This is all we do in meditation. Sometimes I “nudge” the practitioners, during sitting, “What hears that? What sees this breathing… happening…? What is the witness?” and “Leave thinking alone — let it pass. Like sounds. Rather, turn: ‘what’ notices the thinking, coming and going… happening…? What is this witness?”
And when you do that, it opens up — vast boundlessness, with no thing or place or description. Indescribable and borderless, devoid of any quality or ground — we can say it is our original home, the Unborn, whatever. But these are also merely more mistaken words and damnable names and terms. Better off just leaving it alone!