Mulla Sadra’s Theory of Substantial Motion

Abstract

Motion as traditionally defined is the gradual emergence of something from a state of potentiality to a state of actuality. A more simple definition is to say that motion is "gradual change." Before Mulla Sadra philosophers used to think that only some accidents are subject of motion, but motion cannot occur in substance; change in substance always takes the form of sudden generation and corruption. However, according to Mulla Sadra's theory of substantive motion, all corporeal beings whether substance or accident are in motion. Motion is not an accident that occurs in things; rather it is the mode of existence of material world. Motion and matter are not separable. Contrary to traditional philosophers who think that motion requires a subject in which it occurs, Mulla Sadra thinks that what is necessary for motion is continuous existence, not a stable subject. In his view, time is neither an illusion or mere imagination, nor an independent existent which exists on its own; rather it is the measure of motion and the fourth non-stable dimension of a corporeal being. A corporeal being has two extensions: spatial and temporal. The spatial extension is stable whose parts exist together in the state of existence, and the temporal extension is non-stable whose parts are passing and progressive and cannot exist simultaneously.