Principles in early modern natural philosophy: a provisional taxonomy

Peter Anstey

Univeristy of Sydney

The term ‘principle’ is almost ubiquitous in early modern natural philosophy and yet its semantic range is enormously varied. There are principles of nature, principles of matter, chymical principles, seminal principles, laws of nature as principles, foundational principles, explanatory principles, principles of mechanics, principles of hydrostatics, and so on. A measure of the importance of the notion is the fact that the term appears in the titles of many books on natural philosophy from the period, most famously in Descartes’ Principia philosophiae and Newton’s Principia. This paper provides a survey of the use of the term ‘principle’ and related notions in natural philosophical writings spanning from Francis Bacon to the mid-eighteenth century. This is with a view to developing a provisional taxonomy of the sorts of principles that were appealed to and deployed in scientific writings from the period. It argues that there is a natural fault-line between what are styled ontological principles, such as seminal principles and the principles of matter, and epistemic principles that normally appear in propositional form. It is also argued that throughout the period there are some significant developments in the manner in which the term was used and that these developments give us some insight into what can best be described as shifts in the foundations of early modern philosophy of science.