The Grounding of the Philosophic or Scientific Life
That doubt is recaptured and preserved in Strauss’s exchange with Kojeve. The claim that the ancients were right entails a “presupposition” about “nature,” he admits. Strauss does not make this admission in passing. On the contrary, in the conspicuous concluding paragraph of the “Restatement”—his rejoinder to Kojeve—he goes out of his way to address these “absolute presuppositions” of classical philosophy, using the language of historical thinkers like Kojeve and Heidegger.
For the question arises immediately whether the idea of philosophy is not itself in need of legitimation. Philosophy in the strict and classical sense is quest for the eternal order or for the eternal cause or causes of all things. It presupposes then that there is an eternal and unchangeable order within which History takes place and which is not in any way affected by History. It presupposes in other words that any “realm of freedom” is no more than a dependent province within “the realm of necessity.” It presupposes, in the words of Kojeve, that “Being is essentially immutable in itself and eternally identical with itself.” This presupposition is not self-evident. (OT 212)
As he does elsewhere (often by using a quietly disjunctive “or”) Strauss here presents a series of possibilities, in this case, a list of possible “presuppositions” of philosophy (the last of which is explicitly stated in Kojeve’s own words, not in Strauss’s). The statements are not equivalents, and Strauss leaves it to the reader to discern which is most seriously intended. But he indicates elsewhere that one version of these presuppositions concerning the possibility of science is true, and that the alternatives to this presupposition are either the Biblical doctrine of creation or Heidegger’s doctrine of Dasein, both of which are fatal to philosophy. The passage I have in mind, which occurs in Natural Right and History, is arrived at after Strauss has given an account of the emergence of philosophy or science through the discovery of “nature”:
The philosophic quest for first things presupposes not merely that there are first things but that the first things are always and that things which are always or are imperishable are more truly beings than the things which are not always. These presuppositions follow from the fundamental premise that no being emerges without a cause or that it is impossible that “at first Chaos came to be,” i.e., that the first things jumped into being out of nothing and through nothing. In other words, the manifest changes would be impossible if there did not exist something permanent or eternal, or the manifest contingent beings require the existence of something necessary and therefore eternal. . . . One may express the same fundamental premise also by saying that “omnipotence” means power limited by knowledge of “natures,” that is to say, of unchangeable and knowable necessity; all freedom and indeterminacy presuppose a more fundamental necessity. (NRH 89-90)
Strauss nowhere implies that the “necessity” in question is Being (ousia), nor does he suggest that the first things to which he refers are knowable. He does argue clearly—if implicitly—against Heidegger’s claim that the classical premise that “to be” means “to be always” follows from the understanding that “to be” means “to be present.”  It instead follows, Strauss points out, from the premise— required by the original meaning, genesis, and motivation of science, to know the nature that is there independent of any will human or divine—that no being emerges without a cause (in Latin, ex nihilo nihil fit), a proposition Heidegger for his part tries to avoid addressing. Still elsewhere Strauss presents the Heideggerian (and Biblical) alternative to this fundamental premise of science as ex nihilo et a nihilo omnia fiunt4 Heidegger’s account of the motivation of classical philosophy was, then, quite mistaken. Yet it remains true that one cannot justify science or philosophy if this “presupposition” is merely the result of a choice or decision, rather than demonstrated.
Passages in chapter 4 of Natural Right and History, a chapter to which Strauss later explicitly directed Kojeve, help us to see that because there was indeed thought to be a problem with knowing those first causes or necessities, science was thought to be endangered. Strauss there presents the new Socratic approach to the study of nature as a whole—the attempt to learn “what each of the beings is”—as entailing a turn away from the pre-Socratic attempt to discover the first things or underlying causes of all the beings, a turn made when that earlier attempt came to seem to Socrates to be impossible. The new Socratic approach had therefore to be open, in a way that pre-Socratic philosophy had not been, to the possibility that a divine source was responsible for those beings. And so Socrates had to commence a new approach to settling the decisive question—which had to be settled—of whether those underlying sources were indeed causes or were instead divine creations. He had to settle the matter of whether what appear to be necessities are not actual necessities but the work of a god or gods who make all beings come into being out of nothing. It is to settling this matter that the dialogues of Plato and Xenophon are directed.
Strauss’s extraordinary implication is that this intention of classical political philosophy was overlooked by the moderns, who therefore turned to a different attempt to resolve the problem, an attempt that entailed both what we have (following Strauss) called a “retreat into consciousness” or to an “artificial island,” and an attempt to transform the given world, or to erect the City of Man “on the ruins of the City of God” (NRH 175). In On Tyranny, Strauss begins the publication of his recovery of the classical grounding of science or philosophy, examining a dialogue resulting from a Socratic’s turn to the human things.
-  On the term “absolute presuppositions,” see Strauss, “Existentialism” ,310.
-  “[According to Heidegger] Greek philosophy was guided by an idea of Seinaccording to which Sein means to be ‘at hand,’ to be present, and therefore Seinin the highest sense to be always present, to be always.” Leo Strauss, “The Problem of Socrates,” Interpretation: A Journal of Political Philosophy 22 (no. 3, Spring1995): 328. See also NRH 30-31.
-  Strauss, “The Problem of Socrates,” 327-329.