The Chandogya Upanishad tells as story about Svetaketu, a young man of ancient India who, on returning to his home after twelve years of studying the Vedas, appeared to his father to be as somewhat set up about his vast learning. The father therefore set out to teach him some homely but profound wisdom not necessarily learned from books.
“Bring me,” he said to his son, “a fruit from a banyan tree.”
“Here is one, sir.”
“Break it.”
“It is broken, sir.”
“What do you see there?”
“Some seeds, sir, exceedingly small.”
“Break one of these.”
“It is broken, sir.”
“What do you see there?”
“Nothing at all.”
The father said, “My son, that subtle essence which you do not perceive there – in that very essence stands the being of the great banyan tree. In that which is the subtle essence all that exists has its self. That is the true, that is the Self, and you, Svetakeu, are that.”
“Pray, sir,” said the son. “Tell me more.”
For the second lesson the father gave his son a bag of salt, saying, “Place this salt in a vessel of water and come to me tomorrow morning with the vessel.”
When the son appeared the next day the father commanded, “Bring me the salt which you put in the water.”
But the salt of course had disappeared.
“Taste the water from the surface of the vessel and tell me how it is.”
“Salty,” said the son.
“And from the middle?”
“Salty.”
“And from the bottom?”
“Salty also.”
Then the father said, “Here likewise in this body of yours, my son, you do not perceive the true, but there in fact it is. In that which is the subtle essence, all that exists has its self. That is the true, that is the Self; and you, Svetaketu, are that.”
-Changdogya Upanishad