In Shoji, Dogen says:
It is a mistake to understand that we move from birth to death. Birth is a position at one time and it has its own before and after. Therefore within Buddha-dharma it is said that birth is no-birth. Death is a position at one moment and it has its own before and after. Therefore, it is said that death is no-death’(from Okumura, adapted)
If enlightenment is a universal quality not a personal one, the question we have to answer is how the sediment of the Self darkens the world.
In this passage Dogen answers the questions. If we assume the continuity of the Self then we assume linear time. If we assume that, then time is a kind of steamroller, crushing and extinguishing what we call ‘the past’.
If, however, we see from the perspective of Indra’s Net, then every event maintains its dharma position as part of the infinite fabric of Being Time. Or, as Dogen says in Uji, we are standing at the top of the mountain at this moment and look out in every direction to endless mountains.
 Also from Okumura (on the Genjokoan):
“It is a mistake to think that life turns into death. Life is a position at one time with its own before and after. Consequently, in the buddha dharma, it is said that life is itself no-arising. Death is a position at one time with its own before and after. Consequently, it is said that death is itself no-perishing. In life there is nothing other than life. In death, there is nothing other than death. Therefore, when life comes, just live. And when death comes, just die. Neither avoid them nor desire them.”