Rejoinder to Gillispie, Lindberg, and Shea

16 Historically Speaking · September/October 2006 Rejoinder to Gillispie, Lindberg, and Shea Peter Harrison Let me first thank my respondents for their thought-provoking contributions. I am pleased to be in such illustrious company. I am also pleased that we seem to be in general agreement about the value of Butterfield's contribution and the importance of retaining the category the "Scientific Revolution," albeit with some caveats. William Shea provides a useful reminder of the importance for this revolution of such things as scientific instruments and the printing press. Indeed, Shea offers a gende corrective to my somewhat intellectualized account of the changes that took place in the sciences of this period. Whereas I pointed largely to conceptual revolutions and the reasons for them, he has righdy shown that material factors played a pivotal role in the production of the new forms of knowledge. Shea also highlights the importance of a new emphasis on the mastery of nature, to which I shall return at the end of this rejoinder. There are several other matters raised in the responses on which we might engage in profitable discussion. However, I shall restrict myself to two of the more important, raised in the main by David Lindberg and Charles Gillispie. These are, first, the issue of the putative separation of natural philosophy and mathematics in medieval science and, second , the question of whether concern with the early modern conception of "science" is largely a matter of semantics. Lindberg disagrees with my contention that natural philosophy and mathematics operated as two distinct disciplines until the 17th century. This criticism is pertinent to our present discussion insofar as it relates to an increasingly common view that what was distinctive (or "revolutionary") about early modern physics was its mathematical character . This issue has been the subject of an amicable disagreement between myself and Lindberg that extends beyond this forum. I must say that I am increasingly inclined to believe that Lindberg has a point, and that at the very least his objections warrant further investigation. My own view is consistent with a body of influential secondary literature and also relies on the formal classifications of the sciences that we encounter in the medieval and Renaissance texts. These do seem to support an important distinction between mathematical sciences and natural philosophy, with only the latter understood as providing true causal accounts of natural Si phenomena. This distinction also explains the special status of the so-called "mixed mathematical sciences." Yet whether the relevant practitioners were themselves inclined to observe these distinctions is another matter entirely, and it may be that in practice these formal distinctions were simply ignored . After all, it is not clear that practicing scientists of any era have conformed to the theoretical accounts of scientific activity provided by philosophers of science. Certainly, I have no grounds for While it is important not to quibble about the meaning ofwords ifnothing hangs on the outcome, I do believe that attending to the way in which historicalactors usedsuch terms as "science33and "naturalphilosophy has importantpayoffsfor the historian. disputing Lindberg's claim that those medieval thinkers concerned with optics dealt with both mathematical and physical aspects of the relevant phenomena. That said, there does seem to have been a longstanding convention according to which certain astronomical models had value by virtue of the fact that they saved the phenomena while not necessarily being true accounts of physical reality. This can perhaps be traced to Thomas Aquinas's attempt to square Ptolemy's mathematical astronomy and its eccentrics and epicycles with Aristode's natural philosophy and its homocentric spheres. Aquinas declared that the former was not necessarily true. Although it was consistent with appearances, the phenomena could be saved in some other way not yet understood. This stance seems to be invoked again in Osiander's infamous preface to Copernicus 's De Revolutionibus, where the heliocentric hypothesis is described as "a calculus that fits the observations" although again "not necessarily true." The principle appears again in Galileo's equally infamous (and disingenuous) disclaimer at the end of the Dialogue concerning the Two Chief World Systems.' It is also suggestive, as I noted in my original article, that Kepler seems to...