In his work "Republic", Plato, the ancient philosopher, describes a group of individuals who have been chained inside a cave, since their childhood. Their necks and legs immovable, forced to constantly stare at the cave's wall in front of them.
Behind, another wall, lower, manmade, where people cast shadows of objects moving in front of a fire, in the fashion of a muppet show, to the prisoners.
These shadows are all they can see.
Although not a faithful depiction of world, the shadows became the captive's reality. No colors, no depth, no textures. Only the limited dark shapes moving and dancing along the wall.
Much like you right now.
Difference is: Your brain has seen the world and see...