Why darkness exists in society

The depressing term of darkness is able to make a name for itself, survive, and thrive in a society based upon good morals and good intentions. Why? It is the same principle as black on white. You will never know the how pure and simple white is until you see the hideous looming black behind it, creating that contrast, that attention the black craves for. Therefore, darkness is able to exist in our society due to the need of a contrast to the good morals and good intentions. Without the darkness looming behind, the good morals and actions will never be noticed and will never shine through the dark. Remember, a hero would not exist is there was a villain. The two need each other to survive, to thrive in the monster of society that will reel you in and spit you out. Their nature are forever entwined and their paths inseparable.