Objective reference in Judgments, [74]–6.
Obverse, [133].
Obversion of Propositions, [133], 4; how affected by the existential import of propositions, [223]–7; of hypothetical propositions, [269]; of complex propositions, [488], 9.
Obvertend, [133].
Octagon of Opposition, [144].
Opposition of Complex Terms, [470]–2.
Opposition of Propositions, [109]–19; illustrated by Euler’s diagrams, [160]; how affected by the existential import of propositions, [227]–31; of modal propositions, [231], 2; of conditional propositions, [256]–8; of hypothetical propositions, [264]–8; of complex propositions, [478]; of compound propositions, [480].
Or, its logical signification, [469].
Ostensive Reduction, [318].
Partial Identities, [192].