A beautiful anecdote about the Adi Shankaracharya, the first shankaracharya from a Master.
Shankaracharya was in Varanasi. One day, early in the morning -- it was still dark because traditionally the Hindu monks take a bath before sunrise -- he took a bath.
And as he was coming up the steps, a man touched him on purpose, not accidentally, and told him, "Please forgive me. I am a sudra, I am untouchable. I am sorry, but you will have to take another bath to clean yourself."
Shankaracharya was very angry. He said, "It was not accidental, the way you did that; you did it on purpose. You should be punished in hell."
The man said, "When all is illusory, it seems only hell remains real." That took Shankaracharya aback.
The man said, "Before you go for your bath, you have to answer my few questions. If you don't answer me, each time you come up after your bath, I will touch you."
It was lonely and nobody else was there, so Shankaracharya said, "You seem to be a very strange person. What are your questions?"
He said, "My first question is: Is my body illusory? Is your body illusory? And if two illusions touch each other, what is the problem? Why are you going to take another bath? You are not practicing what you are preaching. How, in an illusory world, can there be a distinction between the untouchable and the brahmin? -- the pure and the impure? -- when both are illusory, when both are made of the same stuff as dreams are made of? What is the fuss?"
Shankaracharya, who had been conquering great philosophers, could not answer this simple man because any answer was going to be against his philosophy. If he says they are illusory, then there is no point in being angry about it. If he says they are real, then at least he accepts the reality of bodies... but then there is a problem. If human bodies are real, then animal bodies, the bodies of the trees, the bodies of the planets, the stars... then everything is real.
And the man said, "I know you cannot answer this -- it will finish your whole philosophy. I'll ask you another question: I am a sudra, untouchable, impure, but where is my impurity -- in my body or in my soul? I have heard you declaring that the soul is absolutely and forever pure, and there is no way to make it impure; so how can there be a distinction between souls? Both are pure, absolutely pure, and there are no degrees of impurity -- that somebody is more pure and somebody is less pure.
So perhaps it is my soul that has made you impure and you have to take another bath?"
That was even more difficult. But he had never been in such trouble -- actual, practical, in a way scientific. Rather than arguing about words, the sudra had created a situation in which the great Adi Shankaracharya accepted his defeat.
And the sudra said, "Then don't go take another bath. Anyway there is no river, no me, no you; all is a dream. Just go in the temple -- that too is a dream -- and pray to God. He too is a dream, because he is a projection of a mind which is illusory, and an illusory mind cannot project anything real.