Perspectives in Biology and Medicine

SUBJECTIVE EXPERIENCES AND THE CONCEPT OF ENERGY STANLEY W. JACKSON* Introduction A study of the history of the concept of energy in science has led to the recurring impression that something critical is missing from the explanations proffered. Although writers on this subject tend to agree on certain themes, many ofthem also suggest factors which go unmentioned in most of the other accounts. In spite of the multiplicity ofpossible influences thus considered, attention is usually restricted to the "internal" history ofscience with its narrow range oftraditional types ofdetermining elements. Without wishing to detract from the significance ofthese considerations , I suggest that yet another factor, man's subjective experience of effort, energy, or vigor, has also played a critical role in the origins and development ofthe concept ofenergy. Historians1 frequently tell ofthe arguments between the Cartesians and theLeibnizians as to whether momentum (mass X velocity) or vis viva (mass X square ofvelocity) was the quantity conserved in any dynamic situation. Newton's quantity of motion (mass X velocity) is brought into some of these accounts of the continuing debate. Huygens is sometimes credited with a significant role in the establishment of the idea that it is vis viva that is conserved. There is usually some indication of how these various notions came to be recognized as separate factors, or types of "force," each with its own functions in the domain ofphysical science, and mention is often made ofYoung's suggestion in 1807 that the term "energy" be applied to Leibniz' vis viva (mv2). * Department of History of Science and Medicine, Yale University, New Haven, Conn. This work was supported by Public Health Service fellowship 5-F3-MH-24, 871-02 (SRP) from the National Institute of Mental Health. 1 The references in the following outline to frequency ofthemes are based on a detailed study of twenty-three historical accounts. The content ofthis outline is based on a selection from these accounts [I-IO]. 602 Stanley W.Jackson · Concept ofEnergy Perspectives in Biology and Medicine · Summer 1967 Regularly mentioned are the conception ofheat as a material substance, caloric, and its putative interference with scientific progress. Sometimes reference is made to the alternative view that heat was a form or a manifestation of motion, and it is suggested that this was the precursor of a sounder theory ofheat. The discussion ofheat usually leads to developmental accounts of the establishment of the mechanical equivalent of heat and ofhow the interconvertibility ofheat and motion was generalized to give the principle ofthe conservation ofenergy. It is commonly reported that these various interconvertible "forces" gradually came to be designated as energy (now \mv2) as distinct from Newtonian force (mass X acceleration). It is characteristic to extend these narratives to include the late-nineteenth-century developments in thermodynamics and electromagnetism. Some ofthese accounts refer to the field ofengineering and the development of the concept of work (force X distance) as significant in the evolution of the concept of energy. Kuhn [4] lays specific emphasis on this area; he indicates that the development of the theory of machines was the context for an "explicit formulation of the conservation law in terms of the equality of work done and kinetic energy created" [4, p. 332], and he points out that the majority of those who succeeded in quantifying conversion processes belonged to an engineering tradition either by training or by practice. The interconvertibility of heat and work, as well as that of heat and motion, is spoken of by others as the base from which the energy-conservation principle was generalized. Occasionally there is mention ofthe development ofthe steam engine as important in a different sense. The mercantile need to be able to compare the steam engine's power with other sources ofpower, for purposes ofcomputing costs and charges, is suggested as a significant factor in the emergence of the concept of energy. Rosen associates this theme with the point that "concept formation [in science] is determined not only by technical and scientific knowledge, but also by social environment and intellectual milieu" [8, p. 244]. Although attention to sociocultural influences indicates that this concept is no longer being viewed solely in terms of the "internal" history of science, none of...