I stopped reading it…
…oops. 
Tlön, Uqbar etc.
[spoiler]Time for illustrating those languages, yes? Yes. 
At first I wanted to provide you guys with a propædeutic to the ideas presented by Borges in this story. But then I realise that would easily become one of the most boring posts in the history of my posting, and that no-one wants a propædeutic, even without knowing that word means. So I decided a good post to help ideas flow would be an application of “Tlön, Uqbar etc”. Because the Tlönian languages — believe it or not — do exist in one way or another in the world. There are two flavours of Tlönian languages in the story: strictly verbal, and strictly adjective.
Strictly verbal languages are funny birds. While, theoretically, they would be the most probable kind of minimalistic language to exist, there are no natural languages of such kind. I say they’re probable based on the idea that all gramatical categories can be simulated by verbs. An adjective, like “orange”, can be substituted by the verb “to be orange”. Any adverb can be converted into an auxiliary verb: “quickly” would be substituted with some broader distant cousin of “to rush”. And so on: “upward behind the onstreaming it mooned.”
Still. Perhaps the closest parallel to a strictly verbal language we have, as far as I know, is mathematics. Maths are an interesting kind of language. It presents broad concepts and their transformations: its main objective is to describe transformations, therefore it is essentially verbal. In the middle of the 20th century, two mathematicians came up with minimalistic mathematical systems which are indeed strictly verbal. The first of them is Haskell Curry’s Combinatory Logic, and the second is Alonzo Church’s Lambda Calculus. The two systems are fascinating and extremely insightful. For those interested, here’s a primer to both languages by means of colourful alligator eggs.
But there’s a less evident example of verbal languages. Visual languages as a whole (like paintings and traffic signs) tend to be adjective or nominal. One fascinating exception comes to mind: it’s impressionistic paintings. Each trace in an impressionist painting is a verb. Some of them are “upwards it oranged”, some of them are “it greened sideways, boldly”, some of them are “behind the onstreaming it happened”. No trace on its own (“it reddened downwards”) makes sense, and it takes tens of them to make a unit of sense, and thousands of them to portray the sublime aspect of a situation in detail. They might not be sentences as simple as “upward behind the onstreaming it mooned”, but they sure base themselves on the same principle.
Now, concerning adjective languages… believe it or not, but they do exist as natural languages. Not purely adjective, I’m afraid, as no language is pure. But based on an adjective paradigm, which is to say they’re nothing like anything you’ve seen. I take it as my example the only one of those languages I’m actually acquainted with: Old Tupi (or, as it refers to itself: nheʿengatu, “the good language” — literally, “good spoken”).
Old Tupi is a dead language. It was spoken by the tribespeople from the coast of Brazil by the time of the discovery. Its fundamental building block is the adjective, for instance, porang = “beautiful”. Most adjectives can be appended a nominating suffix, -a, which turns them into nouns: hence poranga = “beauty”. Some nominalised adjectives can be possessed: xe poranga = “my beauty”. Therefore, their possesed adjective forms can be taken to work as verbs: xe porang = “I’m beautiful” (more literally, “I have beauty”, or even: “my being beautiful”).
Some words cannot be posessed, like ybyrá = tree. This must be taken to mean two things: there is no adjective or posessive relation between people and trees — you cannot “have” a tree, and you cannot “be” a tree. Those words are taken to work as nouns. The rest of the language is strictly adjective made by either adjectives or modifiers, so what you have to understand is that the Old Tupi people probably thought of nouns as “funny adjectives” rather than as something else in its own right. This difference in the way of facing things leads to extreme consequences, which I invite the reader to think about.
More importantly though is that there are many classes of “pronominal modifiers”, that is to say, modifiers that include a relation between a person and an adjective in a given context. For instance, for nheʿeng = “spoken”, if xe nheʿeng = “I have speech”, then it is possible that anheʿeng = “I speak” (or, more literally, “I manifest my speech”, or even more literally: “manifestly spoken by me”). So in Old Tupi, adjectives can be adequated into verbal functions, but they’re still the building block: the adjective quality is still the basic unit of sense, which is declined into a “manifesting”, “by me” form.
In fact, this is a very important feature of Old Tupi, because it makes the language non-redundant. There is only one word for “speech”, “talk”, “conversation”, “language” etc., and it can only be possessed by one person at a time: which means I never “speak to you”, and I never “say something” in Tupi: but rather “I say”. What I said, and to whom I said it will depend on more adjectives and modifiers, but the farthest “spoken” can be bended into meaning is “I speak”.
Actually, an adjective in Old Tupi can be transitive: it can by itself posess something else. That is the case of kuab = “conscient”, “aware”. When I say xe aĭkuab i = “I know it”, I’m actually concatenating three adjectives. “It” is posessed by “knowledge” ( = “knowledge of it”) which is posessed by me: “‘knowledge of it’ of mine” = “I know it”. Headache much? Think of the possibilities.[/spoiler]
And from this you can deduce what is slightly ironic in Tlön (but perhaps it had been said in some post above). When Borges says something like: “On Tlön, all the sciences were subdued to psychology” or “On Tlön, philosophy was considered as fantastic litterature”, you can suppress “on tlön” and you get the basement of Borges’ thought. This is not so different by the way from what Nietzsche said once about philosophy, that is, philosophers first create a morale in order to justify their own behavior, then they create a philosophy in order to justify their morale, then they present the whole in the reverse order.
