Abstract
The recently much discussed phenomenon of testimony as a social source of knowledge plays a crucial justificatory role in Richard Swinburne's philosophy of religion. Although Swinburne officially reduces his principle of testimony to the criterion of simplicity and, therefore, to a derivative epistemic source, we will show that simplicity does not play the crucial role in this epistemological context. We will argue that both Swinburne's philosophical ideas and his formulations allow for a fundamental epistemic principle of testimony, by showing that Swinburne has already implicitly justified the use of testimony as an epistemic source via his fundamental a priori principle of credulity.