THERE IS NO PROOF OF THE EXISTENCE OF THE ABSOLUTE OTHER THAN YOUR OWN EXPERIENCE.
Robert used to say, "Be aware of the arising of the I when you awaken." It comes from nothingness and returns to nothingness each day.
If you can just stay in that twilight state when you first awaken, stabilize there, and then go back and forth between sleep and waking, you will experience that there is "something" that is aware of the comings and goings of Consciousness. It is not really a thing, but a "behind" state from which all other states of Consciousness arise. Every morning your Consciousness is born out of nothingness.
Meditators also go through this state of the disappearance of Consciousness and its reappearance, and thereby become aware that they ultimately are the witness of its coming and going. Then yu can learn how to rest in the Witness state even while you experience body and mind, but there will be no words or thoughts there, only the deepest and most incredible peace.