The Dialectic of Philoponus and Avicenna on the Eternity or Temporality of the World

In his two treatises, "Refutation of Proclus" and "Refutation of Aristotle," Philoponus presented innovative arguments based on the concept of the infinite - such as the impossibility of traversing an infinite series and the impossibility of augmenting the infinite - in order to refute the doctrine of the eternity of the world, motion, and time, and to demonstrate their temporal origination. These works were translated into Arabic during the translation movement and influenced Muslim thinkers; scholars such as al-Naẓẓam and al-Kindi accepted and developed these arguments. Avicenna, the prominent Islamic philosopher, in his works - particularly in "Al-Isharat wa al-Tanbihat" - without mentioning Philoponus by name, transmitted his arguments in three main axes (the impossibility of an actual infinite, the impossibility of traversing an infinite series, and the impossibility of augmenting the infinite) and then subjected them to systematic critique. With the loss of the Arabic translations of Philoponus's two refutations, the origin of these novel ideas concerning the world's temporality remained unknown, and the hidden historical dialectic between him and Avicenna escaped the attention of researchers. This research, employing a historical - analytical method and relying on available sources, seeks to break this silence. The aim is to precisely explain how Avicenna engaged with Philoponus's philosophical challenge and to analyze his response based on the key distinction between the "actual and potential infinite" and the theory of "essential origination" (al-ḥuduth al-dhati). The findings indicate that this confrontation was a constructive dialogue that compelled Avicenna to deepen and systematize the concepts of eternity, temporality, and causal relation in Islamic philosophy.