There used to come to Naren's house many of his father's clients. They would sit together chatting until their turn for consultation came. They were of various castes; there was even a Mohammedan, with whom Naren was particularly friendly, and each was provided with his own hookah. Caste was a mystery to the boy. Why should not a member of one caste eat with a member of another or smoke his hookah? What would happen if one did? Would the roof fall in on him? Would he suddenly die? He decided to see for himself. Boldly he went round the hookahs and took a whiff from each and every one. No, he was not dead! Just then his father entered. "What are you doing, my boy?" he questioned. "Oh, father! why, I was trying to see what would happen if I broke caste! Nothing has happened!" The father laughed heartily and with a knowing look on his face walked into his private study.
Even at an early age Naren evinced impatience with superstition and fear, no matter how hallowed by popular tradition. As he himself expressed it to a disciple in later years, "From my boyhood I have been a dare-devil; otherwise could I have attempted to make a tour round the world, almost without a penny in my pocket?" An incident that occurred around this time is illustrative of his "dare-devilry", which is to say, courage and independence of thought and action. To the house of a certain friend he would often have recourse as to a refuge from the monotonous moments that come even to boys. There was in their compound a favourite tree from which he loved to dangle head down. It was a Champaka (Michelia Champaca) tree, the flowers of which are said to be liked by Shiva, and which Hindu boys would go a long way to collect. It was the flowers of this tree that Naren also loved. One day as he was swinging from the tree, the old and nearly-blind grandfather of the house recognized his voice, which he knew and loved so well. The old man was afraid that the boy might fall, and that he himself might lose his Champaka flowers; he called Naren down and told him that he must not climb the tree again. Naren asked the reason. The old man answered, "Because a Brahmadaitya [a ghost of a Brahmin] lives in that tree, and at night he goes about dressed all in white, and he is terrible to look at." This was news to Naren, who wanted to know what else this ghost could do besides wander about. The old man rejoined, "And he breaks the necks of those who climb the tree."
Naren said nothing, and the old man went away smiling to himself in triumph. As soon as he had gone some distance Naren climbed the tree again just to spite the ghost of the Brahmin. His friend remonstrated, "The Brahmadaitya is sure to catch you and break your neck." Naren laughed heartily, and said, "What a silly fellow you are! Don't believe everything just because someone tells you! Why, my neck would have beenbroken long ago, if the old grandfather's story were true."
Only a boyish lark it was, true, but significant when viewed in the light of later developments: a forecast of the time when, as Swami Vivekananda, he was to say to large audiences, "Do not believe a thing because you read it in a book! Do not believe a thing because another has said it is so! Find out the truth for yourself! That is realization!"