This post is a part of my study of philosophy for understanding catholic theology
So there's this cave...
The start of it all is a thought experiment Plato (4th-century BCE) presents to explain reality. He suggests that reality is as if...
Imagine that there are some people in a cave underground. They are chained in such a way that they cannot move or see anything except the far side of the cave, on which they see only shadows. The shadows are cast by objects that are held up behind the people, and behind that is a source of light, a big fire. The people have always been there, forever and ever, amen. From their perspective, the shadows are the only things that exist at all - they think the shadows are reality. What they don't know is that the shadows are shadows of real things (really real) and so they don't understand that reality is in fact much richer than they have any idea of. The real objects have colour, depth, texture, weight, and a whole bunch of other exciting things not standard equipment on shadows. But the shadows themselves are entertaining enough - for most of the people, life is good where they are, and knowledge of the shadows is quite enough to congratulate themselves on.
But, says Plato, there's a plot twist. Imagine that one person breaks free of the chains, manages to turn around and - gasp! - see the real objects for what they are. How magnificent! That person's reality has exploded, mind blown, bangs crimped. Lookit that! What's that strange thing! I think I'll call it 'blue'! And that there, I'll call that 'curly'... and so on. That person can't just go back to shadows, but is transfixed by the really real objects about which he had only known shadows. So he keeps looking, and finds the light behind the objects that's casting the shadow - ouch! Too bright, but after a time he can bear to see things in that light.
Hey, wait! There's more to my universe than chains, so I'm going to walk around. Eventually, that person climbs his way out of the cave, or down the rabbit hole, or takes the red pill, whatevs. Wow, I mean really wow! Outside the cave! There's shadows, like before, and objects, like I've recently become accustomed to, but there's something absolutely astounding: up! And in this up, there is a roughly circular disc of brilliant light, way brighter than the underground fire. Again, ouch!
But eventually this person's eyes adjust and he explores this brave new world with aplomb and happiness. Not the end. For Plato has an idea of social dynamics, so this enters his fabled thought-experiment. Eventually our liberated, future-so-bright, former-cave-dweller remembers his former empty life and realizes all his buddies back underground are missing out. He's such a nice guy that he has to go back and tell them what they're missing and bring them out into the light so that they can have knowledge of the true reality that he's experienced. (I might be ironic, here, I'm not sure yet...)
So down he goes, back into his prison out of love for his fellow men. He approaches his buddies and says, "Everything you know is wrong! Follow me to a deeper and more satisfying truth." And they beat the crap out of him. Because they are so infatuated with the shadows, they resist anyone who might jostle with their comfortable illusion. So the tortured lone voice of truth is persecuted, the ignorant masses get violent, and the shadows remain enticing.
Plato makes the case with his thought experiment that the reality we perceive with our senses, including sight, hearing, taste and the like, and perhaps even things we perceive with our minds, like justice, friendship and attraction, are all 'shadows' of what he calls 'forms' - the true reality of things. Every horse we see or ride is a 'shadow' of the form of 'horse' - and if we had eyes to see the really real, it would be dramatically more exciting and fulfilling and true and good. What's more, there's a theology in this, in that he believes that the 'light' which casts the shadows we call reality is in fact God, the originator of the world. So by unchaining ourselves, we have the capacity to see everything in this divine light.