Isaac Newton, Interdisciplinarian: Newton's cross-domain evidential reasoning

Abstract

This paper argues that Newton employed a non-hypothetical method of evidential reasoning called demonstrative induction in his chronological studies. In demonstrative induction, inductive risk is confined to the premises, and the secureness of the conclusion depends on the secureness of those premises. I show that Newton's approach to chronology exemplifies two key restrictions on demonstrative induction: (i) premises must themselves be supported by demonstrative induction or by inductive generalizations, and (ii) inductive risk should be confined to premises drawn from domains of inquiry whose claims are better established, thereby “exporting” inductive risk to more certain domains. Drawing on Newton's use of sources from history, biology, social science, and astronomy, I analyze how he transformed data from these fields into evidence for his chronological scheme. The strategy of exporting inductive risk, I argue, reveals a common evidential pattern across his natural-philosophical, historical, and theological work, and sheds light on the deeper methodological unity that underlies his otherwise disparate intellectual pursuits.