‘If you try zazen, you will quickly realize that as long as you regard knowing and the self as the same, you cannot simply accept knowing as knowing. There will inevitably be a reaction against the contents of knowing and you will end up being dragged around by this. And then, you will end up forgetting the essential effort of upright sitting because the center of your intention will shift to managing the contents of knowing. Moment to moment in our zazen, we are standing at a crossroads: will we be deepening into zazen or will we become occupied with knowing? In most cases, little by little and without being aware of it (or while being aware of it), people tend to go tottering off in the latter direction. It is through fully tasting this difficulty in zazen, that we experience over and over again the strength, the depth, and the persistence of our habit to regard knowing and the self as being the same.
However, it isn’t possible for those of us who practice zazen to stagnate there. In any case, there is nothing else we can do except to make the effort over and over again of awakening from our infatuation with knowing by retracing our steps and heading in the direction of upright sitting. When our diligence bears fruit and gradually our zazen ripens, we will be able to distinguish between the condition of knowing and that of non-knowing (the totality of zazen equals the true nature of the self).
Then, upright sitting and knowing will no longer get involved in the habitual entanglements and confrontations and knowing will become of use to upright sitting. Actually, the root of the problem is not knowing itself, but rather the attitude we have toward knowing and the manner we deal with it. When this changes, then we are no longer disconcerted or manipulated by knowing. Rather, we will be able to use knowing as a key for regulating the body, breath, and mind, and in this way effectively make use of it in zazen. Furthermore, knowing will be an indispensable part of zazen that will merge and unite with it. In this way, knowing is fully integrated with zazen and it becomes zazen’s knowing (the knowing of “the actualization in nonthinking”) and then a new development will occur in knowing itself.’ (Polishing A Tile)