 Medieval and Renaissance notions of probability largely derived from the same ancient sources and remained related to each other through interchanges between scholastics and humanists. Yet soon after 1500, pre-modern probability discourse began to assume a new shape. Although the many differences between medieval and early modern scholastic and humanist uses of “the probable” cannot be summarized here, they should not be underestimated. Above all, at the end of the sixteenth century, the Aristotelian endoxon gave way in moral theology to a two-tiered definition of probability as either intrinsic (based on known reasons) or extrinsic (based on the opinions of others). How much such innovations fostered the rise of numerical probability in the middle of the seventeenth century is still largely an open question. Knebel (2000) and Schuessler (2019) show that it is reasonable to assume a significant contribution by early modern scholasticism. Maryks (2008) claims that the humanist precedent prompted the Jesuits to introduce the distinction between internal and external probability. At present, however, the cross-pollinations between early modern humanism and scholasticism are scarcely better understood than the developments leading to the invention of numerical probability.