The door is a symbol of secrecy and avoidance, a symbol of the quiet or sad secret struggle of the mind hiding in bliss  A house without a door is not a house, but a hallway  Wherever a man is, he can make himself at ease as long as he is behind a closed door  The mind works most effectively in a closed door
People are not horses that graze together
People need to have a way to eliminate external interference in order to improve the thinking power of the brain