 Bolzano developed a particular logic for ought propositions which — without today’s formalism — comes already close to modern deontic logic in certain respects. The primitive form of an ought proposition is \([A\) — has — an ought of \(X]\) or, more accurately, \([A\) — has — an ought to will to do \(X]\) (WL II, 70; slightly different in RW I, 228). The concept [ought] is simple (WL II, 69, WL IV, 489), but its usage underlies certain principles stated explicitly by Bolzano: