Astronomical Images : Proof that no infinite body has finite power

Aristotle

Astronomical Images

<p style='text-align: justify;'>This work comprises Aristotle's <i>Physics</i> and Thomas Aquinas's commentary edited by the Augustinian, Timoteo Maffei of Verona (d. 1470). Aristotle discussed the nature of motion in the latter books of <i>Physics</i>, often referring to figures to elucidate his points. These figures were not always illustrated, and there was no traditional stock of figures like the wind diagrams or concentric circles associated with the Aristotelian analysis of motion. This edition makes an effort to supply such figures. In <i>Physics</i>, book 8 chapter 10, Aristotle seeks to show that the Prime Mover is without parts or magnitude. This entails showing that the power of an unlimited body cannot be limited. The top part of the woodcut shows a time bar labelled as the time in which an infinite body with finite power moves D. A leg labelled AB represents the unlimited body pushing a mobile object D. Section BC, a finite power from AB, is shown as one hand holding D; the time it takes for BC to move D is given as EZ on the bar above it. The figure below shows the doubling of this finite force as two hands holding D. Twice the force of BC will produce the same effect in half of the time TZ shown above it as a bar. Continuing the additions will not exhaust AB, but at some point will reach the multiple of BC which will move D in less than any given period of time. The motive power of AB then has no limit, for it exceeds any limited power one might choose to start with. (Aristotle, <i>Physics</i> VIII.10.266b7-24, trans. Wicksteed and Cornford.)</p>