One afternoon a blind man was sitting next to his friend talking in a plaza, after several hours of conversation he realized that it was time to go home, when his friend's blind man said goodbye, he gave him a lamp as he was darkening. The blind man in a mocking but respectful way told his companion: "I do not need the lamp, because for me, clarity or darkness have no difference," said the blind man. And his companion nodded to him, "It's true, but if you do not take it, maybe other people will trip on you.