Natural Right and History, suggests that a study of teleology in nature is important because the idea of natural right depends on it. Here’s an excerpt:
Natural right in its classic form is connected with a teleological view of the universe. All natural beings have a natural end, a natural destiny, which determines what kind of operation is good for them. In the case of man, reason is required for discerning these operations: reason determines what is by nature right with ultimate regard to man’s natural end. The teleological view of the universe, of which the teleological view of man forms a part, would seem to have been destroyed by modem natural science. From the point of view of Aristotle— and who could dare to claim to be a better judge in this matter than Aristotle?— the issue between the mechanical and the teleological conception of the universe is decided by the manner in which the problem of the heavens, the heavenly bodies, and their motion is solved. Now in this respect, which from Aristotle’s own point of view was the decisive one, the issue seems to have been decided in favor of the nonteleological conception of the universe. Two opposite conclusions could be drawn from this momentous decision. According to one, the nonteleological conception of the universe must be followed up by a nonteleological conception of human life. But this “naturalistic” solution is exposed to grave difficulties: it seems to be impossible to give an adequate account of human ends by conceiving of them merely as posited by desires or impulses. Therefore, the alternative solution has prevailed. This means that people were forced to accept a fundamental, typically modem, dualism of a nonteleological natural science and a teleological science of man. This is the position which the modern followers of Thomas Aquinas, among others, arc forced to take, a position which presupposes a break with the comprehensive view of Aristotle as well as that of Thomas Aquinas himself. The fundamental dilemma, in whose grip we are, is caused by the victory of modern natural science. An adequate solution to the problem of natural right cannot be found before this basic problem has been solved.This means that, according to Strauss, there are two options—first, we take a nonteleological view of both natural science and the science of man, and the second is that we become dualists, which means a teleological view of the science of man, and a nonteleological view other natural sciences.