Machines, Mechanism, and the Development of Mechanics: Contemporary Understandings

The early modern period is a source of nearly inexhaustible studies for historians and philosophers of science, and it is reasonably safe to conclude that it will remain so for the foreseeable future. Yet there have been significant changes in historiographic tendencies over the last few decades, and it is useful to pause and reflect on where we are in our understanding of the scientific and mathematical developments from the late sixteenth through the early eighteenth centuries. The period was once commonly known as the "Scientific Revolution," (a coinage due to the great Alexandre Koyré), and much scholarship from the twentieth century stressed the abrupt and seemingly irreversible shift in scientific outlook between the publication of Copernicus's De Revolutionibus orbium coeliestium in 1543 and Newton's Philosopiae Naturalis Principia Mathematica in 1687. The focal point of this supposed revolution was the development of the modern science of mechanics, and the books under review are all concerned to one degree or another with outlining the history of mechanics.

One fundamental issue, at once terminological and conceptual, is salient in any discussion of the history of mechanics. This is the simple fact that the term 'mechanics' (or, more properly, the Latin mechanica or French méchanique) underwent a significant shift in meaning between the thirteenth and eighteenth centuries. The medieval science of mechanics, operating in the tradition derived from Aristotle, employed a fundamental principle that constant application of force is necessary in order to keep a body in motion. Aristotle and the Aristotelian tradition also distinguished between natural and violent motions—the former arising from a material body's substantial form (or internal principle of motion and rest) and directed toward a the body's "natural place," while the latter oppose the ordinary course of nature and are the result of an externally applied force. The study of simple machines in this tradition was seen as a way to understand how one might intervene in nature to produce motions that would ordinarily not arise. The Archimedean water screw, for example, produces an effect contrary to nature by making water move upward, and the Aristotelian tradition understood mechanics generally as the study of machines, namely devices that produce effects not found in nature.

By the time of Newton, the term 'mechanics' had come to mean something very different, namely a mathematical study of motion that includes such concepts as force, momentum, acceleration, and resistance. Newton's Principia is the terminus ad quem in Dijksterhuis's famous study he termed Mechanisering van het wereldbeeld or The Mechanization of the World Picture, and it is no great exaggeration to say that by the end of the seventeenth century the informed scientific consensus was that the world was a gigantic machine, governed by laws that dictate how material bodies move, collide, and otherwise interact. The consequence is that machines, far from being something opposed to the natural order as they were in the Aristotelian account of mechanics, had by 1700 become the model for how nature operates at both the celestial and terrestrial levels. The story of how this great transformation in European thought took place is a central part of the works under discussion here, although there are significant differences is scope and emphasis.

Michael J. Crowe's Mechanics: from Aristotle to Einstein is intended as a text for advanced undergraduates or first-year graduate students in a history of science course. The work is ambitious in its scope, seeking to delineate the transformation of mechanics from the ancient world to the early...