Plato's Allegory of the Cave—you know, the one where we're all tied up in an underground cavern watching reflections of a counterfeit reality instead of up on the surface experiencing absolute truth—is one of the most important concepts in the history of philosophy, and it's arguably the basis of all Western mysticism. It's also a popular theme in SF—particularly filmic SF, for some reason. Here are just a few examples:
You probably knew that Pixar's latest was a combination of post-apocalyptic SF and cute, attractively-designed robots. But by the time the eponymous trash-compacting 'bot gets to space, it becomes a riff on Plato's cave. When the growing tide of Earth's garbage grew too great, humankind abandoned the planet, departing on the space ship Axiom while robots cleaned up the surface. 700 years later, human culture has atrophied—the inhabitants of the Axiom spend their entire lives strapped into hoverchairs, conversing with their fellow exiles on floating computer screens that fill their entire field of vision. They've completely forgotten what it means to be human—until Wall-E, in the role of Plato's philosopher, shows up to deliver some much-needed anamnesis. Before long the Axiom's human inhabitants are stargazing, walking on their own feet, and ready to reclaim the Earth. On one level it's a particularly clever SF critique of consumerism; on another, an interplanetary transplant of Plato's most famous concept.
Doctor Who: "Gridlock"
The third-season Doctor Who episode "Gridlock" depicted a particularly unpleasant dystopia: a traffic jam the size of a planet where travelers live entire lives in their cars, searching for exit ramps that never appear. In one of his more messianic actions, the Doctor sets the eternal commuters free, and the image of their cars rising towards the light of the surface is a clear reference to Plato's sunlight of truth. (For more on this episode, read my full review here.)
The Island doesn't get much respect, but it's probably the best movie Michael Bay will ever make. The Island, an uncredited remake of '70s clunker Parts: The Clonus Horror, opens in an underground complex whose bubbleheaded inhabitants live in simplistic harmony. When one of them escapes, he learns the awful truth: they're all clones being raised for parts; when their originals need an organ, they'll be harvested. Many, many chase scenes follow, but the highlight of the movie is a confrontation between the lead clone and the person he's cloned from—the false object seeks out its own ideal form, and finds it wanting.
This 21st-century reboot of Plato's allegory is very likely screened in more introductory philosophy classes than any other film. Here the shadows on the cave wall are a full-fledged virtual reality. But, in a fairly clever twist, those who escape into reality end up... in a cave. Plot necessity, or cynical comment on the quest for spiritual experience? In many respects The Matrix gets a bit more credit for its philosophy than it deserves—Buddhism is famously reduced to a platitude about spoons—but Plato's Cave is one thing it gets very, very right.
The inhabitants of a dome city of the future must commit ritualized suicide on their thirtieth birthdays. Logan, a "sandman" who enforces this order, starts to wonder why—and, when he leads his people out of the prison of their world at the story's end, it's a nice illustration of a society casting off its bonds and embracing a new vision of reality.
In SF, it seems that the domed city replaces the cave. When the dehumanized hero of George Lucas's first feature escapes his narcotized society, we're treated to a lengthy shot of him standing in silhouette before the sunrise—dazzled, like Plato's philosopher, by the blinding light of the truth.
It could be argued that Philip K. Dick's entire oeuvre illustrates Plato's allegory, but Ubik probably does it best. When a team of psionic spies is injured by a bomb, they're trapped in cryogenic "half-life," experiencing a world they think is real. Their first clue that something is amiss comes in a particular Platonic form as objects regress into older versions of themselves—a supersonic jet becomes a biplane; a holographic display becomes a TV, then a radio. In this case the ideals are less than ideal, but that doesn't stop Ubik from being one of Dick's most philosophically rewarding novels.
1984 by George Orwell
If you've been wondering why so many of the above stories are dystopias, this is why. There's a Platonic edge to all dystopian fiction, and Orwell's definitive world-gone-wrong gives the clearest example of why. Humanity languishes in chains while evil forces subject shape their experience of reality by manipulating the truth—it's a dark vision of Plato's concept, but certainly a striking one.
For more on Plato's cave and religions experience in SF, see chapter 7 of The Gospel According to Science Fiction.