Editing Tlön, Uqbar, Orbis Tertius (section)

===Philosophical themes===
Through the vehicle of [[fantasy]] or [[speculative fiction]], this story playfully explores several [[philosophy|philosophical]] questions and themes. These include, above all, an effort by Borges to imagine a world (Tlön) where the 18th century philosophical [[subjective idealism]] of [[George Berkeley]] is viewed as [[common sense]]<ref>{{cite journal|journal=[[Philosophy and Literature]] |volume=1 |issue=3 |date=Fall 1977 |pages=337–341 |title='..Merely a Man of Letters': an interview with Jorge Luis Borges |last1=Dutton |first1=Denis |author-link1=Denis Dutton |last2=Palencia-Roth |first2=Michael |last3=Berkove |first3=Lawrence I. |doi=10.1353/phl.1977.0016 |s2cid=170118915 |display-authors=1 |url=http://denisdutton.com/jorge_luis_borges_interview.htm |access-date=2015-01-12}} In the interview, Dutton refers to Tlön as "A world in which Berkeley is common sense instead of Descartes". Borges concurs.</ref> and "the doctrine of [[materialism]]" is considered a heresy, a scandal, and a paradox.<ref>"Tlön...", p.117</ref> Through describing the languages of Tlön, the story also plays with the [[Sapir–Whorf hypothesis]] (also called "linguistic relativism")—the [[epistemology|epistemological]] question of how language influences what thoughts are possible. The story also contains several metaphors for the way ideas influence reality. This last theme is first explored cleverly, by way of describing physical objects being willed into existence by the force of imagination, but later turns darker, as fascination with the idea of Tlön begins to distract people from paying adequate attention to the reality of [[Earth]].

Much of the story engages with the philosophical idealism of George Berkeley, who questioned whether it is possible to say that a thing exists if it is not being perceived. (Berkeley, a philosopher and, later, a bishop in the Protestant Church of Ireland, resolved that question to his own satisfaction by saying that the omnipresent perception of [[God]] ensures that objects continue to exist outside of personal or human perception.) Berkeley's philosophy privileges perceptions over any notion of the "thing in itself." [[Immanuel Kant]] accused Berkeley of going so far as to deny [[objective reality]].

In the imagined world of Tlön, an exaggerated Berkeleyan idealism ''without God'' passes for common sense. The Tlönian recognizes perceptions as primary and denies the existence of any underlying reality. At the end of the main portion of the story, immediately before the postscript, Borges stretches this toward its logical breaking point by imagining that, "Occasionally a few birds, a horse perhaps, have saved the ruins of an amphitheater" by continuing to perceive it.<ref name="tlon119">"Tlön…", p.119</ref> Besides commenting on Berkeley's philosophy, this and other aspects of Borges's story can be taken as a commentary on the ability of ideas to influence reality. For example, in Tlön there are objects known as ''hrönir''<ref name="tlon119" /> that arise when two different people find the "same" lost object in different places.

Borges imagines a Tlönite working his way out of the problem of [[solipsism]] by reasoning that if all people are actually aspects of one being, then perhaps the [[universe]] is consistent because that one being is consistent in his imagining. This is, effectively, a near-reconstruction of the Berkeleyan God: perhaps not omnipresent, but bringing together all perceptions that do, indeed, occur.

This story is not the only place where Borges engages with Berkeleyan idealism. In the world of Tlön, as in Borges's essay ''[[New refutation of time]]'' (1947), there is (as [[Emir Rodríguez Monegal]] and [[Alastair Reid (poet)|Alastair Reid]] comment) a "denial of space, time, and the individual I."<ref>Monegal and Reed, notes to ''Borges, a Reader'', p. 353.</ref>  This worldview does not merely "bracket off" objective reality, but also parcels it separately into all its successive moments. Even the continuity of the individual self is open to question.

When Borges writes "The [[metaphysics|metaphysicians]] of Tlön are not looking for truth or even an approximation to it: they are after a kind of amazement. They consider metaphysics a branch of fantastic literature,"<ref>"Tlön…", p.116</ref> he can be seen either as anticipating the extreme [[relativism]] that underlies some [[postmodernism]] or simply as taking a swipe at those who take metaphysics too seriously.