This essay argues that techniques for assessing testimonial credibility were well established in English legal contexts before they appeared in English natural philosophy. ‘Matters of fact’ supported by testimony referred to human actions and events before the concept was applied to natural phenomena. The article surveys English legal views about testimony and argues that the criteria for credible testimony in both legal and scientific venues were not limited to those of gentle status. Natural philosophers became concerned with testimony when they (...) shifted their attention from universal statements about nature to particular natural and experimental events. Testimony thus became important in the construction of natural and experimental histories constructed by English naturalists. The shift to a more Baconian approach to natural investigation, itself shaped in part by legal concepts and practice, made it possible for members of the Royal Society to adopt an already familiar and societally approved approach to testimony. However, the essay also suggests how the use of scientific instruments and the desire to avoid the adversarial processes of the law modified legal conditions for fact determination, and made it possible for later generations to associate the concept of fact, supported by credible testimony, with the natural rather than the human sciences.Author Keywords: Natural history; Natural philosophy; Testimony; Credibility; Science and law. (shrink)