This consciousness, which has become the brain, which has become the inner faculties or organs, is of immense power. One thought came in the mind to make a television and that thought manifested as television. All possible advancement in any field today, either science or arts, you see, originated as a thought, originated in that ocean of intelligence.
People talk about science meeting spirituality or spirituality coming together with science. This is such an immature, childish statement. Spiritual knowledge is science, and science can never be away from spiritual knowledge because spirit alone can bring the science out. These are two sides of the same coin; even to say this is not so appropriate. It is one and the same. One consciousness through the senses perceives, goes out and perceives, experiences. That is mind.
The same consciousness, whatever it has perceived, retains the impressions. That is Chitta (subconscious mind). And the same consciousness there sits and judges, “Oh, I want this, I don’t want this. I like this, I don’t like this.” That is Buddhi, the intellect. And the same consciousness says, “I, I, I, me, me.” That is ego.
When you sleep, your ego is dissolved, your mind is at rest, your intellect is at rest. Only Chitta is functioning. That is when the dreams simply hover around, some memories just hover around, come and go. Dream is just the function of Chitta, the remaining three are resting. Ego is at rest. In deep sleep, even Chitta is at rest, ego is totally at rest. In the waking state, all the four are functioning more or less.
An excerpt from Sri Sri Ravi Shankar's talk on Yogasara Upanishad