Joseph Priestley as an heir of Newton

ABSTRACT

Like most Enlightenment philosophers, Priestley acknowledges his debt to Newton. However, despite his mentor’s prohibition against “making hypotheses”, in the 1770s, he embarked on a surprising metaphysical epic that led him, the theologian and scientist, to develop in his Disquisitions a bold system that articulated materialism, necessity and Socinianism. This synthesis constitutes the originality of a thinker who wanted to reapprehend science, metaphysics and theology together at the very moment when their dispersion seemed inevitable (and to give them an educational and political extension). It is based on a monistic ontology to which Priestley did not hesitate to give the unexpected name of materialism, at the risk of a number of misunderstandings, while he claims, much to the dismay of Reid, to closely follow the method of Newton. This paper will focus on the relation between Priestley and Newton’s ambiguous inheritance. What is Priestley’s “science” made of? What is its relationship to Newton and his “rules”, to mathematics, to the theory of language, to the so-called “analysis and synthesis method”, to Boscovich? How important is his claim for hypotheses and metaphysics? If Priestley indeed was a Newtonian, he surely was an unorthodox one.