Japanese Zen Buddhist Philosophy (Stanford Encyclopedia of Philosophy)

Zen maintains a stance of “not one” and “not two,” that is “a position-less position.”

• “not two” means negating the dualistic stance that divides the whole into two parts.
• “not one” means negating the non-dualistic stance occurring when the Zen practitioner dwells in the whole as one, while suspending judgment in meditation. 
• the free, bilateral movement between “not one” and “not two” characterises Zen’s achievement of a personhood with a third perspective that cannot, however, be confined to either dualism or non-dualism, neither “not one” nor “not two”.

Zen recommends that its practitioner follow a three-step procedure: adjusting one’s body, breathing and mind.

To adjust the mind  means that the practitioner consciously moves to enter a state of meditation. 

He learns to disengage him- or herself from the concerns of daily life by the immobile bodily posture and the breathing exercise.

Meditation trains one to sit face-to-face with one’s self, while creating a psychological isolation from the external world.

This mechanism is the same as when one has a dream at night when the level of consciousness is lowered.

No-mind does not mean:

• a mindless state,
• that there is no mind

No mind means that there is no conscious activity of the mind that is associated with ego-consciousness.

No-mind is a free mind that is not delimited by ideas, desires, and images.

If the term “philosophy” is taken to mean the establishment of “the kingdom of reason",  Zen is an anti-philosophy.

Reason is incapable of knowing and understanding in toto what reality is.

Physical nature and human nature must be sought in an experiential dimension.