Tlönian

Tlönian is an adjective and noun relating to Tlön, the fictional planet and culture described in Jorge Luis Borges’s short story Tlön, Uqbar, Orbis Tertius (1940). In the story, a secret society called Orbis Tertius fabricates Tlön as an entirely constructed reality, whose inhabitants, languages, and customs gradually influence Earth’s own perceptions of reality.

Tlönian thought is rooted in philosophical idealism: the world is organized by language and perception, and physical objects gain or lose apparent existence through naming and description. Tlön’s languages are depicted as highly structured and capable of shaping thought, with concepts such as time, space, and causality not being absolute but contingent on linguistic frameworks. The Tlönian project extends from language into knowledge, memory, and even the calendar and ontology of Earth.

In the narrative, Tlönian materials begin to permeate Earth as encyclopedic works and texts circulate, prompting a gradual transformation of Earth’s own worldview. This blending of Tlön with Earth raises questions about the relationship between language and reality and challenges assumptions about objectivity and existence.

Today, Tlönian can denote anything pertaining to Tlön’s culture, language, or philosophy, or more generally a fictive, language-driven worldview. The term is frequently discussed in literary and philosophical contexts as an exemplar of linguistic relativity and metafiction, illustrating how constructed language and concepts can shape perception and reality. See also Tlön, Uqbar, Orbis Tertius; Borges; philosophy of language.