Platonic Cave

"''When I made a shadow on my windowshade

They called the police and testified

But they're like the people chained up in the cave

In the allegory of the people in the cave by the Greek guy.''"

- They Might Be Giants, "No One Knows My Plan"

In Plato's famous allegory, reality is not directly perceived. We are tied down, in a cave, in front of a fire, unable to see ourselves or anyone else, only their shadows; and as we see the shadows dance and interact, we believe the shadows to be ourselves, and the walls of the cave to be the world. (And we would find it difficult to see if brought into greater light.)

A Platonic Cave setting is one in which the cave is shown to be artificial. Stories in this setting frequently have to do with peeling back layers, trying to get closer to reality. Not the cave you only like.

A Cuckoo Nest plot uses this as part of a single episode's story.

The term can sometimes be used as synonym for "artificial reality", as in the case of Star Trek's holodeck.

Compare Cyberspace. May overlap with Lotus Eater Machine.

Beware of spoilers beyond this point.

Anime and Manga

 * In Digimon Adventure, the "cave" is a cave. Matt, Sora and arguably Kari and Ken (Dark Ocean) all get stuck in the same cave that only exists because of their insecurity and sadness.
 * The Big O. Maybe. Possibly. Could be.
 * Referenced in the lyrics for Aura's song in .hack//Sign.

Comic Books

 * The Invisibles, where our universe is the intersection between two others. When someone is taken to The Invisible College, they are told "Imagine the world is the pattern on the wallpaper...well, now we're in the wall."

Film

 * The Matrix, of The Matrix. The "cave" is a giant computer program.
 * The Truman Show. The "cave" is a town-sized TV show soundstage.
 * The ending of the movie Brazil. The "cave" is the main character's own mind after going insane under torture.
 * Partial example: They Live!, in which radio signals are beamed into our brains, causing us to see things inaccurately.
 * Dark City - The cave is an alien spaceship/laboratory made up to look like an American city ca. the 1930s.
 * The 13th Floor - The cave is a virtual reality simulation inside of another virtual reality simulation.
 * eXistenZ - The cave is the virtual reality game. However, Plato's theory is subverted when it turns out that . And the people who want to destroy the cave? Insane terrorists who want to stop you from playing video games.
 * THX 1138: The cave is the entire underground city, and the final scene is a clear reference to the "rough ascent" and transcendence as described in the allegory.
 * El Topo takes a very literal interpretation of this trope. Psychedelically.

Literature

 * Robert Heinlein's short story "They" has the protagonist catching on to the fact he's in a cave when someone running the world messes up and it's raining outside one window and sunny outside another. They send in a psychologist to try to convince him that he's schizophrenic.
 * Used in Shelley's Frankenstein in the Creature's narrative.
 * The protagonist of William Gibson's book Neuromancer is at one point inside a virtual reality program, sitting by a bonfire, inside something very reminiscent of a cave.
 * In The Great God Pan, the scientist responsible for the whole plot did the experiment because he believed in this theory, and wanted to expose part of the "real" reality to ours. Whereas this is true or not is not specified, but given the fact that an Eldritch Abomination is running around it is likely so.
 * In Isaac Asimov's I, Robot, the story "Reason" revolves around a robot who becomes convinced that the space station on which he works is his entire universe, and the duties he performs on the station are rites for a deity.
 * In the Horus Heresy novel A Thousand Sons, Thousand Sons primarch Magnus the Red retells the story in an effort to convince the Emperor that he should allow continued exploration into sorcery.
 * Heaven by Ian Stewart and Jack Cohen happens mostly in the real world, but it involves Lotus Eater Machine "worlds", and contains one scene like this. An initiate to the deeper secrets of the religion setting up these fantasy worlds is shown inside one like them and then returned to the office where he was. His instructor argues that the virtual reality he experienced was real, and he disagrees. He says that what is really real is this, meaning his surroundings, at which point he's awoken and realizes that was actually another simulation, used just in order to make a point when he'd start going on about it being more real than the first one.

Live-Action TV

 * The setting of Life On Mars... maybe.
 * The Shibuya in Sh15uya is explicitly stated to be a virtual replication in the opening of the show.
 * The Doctor Who two-parter "Silence in the Library"/"Forest of the Dead". The "cave" is.
 * The Matrix in "The Deadly Assassin", in "Castrovalva", and the alternate realities in "The Celestial Toymaker" and "The Mind Robber". Also   in "The Android Invasion".
 * Also the tunnel in Gridlock.
 * Star Trek: The Next Generation: Professor Moriarty discovers that he's a character in a holodeck fantasy, and it even gets down to the point where he is questioning the memories and personality he was programmed with, rejecting them for a chance at a new identity and existence. When Picard fails to live up to his promise, a follow up episode has Moriarty trapping Picard and Data in one of these briefly leading Picard to muse that their own reality might be a Platonic Cave.
 * Star Trek: Voyager has the Q create a representational reality that reflects the basic ideas of the Q Continuum for us mere mortals (though they don't try to fool the humans into thinking it's real, it at least suggests that there is more to reality than they're capable of handling.)

Tabletop Games

 * Mage: The Awakening. Reality itself is the "cave," a "fallen" portrayal of the limitless wonder of the Supernal Realms. And even for those who manage to break the ropes and turn around to look at the way out, there are demiurges guarding the mouth of the cave, and a trench before you can even get to them.

Video Games

 * Star Ocean: Till the End of Time reveals that the entire universe is a simulated reality and, consequentially, everyone in it is an AI program.
 * Final Fantasy Tactics Advance - The cave is the world created by the magical book.

Web Comics

 * This strip from the Web Comic Arthur, King of Time and Space has Plato actually doing this.
 * This strip from Daisy Owl has a fly trapped in one.
 * Tailsteak's comic The Sixth TV is an unusual take on the cave, and indeed begins with a quote from Plato.

Real Life

 * Several physicists have suggested ontologies that Plato would have been proud of:
 * Cosmologist Paul Davies, along with a good number of other scientists, philosophers and theologians, believes that the universe is nothing more than a very powerful quantum-digital computer. He even proposed an experiment that could be performed pending developments in computer engineering.
 * Max Tegmark thinks that only math exists, and that what we perceive as real, is nothing more than equations tricking themselves into thinking that they exist in a real world.
 * And probably weirdest of all, after considering the philosophical consequences of the violation of Bell's Theorem, Bernard d 'Espagnat concluded that the Laws of Physics are nothing more than the shadows of a panentheistic god.
 * Pythagoras believed that numbers were the true nature of everything. This became an empirical theory by Issac Newton, who would codify how to use mathematics to describe physics.
 * In a very real sense, we don't perceive anything but shadows. You think you see other people, but that's just light hitting your retina. What you hear is just ripples in the air. What you feel is just pressure picked up by your nerves. Humans do not have one single sense that directly perceives how we interpret the data we receive from the environment.
 * Also the fact that we're all living slightly in the past. All signals take some time, an incredibly small amount of time, but still, for the brain to interpret after they're recieved.
 * The Balinese believe something very similar to this. Everything we see and experience is a reflection of the real world. The sacred theater of Bali includes wayang (reflection) plays using flat puppets made of leather behind a lit sceen, so all you see is their shadows.
 * Some Indian peoples believe this also. To get into the real world, you have to dream. Crazy Horse was one of many holy men known for the ability to be in both worlds at once.