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.

PA See APPENDIX OF SPECIAL SYMBOLS.

Pa See WANG, PA.

Pacifism, (1) opposition to war, usually on moral or religious grounds,...

Paine Thomas (1737–1809), American political philosopher, revolutionary defender of democracy and...

Paley William, (1743–1805), English moral philosopher and theologian. He was born...

Panaetius See STOICISM.

Panentheism See KRAUSE, PANTHEISM.

Panlogism See HEGEL.

Panpsychism the doctrine that the physical world is pervasively psychical, sentient...

Pantheismusstreit (German, 'dispute over pantheism'), a debate primarily between the German...

Paracelsus pseudonym of Theophrastus Bombastus von Hohenheim (1493–1541), Swiss chemist, physician,...

Paraconsistency the property of a logic in which one cannot derive...

Paradigm as used by Thomas Kuhn (The Structure of Scientific Revolutions,...

Paradigm case argument an argument designed to yield an affirmative answer to the...

Paradox a seemingly sound piece of reasoning based on seemingly true...