The method to be practiced is as follows: you are to doubt regarding the subject in you that hears all sounds. All sounds are heard at a given moment because there is certainly a subject that hears. Although you may hear the sounds with your ears, the holes in your ears are not the subject that hears. If they were, dead men would also hear sounds.... You must doubt deeply, again and again, asking yourself what the subject of hearing could be.
Pay no attention to the illusory thoughts and ideas that may occur to you. Only doubt more and more deeply, gathering together in yourself all the strength that is in you, without aiming at anything or expecting anything in advance, without intending to be enlightened and without even intending not to intend to be enlightened; become like a child within your own breast... But however you go on doubting, you will find it impossible to locate the subject that hears.
You must explore still further just there, where nothing is to be found. Doubt deeply in a state of single-mindedness, looking neither ahead nor behind, neither right nor left, becoming completely like a dead man, unaware even of the presence of your own person. When this method is practiced more and more deeply, you will arrive at a state of being completely self-oblivious and empty. But even then you must bring up the Great Doubt, "What is the subject that hears?" and doubt still further, all the time being like a dead man.
And after that, when you are no longer aware of your being completely like a dead man, and are no more conscious of the procedure of the Great Doubt but become yourself, through and through, a great mass of doubt, there will come a moment, all of a sudden, at which you emerge into a transcendence called the Great Enlightenment, as if you had awoken from a great dream, or as if, having been completely dead, you had suddenly revived.
{Sermons of Takusui}
"awareness is prerequisite to all acceptable changes of theory"
Thomas Kuhn