This study examines the defensive stance of Abu Nasr al-Fārābī in his treatise Fī al-Radd alā Yaḥyā al-Naḥwī (Response to Yaḥyā al-Naḥwī) against the criticisms raised by Yaḥyā al-Naḥwī (John Philoponus) concerning Aristotle's views. The article's primary focus rests on al-Fārābī's central hermeneutical claim that Aristotle's aim in "De Caelo" ("On the Heavens") was not to present a metaphysical proof for the "eternity of the world," but rather to offer a physical and descriptive explanation of the "cosmic structure" and the nature of celestial bodies. By employing an analytical-critical method, the present article demonstrates that al-Fārābī, by decisively distinguishing between these two levels of discourse - the physical and the metaphysical - pursues two main objectives: first, to defend the internal coherence and explanatory power of the Aristotelian physical system against Philoponus's objections; and second, to open a philosophical path for reconciling the theory of the "ethereal body" (which constitutes the celestial spheres) with the fundamental principle of the "temporal origination of the world" in Islamic theology. By analyzing the inner dialectic of al-Fārābī's defense and explaining its theological-philosophical implications, this research consciously distinguishes itself from Mohsin Mahdi's descriptive-historical study of the same treatise, emphasizing instead the philosophical and integrative aspects of al-Fārābī's strategy.