Plato's Cave is a famous philosophical construct wherein hypothetical prisoners are tied down facing one wall of a cave so they can't move their heads and look around. Behind them is a fire providing light for the cave, and between the fire and the prisoners are puppeteers moving back and forth holding various objects that cast shadows on the wall for the prisoners to observe. It's a hideously contrived scenario, but Plato used it to demonstrate the difficulty of expressing concepts through language when we don't have a concrete experience with those concepts. A prisoner might say "I see a book" based on a projection, but there's no book on the wall only shadow. It's only when they're released and can look around that they can see the real objects casting shadows. True understanding, Plato argues, isn't possible until then.
What I find curious is how many Christians love to inject Jesus into Plato's Cave. Plato wrote passionately about mistaking an image for the real thing, then Christians try to tie their invisible, intangible god as the fire lighting the wall. The mind boggles.
There are lots of ways to examine this religious hubris, but I found my thoughts moving in the direction of Schrödinger's cat. Like Plato's Cave it's a thought experiment, not meant to be taken literally. He made it to argue against the Copenhagen Interpretation of quantum superposition, but like the Christian version of Plato's Cave I would like to borrow it to make a point.
Schrödinger supposed that if you took a solid metal box, a cat, poison, a geiger counter, a hammer and a tiny amount of radioactive material you could construct a situation where the geiger counter is set to possibly detect the radioactive material, but it's not reliable because there's so little radioactivity. If it does, the geiger goes off which releases the hammer to smash the vial of poison. The poison kills the cat, whose only crime was to be imprisoned in the stupid box by silly humans. Does the geiger counter go off and doom the cat, or does the geiger counter miss the radiation and let the cat live? Under the Copenhagen Interpretation, Schrödinger argued, the cat is both alive and dead until the box is opened and the quantum superposition is observed.
Where am I going with this? Both Plato's Cave and Schrödinger's Cat address knowledge. We can't know things until we observe them, we can only speculate. Speculation is not knowledge. The best guess in the world is still just a guess until the answer is revealed. It's important to remember not to declare victory until we actually achieve victory conditions.
Remember Jesus in Plato's Cave? 
The Christians who borrow this allegory are doing violence to Plato's philosophy. In their cave all shadows are imperfect reflections of their god, which is why everybody has a different idea of what they're looking at. Plato himself asked why the prisoners wouldn't discuss the images between themselves and work out agreement on what they were supposed to be looking at, which is something we've been doing about gods for thousands of years. Of course, we're no closer to an answer today than we were ten thousand years ago. Christians agree that we're all prisoners in the cave, but they're the ones who actually know what those shadows represent! How? Because they feel it. Because they fake it until they believe. Because the Bible says so. Because...they just know, okay? Because shut up, that's why!
I'm constantly confronted with claims of knowledge in my daily life. Living in the age of information makes it a challenge to parse all those claims to separate the ones that are true from the ones that are false. Until I do, each one remains in a quantum superposition of being both true and false until it can be unpacked and examined. The shadows on the wall don't represent knowledge, they represent what we think is knowledge until our assumptions can be tested against the real thing. Always remains skeptical of people who are confident of the truth without being able to demonstrate how they know it. In the end, if you know you're right but can't explain it you should reconsider the possibility that you're actually wrong.
