Shankara was an 8th century Indian saint and philosopher who is regarded as the founder of the Advaita Vedanta branch of Hinduism. He wrote the following about the Witness.
Now I shall tell you the nature of this absolute Witness. If you recognize it, you will be freed from the bonds of ignorance, and attain liberation.
There is a self-existent Reality, which is the basis of your consciousness of ego. That Reality is the witness of states of ego consciousness and of the body. That Reality is the constant Witness in all three states of consciousness – waking, dreaming, and dreamless sleep. It is your real Self. That Reality pervades the universe. It alone shines. The universe shines with Its reflected light.
Its essence is timeless awareness. It knows all things, Witnesses all things, from the ego to the body. It is the Witness of pleasure and pain and the sense-objects. This is your real Self, the Supreme Being, the Ancient. It never ceases to experience infinite release. It is unwavering. It is Spirit itself.
If we are aware of this screen, we are already completely 100 % saturated with this infinite consciousness. However as the great masters tell us, what good does this do us if we’re not aware of the infinite release of this realization? When we deeply ask the question ‘What or who am I, what is this infinite consciousness?’, we are allowing ourselves to become what Zen master Hakuin called The Great Doubt: “At the bottom of great doubt lies great awakening. If you doubt fully, you will awaken fully.” The Zen masters teach us that the fully awakened mind is always already fully present in its entirety, with nothing lacking.
When I first started practicing Zen, this statement became the object of my own great doubt. My questioning brought me face to face again and again with the reality that my thinking mind did not, could not, fully believe this statement. Gradually it became clear that there was no way to do away with the doubt. Great doubt is one expression of what we are. It became clear to me that to deeply ask the question of “Who am I?” was to allow myself to become the doubt itself. If there is self realization, it can’t be separate from the doubt itself.
Eventually I realized I had thought all along that I was doubting Buddha nature, doubting enlightenment itself. But when I finally left my awareness to itself, including all my ideas about it, I realized what is actually here and now cannot be doubted. For the awareness we are is doing the doubting! All this time, I had been doubting the truth of my ideas of reality. There is no truth to be found in the concept of enlightenment or Buddha Nature. So it is imperative to doubt the truth of our concepts about enlightenment, and at the same time to be aware what we are doubting.
Reality is not an it that can be doubted or affirmed. Reality cannot be grasped by making it into an object of thought. But we have to try. Indeed, our spirit of inquiry is deepened by our trying. It is deepened by our wanting to know. This is our role: not to know what reality is. Here and now is the source. Here and now is one hundred percent identical with every possible manifestation in the universe. If we doubt this idea deeply, we will awaken deeply.
There is a saying in Zen: with little doubt, there is little realization. With no doubt, there is no realization. With great doubt, there is great realization. What is great about great doubt is its all inclusiveness. It is the driving force of our spirit of inquiry leaving no rock unturned, no blade of grass not looked behind. We really have to look at whatever knowledge we’ve accumulated, whatever great realizations we imagine to have attained, and doubt them all deeply, being willing to totally throw them away. The greatest realization is just a shadow of dust reflected by spirit itself; it’s all conceptual, thought energy dissolving in the wind.
There is and an old Zen story about Bodhidharma, the great Zen master who brought Chan (now Zen) Buddhism from India to China. His spirit of inquiry is legendary in the history of Zen, and he is said to have sat in front of a wall for nine years arduously and deeply immersing his whole being in the heart of the Buddha’s teaching about the true nature of self, and liberation from human suffering.
One of his closest disciples, named Jinko, intimately shared Bodhidharma’s deep yearning for truth. Life was very difficult in those days, even for monks who renounced the world. One day in a state of extreme desperation, Jinko came before his master and said “My mind is deeply agitated, please pacify it for me!” The story says he was so desperate that he had (or perhaps was ready to?) cut off his arm to show to Bodhidharma. Bodhidharma replied, “Show me this mind of yours, and I will pacify it for you.”
So Jinko returned to his room, and searched for his mind with all his heart. He really stretched his limits of will power, deeply contemplating the question of how much can I or anybody want to find the actual essence of what we are, what life actually is? He even spent all of several nights standing outside Bodhidharma’s room in the falling snow. Finally when he was completely exhausted, he returned to Bodhidharma and confessed, “Master, I have searched with all my heart and soul, but I cannot find my mind.” Bodhidharma said, “Then I have already put it to rest for you.”
We can’t manufacture great doubt like Jinko’s. But it is there in all of us waiting to be uncovered and surrendered to. Then it’s transformed from negating everything to affirming everything as the light of divine spirit. Our spirit of inquiry, our doubt, and our faith and devotion come together to show us what we really are.