When the Upanishads address you and declare: 'Thou art That,' you should be very clear in your mind what the term 'Thou' implies. Then alone, when this is grasped with clarity and subtle receptivity, can you truly and immediately understand what 'That' connotes and how this relationship of oneness is possible. If you think that by the term 'Thou' the Upanishads mean you who are listening with your ears and trying to understand with your mind and grasp with your intellect, then the very purpose of the declaration is thwarted. If to you the term 'Thou' still seems to mean a physical entity, that means that you are still identifying yourself with the body, mind and intellect. As long as you are still in that state of understanding yourself, the Upanishads have failed in their mission, for they are not referring to this thou.
When the Upanishads say 'Thou,' they are not using human language but are trying to convey a divine experience. They are neither using Sanskrit, English, Hindi nor any other language. They are declaring an experience that is imponderable, beyond the knowing of the mind or the grasping of the intelligence, "whence all speech turns back with the mind, not reaching It." So, if instead of trying to understand the term 'Thou' upon that level-where mind and speech cannot enter and they came back unable to comprehend It-and you persist in taking it to mean a physical and psychological level, then the inner implication of 'Thou' has not yet dawned upon you. They are not saying that 'Mr. So and So' is Brahman. That is an absurdity.
Therefore, you first have to understand what this 'Thou' is that they are referring to when they declare that 'Thou art That.' They are not referring to the you that is seen, the you with name and form. They are referring to the unseen You. They are not referring to anything whatsoever that is seen; they are referring to YSou as the hidden, unknown seer of all thing seen, the knower of all things known. In that dimension, Thou, the hidden seer of all things seen, art That, that which alone prevails. That verily is your source, your alpha and omega-You, the unseen You, who may know the world, but the world can never know You. Even your father and mother cannot know You unless they themselves have already understood the true meaning of 'Thou Art That.' There is a need for long study, the need of sitting at the feet of a knower of Brahman and listening to what he has to say about Brahman, about maya, about yourself and about your relationships. You must listen, reflect and meditate. They say Rome was not built in a day. God is not understood even in one lifetime, what to speak of a day. Yet they say He can be realised within a twinkling of an eye. How can we reconcile these statements?
If a dry match is struck against a rough surface it will immediately burst into flame, but you cannot do that with a toothpick or a cake of soap. Consider the amount of work and the number of steps that go into the manufacture of a match head. Thus, when the interior of a seeker is ready, fully prepared through years of study, listening to the truth and pondering over what has been studied, ultimately when the Upanishads declare to you 'That art That,' you know perfectly well what is implied, what is meant by 'Thou.' "I am the unchanging fourth state of consciousness, calmly witnessing the ever-recurring cycle of waking dreaming and sleep. I am that I am! Awareness is my name." It is this meaning that the Upanishads are trying to address. They say that it is the subtlest of all subtle things. You must make your consciousness attain this subtlety. If it is still involved in dualities, in likes and dislikes, joy and grief, and identification with the body, how can that level be attained?
One sage said that grasping this truth is like chewing on steel peanuts and digesting them. It is not a little thing. There is a need for humility, for clarity of thought, for clearly understanding what this truth is and where you stand. Then humbly, with patience, diligence and fortitude try to move towards it and keep on moving. Make your life this slow movement, never allowing anything to divert you. This is sadhana, this is spiritual life, this is yoga, this is abhyasa (practice), this is meditation-dwelling on it, contemplating on it all twenty-four hours of the day. Meditation is throughout the day and night, even when you are working or serving or in a crowd. If the meditation stops, your sadhana has stopped, and your progress has stopped. You may be alone inside your meditation room, but in thought you may be in the middle of the world. Therefore, this is not play; it is not an ordinary thing. It requires humility and a clear understanding of your real identity. Then a positing of the question of 'Thou' is not ridiculous. Let us fully understand. Let us first assess our present state and see where we are. Then let us do all that is needful to reach where we ought to be if we want to understand Reality, if we want to grasp the Truth.