The document discusses how vision perceives objects as both near and far even when their physical distances are fixed. It uses the example of watching a movie, where the camera and screen are fixed but viewers still perceive some scenes as closer and others farther away. This is because the mind contains an "impurity" that makes it perceive differences in distance mentally rather than physically. Through meditation and reducing this mental impurity, one can see the world without such perceptions of near and far and instead view everything on the same plane.