SOURCE: "The Origin and Nature of Newton's Laws of Motion," in Beyond the Edge of Certainty: Essays in Contemporary Science and Philosophy, edited by Robert G. Colodny, Prentice Hall, 1965, pp. 29-68.

In the following essay, Ellis studies the historical origins of Newton's laws of motion and argues that contrary to popular belief the laws are more derivative of the physics of Descartes than the theories of Galileo. Ellis further emphasizes the conceptual nature of the laws, maintaining that they are not derived from or supported by observation or experimentation.

Are the laws of acceleration and of the composition of forces only arbitrary conventions? Conventions, yes; arbitrary, no—they would be so if we lost sight of the experiments which led the founders of the science to adopt them, and which, imperfect as they were, were sufficient to justify their adoption. It is well from time to time to...