And that’s the reason why the end of the Tlön may look like, if not real, say possible. It just asserts that humankind is crazy (what is suggested by the reference to WWII events), that any form of craziness may be good enough for it, and that what looks crazy today will be the reason of tomorrow.
Which leads us to a very important question: have we been reading fantastic literature, or have we been reading philosophy? How are the logical grounds of science or the solid pilars of democracy any more valid than the fictions of Borges? 
That’s more like something Foucault would say. Although I agree with you that Borges himself draws a lot from Nietzsche. The whole subverting human knowledge into psychology is very cool. 
And very hard to escape, also.
Unfortunately, people still don’t know what to do with that. 
They keep saying “post modernists have dissolved the subject” and that we’re living a “crisis of sense” — not to mention Lyotard’s (“who rhymes with…”, sorry, couldn’t resist 
) name for it — but the truth is, humankind has come to a great joint realisation, namely that there are no solid grounds in the realm of knowledge, and they still don’t know what to do with it. Until people get the gist of Tlön, Uqbar, we’re cursed into living, ourselves, into real life-size instances of Tlön.
(For those interested, a list of other pretty cool stories by Borges in that sense: “On Rigor in Science”, “The Lottery in Babylon”, “The Zahir”, “The Library of Babel”, “The Book of Sand”, “Blue Tigers” (one of the most brilliant stories of all time), “The Aleph”… and my recently personal favourite: “Three Versions of Judas”).
Ok… sorry for the delay, but suggestions for May’s Reader’s Circle, anyone? I’m open to anything but I would rather have someone else recommend the book because then I know (hopefully) at least one other person will read the book, too.
Off topic: Did anyone else find what Borges said about animals ‘living in the moment’ and humans living in a string of connected moments interesting? I actually loaned the book to my pops so I can’t get the exact quote but it was in one of the last Ficciones and it really struck me as interesting and accurate in one way. But in another way I found it inept because animals do remember- when a dog is disciplined for acting a certain way, memory usually serves the animal well enough to change his/her behavior. From this perspective there is some serial order that is grasped by animals other than humans. I think that Borges really made an interesting point, though the analogy may not have been what I would consider 100% right-on. If I had a choice between the two, I often think that I would seriously consider living in one continuous moment than to live in an ever-changing sea of them, although I don’t feel as if though I ever would come to such a conclusion in the end. There is something so pure and beautiful about abandoning all logic and experience and following heart, instinct and intuition. Just another little passage I found interesting.
Well you’ll be pleased to know both you and Borges can be right. 
What happens is, the human brain has more than one mean of storing memories. Other animals have both as well, especially big mammals, but one of the two systems is extremely developed only in humans.
I don’t remember names, and can’t be bothered checking, wikipedia is your friend here, but consider the following sets of impressions and how they trigger stuff in your head: snakes, fire, your parents, a good friend, these ideas, a mathematical formula. Notice how, as you move from the former to the latter, the impressions that these ideas trigger feel less and less “primitive”? Well, the thing that I’m calling your “primitive” memory (which is the set of phenomena which strikes you at the thought of snakes, or fire, and still quite clearly when you think about your parents, but less so) is the memory backing up your instincts and conditioning.
For instance: you know what a snake is from past experience (live or otherwise), and you’ve learned to fear snakes. The very thought of a snake, unless you’re a biologist or something, is somewhat irrational and causes lots of interesting effects in your body, but also intelective in that you’re rushed to “get out”. And that is one kind of memory, which is stored somewhere at the back of your brain and is much faster than the other kind.
The “human” memory is associated with the middle of your brain, that is, the Broca Field. It’s a symbolic memory, in which memories can be arranged — for instance, but not just — along a time line. It is able of introspection, ordenation and projection: in that sense, this memory isn’t just trained for a trigger–>reaction pattern, but it can actually reason from heterogeneous past experience and conceive projections of possible future implications to current actions, balance those implications and chose for the best action. This memory, as you can see, is radically associated with intelect — although it has been observed in other animals. I’m guessing that it’s been observed in less complex forms, as so far it’s unshakable scientific belief that only very few other animals are capable of minimum language, but it’s not, by all means, an exclusively human treat.
So there you have it. Both you and Borges are right: other animals do have a perception of time, and some of them are even capable of abstracting it. But on the other hand, humans are the only known species to have a symbolic memory so complex and to base their almost every action on a linguistical projection derived from that memory. In other words: animals only experience the [i]present/i] and are conditioned for future reaction based on impressions which are always ultimately perceived as present; humans, on the other hand, are able to bring back the past through symbolic conventions, and so they’re capable to treat them as past: because they’re symbols.
Think of your parents: there’s an impression to them, that is, a very present and physical sensation of comfort and whatnot which is triggered by the notion of them. There is, on the other hand, the whole set of symbols connected to them: family, the familiar structure, their names, stereotypes you associate with their personalities, facts from the past etc. That’s the human memory. Of course I’m exaggerating a hole between the two memories which in practise doesn’t exist: they’re interchangeable and work together most of the time. But you get the idea.