Isaac Newton Explicating His Natural Philosophical Method: A Study of the Development of the Methodological Statements in the Queries to the Opticks

In this essay, we document the development of five important methodological passages in Isaac Newton’s (1642-1727) Queries to the Opticks and explore some of the reasons why he continuously revised and reformulated them. The Queries have a complex and fascinating editorial history, appearing in both English and Latin forms. Here we analyse the extant manuscript material in relation to the published versions of Opticks (1704, 1717, 1721, and 1730) and Optice (1706 and 1719) and, additionally, to other relevant sources such as Newton’s ‘an account of the book called Commercium epistolicum’ and Cambridge University Library, add. ms. 3970, f. 479rv and f. 480v in which he addressed a number of principles of philosophy. More specifically, we analyse five passages in which Newton clarified his methodological views to his readers: in the first passage, he demarcated “the main Business of natural Philosophy” as arguing from phenomena without feigning hypotheses; in the second, he justified his frequent use of the word “attraction”; in the third, he briefly discussed under which conditions a property, especially hardness, can be considered universal; in the fourth, he defended his own method by refuting the view that gravity and other active principles are “occult Qualities”; and, finally, in the fifth, he described his own method in terms of analysis and composition (or synthesis). Based on our analyses of these passages, we are able to trace Newton’s changing methodological ideas from the early 1700s to 1717. Furthermore, we uncover how the erstwhile natural philosophical debates informed his writing of the Queries and what passages acted as precursors to his famous regulae philosophandi.