristotle, by certain notions, leads upwards; and everything depends on the solidity of the ascending process, on the demonstration. The quest for the beginning, for the first things, becomes now the philosophic or scientific analysis of the cosmos; the place of the divine law, in the traditional sense of the term, where it is a code traced to a personal God, is replaced by a natural order, which may even be called, as it was later to be called, a natural law--or at any rate, to use a wider term, a natural morality. So the divine law, in the real and strict sense of the term, is only the starting point, the absolutely essential starting point, for Greek philosophy, but it is abandoned in the process. And if it is accepted by Greek philosophy, it is accepted only politically, meaning for the education of the many, and not as something which stands independently" (255-56). (Also in K. H. Green's edited anthology, Jewish Philosophy and the Crisis of Modernity, pp. 113-14.)
As Strauss indicates here, the proofs for the existence of God by inferring invisible divine causes from visible natural effects were first developed by Plato and Aristotle--particularly, in Book 10 of the Laws, where Plato sketched the reasoning for intelligent design theory or natural theology, the same fundamental reasoning later developed in medieval natural theology and in the contemporary intelligent design theory of Bill Dembski and Michael Behe. Paul first introduced this into Christianity in his Letter to the Romans (1:20), when he declared (under the influence of Greek philosophy): "The invisible things of Him are clearly seen, being understood by the things that are made."
Strauss also indicates, however, the essential fallacy in such reasoning--"the fundamental difference between human production and the production of things which are not manmade, so that no conclusion from human production to the production of nonmanmade things is possible except if it is first established by demonstration that the visible universe has been made by thinking beings." Indeed, this anthropomorphic assumption that our experience of human mental agency can be projected onto the cosmos runs through Plato's reasoning in the Laws and the longing of Plato's Socrates for a cosmos ruled by Nous. Dembski shows this same anthropomorphic assumption when he says: "The point of the intelligent design program is to extend design from the realm of human artifacts to the natural sciences." This rhetorical strategy hides the fact that while detecting the design of human artifacts is a matter of common observation and logic, detecting the design of divine artifacts is not, because while the working of human intelligent design is known by natural experience, the working of divine intelligent design is not.
The rational ascent to divine law is the starting point for Greek philosophy, but a starting point that is abandoned in the move from divine law to natural order or natural law. This requires the fulfillment of Greek natural philosophy, which sought to explain the cosmic whole as a product of nature and chance, within which human art could arise through custom and reason(Laws, 888e-89e).
But Greek natural philosophy faced three seemingly insurmountable problems. The first problem was that despite the weaknesses in the intelligent design argument, there did not seem to be any plausible alternative for explaining the apparent design in the natural world. If the irreducible complexity in the universe is not a product of divine design, then how else can we explain it?
The second problem was that a purely naturalistic explanation of the cosmos could not easily explain human moral order without falling into a radical relativism or nihilism. If the cosmos is not the product of a God who is also a moral lawgiver, does this mean that there is no cosmic support for human morality, which is a purely artificial and therefore arbitrary product of human will?
The third problem is that it's unclear whether even the most successful natural philosophy can refute the claims of revelation. If natural philosophy must assume that miracles are impossible--that there are no breaks in the causal regularities of nature--doesn't this beg the question at issue? How does natural philosophy prove the impossibility of miracles, including the impossibility of miraculous revelation in which some human beings can have a direct experience of God? (Actually, this third problem did not emerge clearly until Greek philosophy confronted the scriptural religions of the Bible and the Koran in the Middle Ages.)
Darwinian science supports the fulfillment of natural philosophy by solving--at least in principle--the first two problems. But it leaves the third problem unresolved.
Darwinian science solves the first problem by showing how natural order can arise through an evolutionary process of spontaneous order emerging from random variation and selective retention, by which irreducibly complex orders can arise without intentional design.
Darwinian science solves the second problem by showing how moral order can arise through the natural evolution of a human moral sense shaped by social instincts, social learning, language, and deliberate judgment. The human good is not a cosmic good, but it is a natural good in so far as it conforms to human nature.
Darwinian science does not solve the third problem--the reason-revelation debate--because it cannot refute the possibility of miracles--the possibility of miracles in natural history that are not detectable by natural science or the possibility that natural evolution itself is a miracle as arising from laws of nature originally created by nature's God or the possibility that some human beings can directly experience a revelation of God's presence.
Darwinian science can explain the evolutionary psychology of religious belief as prompted by the anthropomorphic fallacy, because it can explain this as an extension of our evolved social disposition for "mind reading" and detecting agency. As cognitive scientists like Jesse Bering and Justin Barrett have shown, we can explain the natural desire for religious understanding as the work of a "hyperactive agency detection device," which was first suggested by Darwin in his evolutionary theory of religion in The Descent of Man.
And yet even this does not resolve the reason-revelation debate, because even if we accept this evolutionary explanation of religious belief, we are free to see religion as either an adaptive illusion (as Bering does) or as an adaptive truth (as Barrett does).
In any case, Darwin made it clear--especially in his Autobiography--that in the choice between the life of reason and the life of revelation, he had deliberately chosen the life of reason: "As for myself, I believe that I have acted rightly in steadily following and devoting my life to science."
Related posts can be found here, here, here, here, here, here, here, and here.