The root of all inquiry is the question "Who am I?" Under persistent questioning, the mind will not be able to locate itself, its own sense of "I"-ness. When the mind sees for itself that it canÕt locate anywhere who it pretends to be, the habitual patterns of perception associated with our particular "I"-ness disappear in a flash of intuitive awareness.
When Zen master Tokusan had this insight, he threw his treasured copy of the Diamond Sutra, the sacred Buddhist text that he carried everywhere, into a fire. He said, "However deep one's knowledge of abstruse philosophy, it is like a piece of hair flying in the vastness of space; however important one's experience in things worldly, it is like a drop of water thrown into an unfathomable abyss. When insight comes, everyone disappears."
We can never find who we think we are, and yet we go through life so certain that we are something. Everything we do is in some way to enhance, protect, or secure this something that can never be located. This is the root of all delusion, because the "I"-thought is that concept in which all other ideas and concepts find refuge and significance. The unexamined "I"-thought becomes the hallucination called the separate self.
The problems in life that are created by the mind of the separate self issues of being, of meaning, of inner peace and happiness, of compassionate and intelligent action can never be resolved by the mind. These things are resolved with insight, when awareness emerges from the jungle of tension and thought. Then the mind will know the peace and security it is always failing to achieve in the outer world.
Ramana Maharshi said, "Self-inquiry leads directly to Self-realization by removing the obstacles which make you think that the Self is not already realized. Whatever be the means adopted, you must at last return to the Self: so why not abide in the Self here and now?"