Ponder this, my friends. If you were born inside of a box with a thought of a world outside it, a world that is more real, ever enter your mind? Considered one of philosophy's greatest writers, Plato asked just this sort of question in his famous allegory of The Cave. Imagine, a group of people born into a cave, chained by their legs and necks, facing the back wall. The only thing they can see are shadows cast by a fire behind them, and since they've never seen the actual objects, they think the shadows are real.
But what would happen if one of the prisoners were to be set free? When he turns round and sees the objects, will he know that the shadows are a lesser copy of reality? And when he eventually leaves the cave and sees the sun and nature for the first time, would his mind not be completely blown?
But wait a sec, if the objects are more real than the shadows, how do we know there isn't something more real than the objects? The ultimate reality is what Plato calls the Realm of the Forms. It is eternal, unchangeable, it is the realm of being, of what is. Our world on the other hand is the world of becoming, of change and what we perceive, where everything is constantly becoming something else.
Just as the shadow of an object is a faded copy of the actual object, the world as we perceive it consists of imperfect copies of the forms. After experiencing the higher truth, what would happen if the prisoner returned to the cave? Plato muses that telling the others of the greater reality would threaten their narrow beliefs. If they could, they might even kill him.
Will we as humans ever be able to lose our shackles of perception and truly know reality?
Summary: The philosopher Plato described life with the allegory of The Cave. In it, all humans live inside a cave and watch shadows on a wall which are formed by objects flickering in front of a fire behind them. Their idea of reality is only shadows of the real thing. To understand ultimate truth would be to somehow exit the cave and see the sun and nature, true reality. Plato argues further though that even this wouldn't be reality, for there is a higher reality of the forms which our reality only imitates. In our world, things are constantly changing and becoming whereas in the world of forms, things are already perfect and complete.