The article surveys and contextualizes the main arguments among philosophers and academic physicians surrounding the status of physiognomy as a valid science from the thirteenth to the early sixteenth centuries. It suggests that despite constant doubts, learned Latin physiognomy in the later Middle Ages was recognized by natural philosophers (William of Spain, Jean Buridan, William of Mirica) and academic physicians (Rolandus Scriptor, Michele Savonarola, Bartolomeo della Rocca [Cocles]) as a body of knowledge rooted in a sound theoretical basis. Physiognomy was characterized by stability and certainty. As a demonstrative science it was expected to provide rational explanation for every bodily sign. In this respect, learned physiognomy in the Middle Ages was dramatically different from its classical sources, from Islamic and possibly from early-modern physiognomy as well.