original position See LIBERALISM, RAWLS.

Orpheus See ORPHISM.

Orphism a religious movement in ancient Greece that may have influenced...

Ortega y Gasset José (1883–1955), Spanish philosopher and essayist. Born in Madrid, he...

ostensive definition See DEFINITION.

Ostwald, Wilhelm See ENERGETICISM.

other minds, problem of See PROBLEM OF OTHER. MIND.

ought–is problem See FACT – VALUE DISTINCTION.

ousia ancient Greek term traditionally translated as 'substance'. Formed from the...

outer converse See CONVERSE, OUTER AND INNER.

outer domain semantics See FREE LOGIC.

overdetermination See CAUSATION.

overman See NIETZSCHE.

overriding reason See REASONS FOR ACTION.

Oxford Calculators a group of natural philosophers, mathematicians, and logicians who flourished...

Oxford philosophy See ANALYTIC PHILOSOPHY.

Oxford school of intuitionism See PRICHARD.