One day, Master Tenno Dogo asked Master Sekito Kisen: What is the fundamental principle of Buddhism?
Master Sekito said: It isn’t obtainable. It isn’t knowable.
Master Dogo said: Is there a more realistic expression?
Master Sekito said: The wide sky does not hinder the flying white clouds
A familiar instruction we’re given for zazen is to let thoughts come and go, like clouds in the sky. By “thoughts” we don’t just mean intentional thinking of course, but the full range of what we would ordinarily call mental phenomena: snatches of pictures, body sensations, auditory or visual hallucinations, feelings, waking dreams; the whole works.
But the implication in the instruction isn’t quite right, because the suggestion is that, with equanimity, these ‘thoughts’ will gradually fade away, and we’ll be left with a wide, empty and infinite sky.
It’s to counter that implication that Sekito answers as he does. Dependent origination isn’t just mountains and trees and waters and birds; it’s everything, including ‘thoughts’. And our task isn’t to uncloud the sky, but to actualise vast space, within which everything has its own expression, its own life.