Sokuzan's talk is inspired by a line in Dogen's Genjokoan: "When you see forms or hear sounds fully engaging body-and-mind, you grasp things directly. Unlike things and their reflections in the mirror, and unlike the moon and its reflection in the water, when one side is illumined the other side is dark." (This translation is by Robert Aitken and Kazuaki Tanahashi)

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