But philosophically, "idealism" is a whole nother cat and a whole nother canary. Borges mentions that the formal hypotheses of idealism, like those of George Berkeley's, are functionally unfalsifiable. ("Hume noted for all time that Berkeley's arguments did not admit the slightest refutation nor did they cause the slightest conviction.") Here, you have the opportunity to introduce both a fundamental alternative to empiricism to your students! And, maybe more importantly, why and how our models of science, of the philosophy of knowledge, fall short of determining its veracity. What other kinds of notions are unfalsifiable in the same way? What makes such a notion valuable despite this lack, or dismissable because of it? Absent anything else, Tlön, Uqbar, Orbis Tertius does function standalone vessel or vehicle for introducing the philosophy of idealism without needing the nuance of each different version espoused by different continental scholars over different centuries. Consider the parable of the copper coins:
On Tuesday, X crosses a deserted road and loses nine copper coins. On Thursday, Y finds in the road four coins, somewhat rusted by Wednesday's rain. On Friday, Z discovers three coins in the road. On Friday morning, X finds two coins in the corridor of his house.
Which on its face seems obviously plain to us (nine coins are lost, they persist in existing while they are lost, and in time each of the always-existing nine coins are found), and obviously wrong to them, where there is no reason at all to suggest a fixed unseen continuity connects the beginning to the end.
They explained that equality is one thing and identity another, and formulated a kind of reductio ad absurdum: the hypothetical case of nine men who on nine successive nights suffer a severe pain. Would it not be ridiculous—they questioned—to pretend that this pain is one and the same? They said that the heresiarch was prompted only by the blasphemous intention of attributing the divine category of being to some simple coins and that at times he negated plurality and at other times did not. They argued: if equality implies identity, one would also have to admit that the nine coins are one.
The key is to unhook everything you know about your methods of determining the phenomena around you, and replace the sensory simulacrum of reality you think you perceive with your perceptions themselves. They are the real thing. For a moment, suspended in this way, maybe after a second or third reading and resolving a few elementary questions in classroom discussion, they will see their very act of sight, their thought of thoughts, as the walls of the cave. I consider this disjoint with the rest of the students' lives, that burst of terrible clarity, to be entirely safe because it is not true. The disqualification of the idealist hypothesis is not a logical one that depends on enumeration; you do not need to nurse someone back to our side of the fence. It is the product of cultivation which is the benefit of culture and civilization. This is why the citizens of Tlön believe the way they do, as well, and perceive the common world in alien ways; it is inculcated through the massing power of culture.But not everyone will make it under that ocean's surface, and in the long tail, one or two will find themselves struggling to come back up for air. This is not an ethical compromise: the former will live their lives without being upset about the sanctity of their continuum; for the latter, this experiment will still be helpful in finding that their oxygen supply was always already being limited by ideas similarly incongruous with our approximated amalgam of shared empirical reality.
I relate to you that there are two problems, on either end of a spectrum, that can lead philosophical individuals to be out of step with their fellow man. The first, and more loudly common, is the nihilist or solipsist: the difficulty in seeing other people as truly People. The second, however, is the projection of an idealist heart: the difficulty in seeing other people as truly Other. To these philosophers, and to those of Borges' Tlön, one man is all men.