The Mechanics and Thermodynamics of Continua

The current entrenched, facile conception of force in terms of “pushes” and “pulls” has fostered a view of force as a “real quantity” rather than a mathematical concept. In the words of Pierce (1934, p. 262): [Force is] “the great conception which, developed in the early part of the seventeenth century from the rude idea of a cause, and constantly improved upon since, has shown us how to explain all the changes of motion which bodies experience, and how to think about physical phenomena; which has given birth to modern science; and which … has played a principal part in directing the course of modern thought … It is, therefore, worth some pains to comprehend it.”

Those who believe the notion of force is obvious should read the scientific literature of the period following Newton. Truesdell (1966) notes that “D'Alembert spoke of Newtonian forces as ‘obscure and metaphysical beings, capable of nothing but spreading darkness over a science clear by itself,’” while Jammer (1957, pp. 209, 215) paraphrases a remark of Maupertis, “we speak of forces only to conceal our ignorance,” and one of Carnot, “an obscure metaphysical notion, that of force.”