Index of Logic Articles - O

O

Object language -- Object of the mind -- Object theory -- Occam's razor -- On Formally Undecidable Propositions of Principia Mathematica and Related Systems -- One-sided argument -- Ontological commitment -- Open sentence -- Opinion -- Opposing Viewpoints series -- Ordered logic -- Organon -- Original proof of Gödel's completeness theorem -- Osmund Lewry -- Ostensive definition -- Outline of logic -- Overbelief -- Oxymoron --