Atoms and Powers: An Essay on Newtonian Matter-Theory and the Development of Chemistry (review)

BOOK REVIEWS 95 Mr. Curley has written a challenging and controversial book, and on three issues the reviewer had to record his disagreement with the author's position. Nevertheless he found his work interesting throughout, informative and well argued. It deserves a lasting place among Spinozistic scholarship. PAUL SELIGMAN University oJ Waterloo Atoms and Powers: An Essay on Newtonian Matter-Theory and the Development of Chemistry. By Arnold Thackray. (Cambridge, Mass.: Harvard University Press, 1970) "The two major problems confronting any philosophy of chemistry have always been to decide on the units that endure through chemical change, and on the terms in which the causes of that change might be discussed" (p. 199). The chemist in the eighteenth century faced these two fundamental problems--that of deciding what was to be considered an element and that of deciding on the ultimate terms of explanation for chemical phenomena--in rather explicit terms. Boyle and the mechanical philosophers of the late seventeenth century had reopened the question of the elements by rejecting the traditional four-element (earth, water, air, fire) and three-principle (salt, sulphur, mercury) theories and suggesting that there might not exist elementary substances in the traditional sense at all. These same mechanical philosophers sought to reduce chemistry to a branch of physics by attempting to explain away the chemical properties of matter solely in terms of the primary, physical properties which they believed matter to possess. In his book, Atoms and Powers, Thackray discusses the influence of Newtonianism on the eighteenth-century discussions of these problems. In the process, he adds some order and insight to what may mildly be described as a confused and only partly charted period of the history of science. Newton's reputation and ideas had a profound influence on almost every area of eighteenth-century science. In relation to chemistry, "Newtonianism" meant two things in the eighteenth century: (I) a belief in the "inertial homogeneity" of matter, and consequently in a highly porous and internally ordered structure to all known substances ; and (2) a belief that for chemistry, as for the other physical sciences, the route to an ordered, quantified, predictive science lay through the measurement of forces, in this case the forces of chemical affinity (p. 5). Thackray argues rather convincingly that Newtonianism was not in general a progressive trend for eighteenth-century chemistry, that quantitative and successfully predictive chemistry---culminating in the works of Lavoisier, Dalton, and others----came less from the Newtonian, reductionist approach than from a holistic approach which acknowledged the chemical Ievel of organization and sought generalizations in chemistry from empirical study of the phenomenal properties of chemical substances. The eighteenth-century chemist needed to learn about the chemical properties of matter before he could explain them in terms of Newtonian physics. Aside from the intrinsic interest of Thackray's book as an historical study, he raises several issues which should be of particular interest to readers of the Journal of the History o] Philosophy. First, he implicitly reveals the important difference between the historical and logical reconstructions of a science. A twentieth-century philosopher of science might rightfully discuss the significance of the reductionist approach to chemistry and the importance of measuring inter-particulate forces to the understanding 96 HISTORY OF PHILOSOPHY of chemical fact. History, however, need not follow a logical sequence; and the Newtonian trend, which might seem remarkably progressive to twentieth-century eyes, did not solve the basic problems facing the eighteenth-century chemist. It is more than slightly ironic that chemistry gained much of its order from a return to the premechanical view of elements as the bearers of qualities in chemical reactions. Secondly, Thackray's discussion casts considerable light on the subtle and fascinating problem of the nature of scientific change. His close analysis of Newtonianism and chemistry provides much-needed historical fuel for the discussion of the role of the paradigm in the development of science, "paradigm" taken in both the sociological and conceptual senses. Finally, an historian of philosophy would find this book useful in illustrating the scientific context of many important problems that arose in eighteenth-century philosophy, particularly problems concerning the nature of matter, the breakdown of the distinction...