Chunghyoung Lee (Cal State, Fresno)

Talk Title:

"Infinity, Newton’s laws of motion, and a new argument for Preestablished Harmony"

Abstract

It is shown that the following common understandings of Newton’s laws of motion do not hold when they are applied to systems of infinitely many components. First, Newton’s third law, or the law of action and reaction, is universally believed to imply that the total sum of internal forces in a system is always zero. Several examples are presented to show that this belief fails to hold for infinite systems. Second, two of these examples are of an infinitely divisible continuous body with finite mass and volume such that the sum of all the internal forces in the body is not zero and the body accelerates due to this non-null net internal force. So the two examples also demonstrate the breakdown of the common understanding that according to Newton’s laws a body under no external force does not accelerate.

The implications of these examples on the debates on causality in the early modern period are discussed, and a new argument for Leibniz’s doctrine of Pre-established Harmony is presented.