A note on equiprobability prior to 1500

Rudolf Schuessler has argued that sixteenth-century thinkers developed a concept of equal probability that was virtually absent before 1500 and that may have contributed to the birth of mathematical probability shortly after 1650. This note uses additional textual evidence to argue that the concept of equal probability was in fact generally available to medieval thinkers. It is true that ascriptions of equal probability are comparatively rare in medieval texts, but this can be explained without positing a conceptual blind spot.