“Natural philosophy” is often used by historians of science as an umbrella term to designate the study of nature before it could easily be identified with what we call “science” today. This is done to avoid the modern and potentially anachronistic connotations of the term “science.” But “natural philosophy” (and its equivalents in different languages) was also an actor’s category, a term commonly used throughout the early modern period and typically defined quite broadly as the study of natural bodies. As the central discipline dedicated to laying out the principles and causes of natural phenomena, natural philosophy underwent tremendous transformations during the early modern period. From its medieval form as a bookish Aristotelian discipline institutionalized in the universities, natural philosophy became increasingly associated during the sixteenth and seventeenth centuries with new authorities, new practices, and new institutions, as is clear from the emergence of new expressions such as the “experimental natural philosophy” of Robert Boyle (1627–1691) and the Royal Society of London or the Philosophiae naturalis principia mathematica (Mathematical Principles of Natural Philosophy, 1687) of Isaac Newton (1642–1727).
Traditional natural philosophy (that is, of the bookish, largely Aristotelian variety) continued to prevail in university teaching through much of the seventeenth century (see Grafton, Chapter 10, this volume), but it, too, was transformed by the innovations of the period, which prompted attempts at adaptation as well as staunch resistance. By 1700, it had yielded definitively in all but the most conservative contexts to the mechanical, mathematized natural philosophies of Cartesianism and Newtonianism.