This contribution, in two parts, addresses a long-standing problem in the history of geology: Was the geological theory of James Hutton derived inductively from observations and scientific knowledge, or was it derived a priori as a speculative system? Hutton’s own writings do little to clarify the question, and the conflict in interpretations has remained at an impasse. This contribution proposes to resolve that conflict by focusing on the two years Hutton spent as a young man studying chemistry in Paris. I argue that Hutton studied with one of the great chemistry teachers of the eighteenth century, Guillaume-François Rouelle, and that Rouelle’s teachings provided the foundations of Hutton’s geological theory.
Part One of this contribution reviewed evidence that Hutton was a student of Rouelle’s, and concluded with a high degree of confidence, but less than certainty, that Hutton did study with Rouelle. In this Part Two, it is argued that Hutton adopted almost all the geological ideas found in Rouelle’s lectures. This Part Two also proposes a reconstruction of the development of Hutton’s cyclical model of Earth strata, taken as the starting point of his broader theory, to show that it developed from observations and inductions, and his study with Rouelle, and was not developed as an a priori system. That conclusion will require a new interpretation of Hutton’s theory, which should now be understood as part of a continuum of geological knowledge developing during the eighteenth century.