Of all the doctrines of Tlon, none has caused more uproar than materialism. Some thinkers have formulated this philosophy (generally with less clarity than zeal) as though putting forth a paradox. In order to make this inconceivable thesis more easily understood, an eleventh-century heresiarch conceived the sophism of the nine copper coins, a paradox as scandalously famous on Tlon as the Eleatic aporiae to ourselves. There are many versions of that “specious argument,” with varying numbers of coins and discoveries; the following is the most common:

On Tuesday, X is walking along a deserted road and loses nine copper coins. On Thursday, Y finds four coins in the road, their luster somewhat dimmed by Wednesday’s rain. On Friday, Z discovers three coins in the road. Friday morning X finds two coins on the veranda of his house.

From this story the heresiarch wished to deduce the reality—i.e., the continuity in time—of those nine recovered coins. “It is absurd,” he said, “to imagine that four of the coins did not exist from Tuesday to Thursday, three from Tuesday to Friday afternoon, two from Tuesday to Friday morning. It is logical to think that they in fact did exist—albeit in some secret way that we are forbidden to understand—at every moment of those three periods of time.”
The language of Tlon resisted formulating this paradox; most people did not understand it. The “common sense” school at first simply denied the anecdote’s veracity. They claimed it was a verbal fallacy based on the reckless employment of two neologisms, words unauthorized by standard usage and foreign to all rigorous thought: the two verbs “find” and “lose,” which, since they presuppose the identity of the nine first coins and the nine latter ones, entail a petitio principii. These critics reminded their listeners that all nouns (man, coin, Thursday, Wednesday, rain) have only metaphoric value.

-Tlon, Uqbar, Orbis Tertius, Jorge Luis Borges (1941).

The other creature engendered by the problem of knowledge is Lotze's "hypothetical animal." More solitary than the statue that smells roses and at last becomes a man, this animal has but one sensitive spot on its skin, on the end of an antenna and therefore movable. The structure of this animal prevents it, as one can see, from receiving simultaneous perceptions, but Lotze believed that the ability to retract or project its sensitive antenna was enough to allow the all-but-isolated animal to discover the outside world (without the aid of Kantian categories) and to perceive the difference between a stationary object and a mobile one. Vaihinger admired this fiction; it is contained in the work titled Medizinische Psychologie, published in 1852.

--the Book of Imaginary Beings, Jorge Luis Borges (1967)

In that Empire...

In that Empire, the Art of Cartography attained such Perfection that the map of a single Province occupied the entirety of a City, and the map of the Empire, the entirety of a Province. In time, those Unconscionable Maps no longer satisfied, and the Cartographers Guilds struck a Map of the Empire whose size was that of the Empire, and which coincided point for point with it. The following Generations, who were not so fond of the Study of Cartography as their Forebears had been, saw that that vast Map was Useless...

-- "On Exactitude in Science" (1946), Jorges Luis Borges

Menard’s fragmentary Quixote is more subtle than Cervantes’. Cervantes crudely juxtaposes the humble provincial reality of his country against the fantasies of the romance, while Menard chooses as his “reality” the land of Carmen during the century that saw the Battle of Lepanto and the plays of Lope de Vega. What burlesque brushstrokes of local color that choice would have inspired in a Maurice Barres or a Rodriquez Larreta! Yet Menard, with perfect naturalness, avoids them. In his work, there are no gypsy goings-on or conquistadors or mystics of Philip IIs or autos da fe. He ignores, overlooks—or banishes—local color. That disdain posits a new meaning for the “historical novel.” That disdain condemns Salammbo, with no possibility of appeal.

--Pierre Menard, Author of the Quixote, Jorge Luis Borges (1941).

Those who have insinuated that Menard devoted his life to writing a contemporary Quixote besmirch his illustrious memory. Pierre Menard did not want to compose another Quixote, which surely is easy enough—he wanted to compose the Quixote. Nor, surely, need one be obliged to note that his goal was never a mechanical transcription of the original; he had no intention of copying it. His admirable ambition was to produce a number of pages which coincided—word for word and line for line—with those of Miguel de Cervantes.
“My purpose is merely astonishing,” he wrote me on September 30, 1934, from Bayonne. “The final term of a theological or metaphysical proof—the world around us, or God, or chance, or universal Forms—is no more final, no more uncommon, than my revealed novel. The sole difference is that philosophers publish pleasant volumes containing the intermediate stages of their work, while I am resolved to suppress those stages of my own.” And indeed there is not a single draft to bear witness to that years-long labor.

--Pierre Menard, Author of the Quixote, Jorge Luis Borges (1941).