Hearing, Assenting, and Acting: Later Medieval Accounts of Testimonial Belief and Knowledge, 1300-1550

This project is a comprehensive study of epistemological discussions on testimonial belief and knowledge in the Later Middle Ages (13001550), a period that has gone unnoticed in the history of epistemology. The project will proceed in three stages. The first stage will be devoted to identifying predecessors whose views had great influence on later medieval epistemology of testimony. Special attention will be paid to Augustine (354-430), Avicenna (970-1037), Averroes (1126-1198), and Thomas Aquinas (1225-1274). The second stage focuses on later medieval accounts of testimonial belief, a voluntary inevident assent to what one hears. After analyzing three different aspects of testimonial belief, namely, the epistemic, practical, and moral aspect, the central issues and debates concerning each aspect will be examined with works of John Duns Scotus (1266-1308), William Ockham (1285-1347), and so on. The last stage focuses on testimonial knowledge, an involuntary evident assent to what one hears. It will be examined how some later medieval philosophers, e.g., John Buridan (1300-1361), John Gerson (1363-1429), and John Major (1470-1550), explain the possibility of testimonial knowledge and the three different aspects of it with the notion of moral certainty (certitudo moralis), a type of certainty that is sufficient for testimonial knowledge and morally good action.