Sokuzan’s talk is inspired by Yogacara teachings on The Three Natures: the imaginary, the dependent, and the fulfilled. He references a verse from “The Teachings of the Three Own Beings” by Vasubandhu, a fourth century Indian Buddhist scholar-monk:

“The constant state of not being found of “how it appears” in that which appears, can be known as the fulfilled own being…”

https://www.youtube.com/watch?v=MDt3rbC3iBY