Meinong's jungle

Meinong's jungle is the name given to the repository of non-existent entities in the ontology of Alexius Meinong.

Meinong, an Austrian philosopher active at the turn of the 20th century, believed that since non-existent things could apparently be referred to, they must have some sort of being, which he termed sosein ("being so"). A unicorn and a pegasus are both non-being; yet it's true that unicorns have horns and pegasi have wings. Thus non-existent things like unicorns, square circles, and golden mountains can have different properties, and must have a 'being such-and-such' even though they lack 'being' proper. The strangeness of such entities led to this ontological realm being referred to as "Meinong's jungle". The jungle is described in Meinong's work Über Annahmen (1902). The name is credited to William C. Kneale, whose Probability and Induction (1949) includes the passage "after wandering in Meinong's jungle of subsistence … philosophers are now agreed that propositions cannot be regarded as ultimate entities".

The Meinongian theory of objects (Gegenstandstheorie) was influential in the debate over sense and reference between Gottlob Frege and Bertrand Russell which led to the establishment of analytic philosophy and contemporary philosophy of language. Russell's theory of descriptions, in the words of P.M.S. Hacker, enables him to "thin out the luxuriant Meinongian jungle of entities (such as the round square), which, it had appeared, must in some sense subsist in order to be talked about". According to the theory of descriptions, speakers are not committed to asserting the existence of referents for the names they use.

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