Ontological distinction

An ontological distinction is a distinction based on a difference in the way or mode of existence. Ontology is that branch of philosophy which studies questions regarding these modes of existence.

An example of an ontological distinction is the distinction between living persons and fictional characters of novels. A more important example is given by the mind-body dualism of Descartes: he claims that there are two disjoint realms of existence, the realm of the body and the realm of the mind.

See also: Ontological distinction(computer science).