Nature and Motion in the Middle Ages by Fr. James A. Weisheipl (review)

BOOK REVIEWS 381 Nature and Motion in the Middle .Ages. By FR. JAMES A. WEISHE,IPL. Edited by William E. Carroll. Studies in Philosophy and the History of Philosophy, v. 11. Washington, D.C.: The Catholic University of American Press, 1985. Pp. xii + 292. In this book the editor brings together some articles previously published by Fr. James Weisheipl which deal with various questions relating to Aristotle's natural philosophy along with some medieval interpretations , mainly by St. Thomas Aquinas. The volume was not originally intended to be a posthumous offering, but Fr. James's untimely death has made it into one, and the editor provides a warm ' In Memoriam' at the end. During his fruitful scholarly career in medieval studies Weisheipl devoted much of his efforts to correcting what he took to be some basic modern misunderstandings of Aristotelian and medieval natural philosophy . A long-standing and still commonly held view has it that modern science became possible only after a total and unequivocal rejection of Aristotle's understanding of physical science. According to this theory, science as we now understand it appeared only in the seventeenth century. which is to say long after the close of the Middle Ages (pp. 261 ff.) and therefore, apart from purely historical interest, there remains nothing to be gained from a study of the medieval view of science. In the last century, however, Pierre Duhem argued that heretofore unrecognized linkages exist between modern science and the much earlier efforts by Aristotle and his medieval interpreters. Following Duhem's pioneering work, more recent scholarship has increased still further our knowledge of the relationship between early and modern science, with some (e.g. A. Maier) emphasizing elements of discontinuity and others (e.g. Weisheipl ) pointing out some long neglected but nonetheless philosophically sound and therefore still valuable insights of Aristotle and his medieval disciples. Weisheipl argues that the Aristotelian/medieval notion of nature is perfectly compatible with what he terms the physico-mathematical approach so profitably adopted by modern science. (ch. 11) He rejects the idea that the scientist, after the weleome advances of men like Galileo and Newton, is henceforward correct in replacing the earlier concept of nature with a purely mechanistic model of the universe. The more recent fruitful application of the physico-mathematieal method in science, far from requiring the rejection of Aristotle's concept of nature in favor of a nature-less mechanical model, finds a needed complimentarity with its inclusion as a sure foundation. Taking Aristotle's lead, Albert the Great, Aquinas, and others in fact, Weisheipl argues, were quite well aware of 38~ BOOK REVIEWS the more mathematically grounded method in studying nature. The work they did especially in astronomy, optics, and harmonics, W eisheipl points out, clearly reveals their belief in the heuristic power of mathematics. He readily admits that the earlier attempts to ' save the appearances ' with relatively primitive mathematical tools pale in comparison with the modern achievement, but he thinks the fundamental instinct so remarkably exploited by later scientists is already evident in earlier times. At the core of Weisheipl's exposition of Aristotelian/medieval science is the basic concept of nature, and the frequent failure of scholars to understand this concept conectly is, in his view, the major underlying reason for so much confusion. " For Aristotle . . . , v