 Pre-modern probability was not a number or ratio, but mainly a binary property which a proposition either had or did not have. Yet pre-modern probability was also an ordinal concept. Some propositions were regarded as more probable (probabilior, probabilius) than others. More probable opinions were a subclass of probable opinions. Consequently, an opinion had at least to be probable in order to be more probable than another opinion. In line with these premises, strict order relations (i.e. “&gt;” and “&lt;”) for opinions were common in medieval and Renaissance philosophy. Interestingly, ascriptions of equal probability seem to be rare before the sixteenth century (see Schuessler 2016). An equal balance of reasons gave rise to doubt (dubium). The moral rules for decisions in doubt, however, were different from those for the choice between probable opinions. Hence, doubt should not straightforwardly be equated with equal probability, in particular in medieval scholasticism. Further research is needed to uncover the role of equi-probability in the period 1200–1500; until then, we can only be sure that in this period the possibility of a strict ordering was envisaged for probabilities.