Sri Sri Ravi Shankar:
Lord Buddha said, “I went in meditation, I searched and searched and searched for the soul, I could not find it. So there is no soul, there is no atma.” That become anatmavad. He said everything is hollow and empty. There is no soul, there is no person, no entity. It is all nothing, everything is nothing. This is what Lord Buddha propounded.
Then, after sometime Sri Adishankara came. He said Ok, is that case! You didn’t find anybody. Right? But who experienced that nothingness. Who experienced that there is no self? Who searched and found that there is no self?
Someone must have searched; someone said there is no self. That is the self. That is how using the same logic of Buddha, Sri Adishankara brought back the Vedic wisdom back into India.
And the places he travelled, today is India. From Kerela to Kashmir, from Gujrat to Orissa to Kamagya. He travelled to these areas and that became India. The Self is like the space. It is not an entity or an object. In fact, what lord Buddha said and what Adishankara said there is not much difference, only one change, a flip in thinking - Buddha says it is all nothing, Adishankara says it is all fullness, everything is full, every single inch of space is filled with knowledge and information.
He says this entire universe is consciousness and consciousness is true infinity, wisdom and information. That is why great scientists like Albert Einstein appreciated this so much. They said the Bhagwad Geeta, the Upanishads are the greatest scriptures, reading which their whole life changed. What the scientists are saying today about the black hole, dark matter, dark energy, has been said long time back.
If you listen to a quantum physics scientist and listen to Vedanta, you will feel that they are talking the same thing.