 There are two different ways in which an evaluator can consider a proposition as more probable and a counter-proposition as probable at the same time. First, the evaluator can believe that more and/or better experts hold x true than y, although y is approved by a sufficient number of experts to count as  probable.[37]  Second, the evaluator may consider a proposition as more probable according to her own weighing up of the reasons, while the counter-proposition is considered probable because it is the opinion of many or weighty  experts.[38]  Both options show that there is no obvious logical problem with the assumption that two incompatible propositions can both be regarded as rationally  affirmable.[39]  This does not, however, invalidate the claim that only one of the propositions can be rationally affirmed at a given time and by a given person from her own standpoint. The person in question can, it seems, only rationally affirm what she regards as more probable than its negation. Consequently, regarding a rival opinion as probable means considering it as affirmable by others – or, in modern terminology, by one’s epistemic  peers.[40]  This insight is an important step towards opinion pluralism and the conceptualization of reasonable disagreement, and it is significant that it is in nuce implied in the both-sided probability of medieval scholastics.