 Bolzano combines his doctrine that the form \([A\) has \(b]\) is common to all propositions with a correspondence theory of truth, whereby he, like Aristotle, avoids speaking of correspondence or adequation. A proposition \([A\) has \(b]\) is true, according to Bolzano, iff \(A\) has (in fact) \(b\) (WL I, 112). There is an important qualification, however, that Bolzano has thereby in mind, namely that there is at least one \(A\); a proposition \([A\) has \(b]\) can only be true, according to Bolzano, if it is about something and if its subject idea \([A]\) is therefore non-empty (WL II, 16, 328–330, 399 ff.). Formulated more carefully, Bolzano’s truth condition must therefore be stated as follows (WL I, 112, 121–224, WL II, 26 f., 328–330):