Zazen is often called the mountain still state, the balanced state.
What we need to understand is that the state is momentary. It is a quality of this moment.
Not the person, the moment.
This moment rolls in and out of balance. When out of balance, self, world and linear time all arise, together. When in balance, it is not that the self and the myriad things are negated or affirmed but, as the shin jin mei tells us, they cease to exist in the old way.