In his The Elements of Philosophy, William Wallace makes the following statement about motion: "“Motion (10:24c) can be taken in a wide and in a strict sense: in the wide sense it stands for any change (mutatio) from one state to another; in the strict sense, for continuous and successive change, usually spoken of as movement (motus). The latter is found in several different categories of being, and thus the elements of its definition must transcend the categories; the only available prior concepts for defining motion are those basic to being itself, viz. potency and act [§33.2]. Motion is situated midway between potentiality and full actuality. When a body is only in potency it is not yet in motion; when it has been fully actualized, the motion has ceased. Therefore, motion consists of incomplete act. But since incomplete act can be the termination of a motion or the starting point of a new motion, it is necessary to indicate motion as the act of being in potency precisely as still in potency to more of the same act. This line of reasoning led Aristotle to define motion as “the actualization of what exists in potency insofar as it is in potency.” This is usually spoken of as the formal definition of motion; the material definition is that motion is properly “the act of mobile being precisely as mobile.” By manifesting the connection between these two definitions one obtains the first demonstration in natural philosophy, which concludes that motion is the pervasive property of all mobile being and so properly exists in the thing moved, not in the mover as such [§20.2-3].” (PART 1. // CHAPTER 3 NATURAL PHILOSOPHY // [Section] §18. MOTION // [paragraph] 1 // [pages] 49 and 50)
My question for your consideration and response is the final line of the statement, which is "...motion is the pervasive property of all mobile being and so properly exists in the thing moved, not in the mover as such..." This statement, theologically and philosophically, fits nicely with the idea of a creator/nurturer/maintainer God who is not changed in his/her/its act of causing change/motion in other things. I get that. But in the realm of science, and especially in physics, what are examples of motion caused by something which is, itself, not moved or changed in the act of its causing other things to move/change?
Edited by Otto Piechowski, 15 January 2020 - 02:43 PM.