 The above provides a very general outline of one of the prominent intellectual approaches to natural philosophy in the Arabic-speaking world of the medieval period. The second major tradition of natural philosophy, falsafa, had its origin in Aristotle’s physical writings and the Graeco-Arabic commentary tradition that arose up  around them.[4]  Since natural philosophy, at least as it occurred in the Greek scientific tradition, is the study of natures, and natures are causes of motion or change, understanding what motion is and the conditions necessary for motions within a broadly Aristotelian framework was the primary focus of natural philosophers working in the falsafa tradition. Aristotle himself had defined motion as “the entelekheia of potential insofar as it is such” (Physics, III 1). One of the exegetical issues with which earlier Greek commentaries struggled was how to understand the enigmatic term entelekheia in Aristotle’s definition, a term it would seem that Aristotle himself coined. Some argued that entelekheia must refer to a progression or process towards some end or perfection. Others argued that entelekheia must refer in some sense to the completed actuality of some partial end or perfection. The dispute in the ancient world, then, settled upon whether entelekheia is itself a process term or not. If entelekheia is a process term then it is clear how Aristotle’s definition of motion describes a process, but it does so by assuming a process term in the definition, whereas Aristotle’s definition of motion was intended to provide the most basic account of what a process is and so should not presuppose a process. If entelekheia is not a process term, then Aristotle’s definition avoids circularity, but it is no longer clear how it describes a process, since a completion or perfection is the end of a process, not a process itself. The above roughly presents a key philosophical debate surrounding Aristotle’s definition of motion as it reached Arabic-speaking  philosophers.[5]