 a) Explication of the Entailment Relation: In addition to logical consequence and probability, there is a third category, however, that is brought into play by Bolzano within this context: it is the relation which obtains between a set \(\sigma\) of propositions and a proposition \(s\) iff \(\sigma\) is the “objective ground” of \(s\) or — in other words — iff \(s\) “follows objectively” from \(\sigma\); in today’s terminology we say instead that \(\sigma\) entails \(s\) or that \(s\) is entailed by \(\sigma\). This relation of entailment (Abfolge) is — to be clear — primarily not an epistemological relation but — like (logical) consequence and (logical) probability — a relation between a set of propositions and a single proposition (WL II, 339 ff., WL III, 495 f.).