Karin Ryuku Roshi takes up case 20 in the Book of Serenity:

Dizang asked Fayan, “What are you up to these days?”

Fayan said, “I’m wandering at random.”

Dizang said, “What do you expect from wandering?”

Fayan said, “I don’t know.”

Dizang said, “Not knowing is most intimate.”

Karin Roshi comments:

“I don’t know” is actually the absence of any form of identification. It contains both knowing and not knowing, and yet does not stand opposed to either. It takes off our clothes, removes our possessions, even our skin, our hair color and eyes. It’s laying down the karmic burden of our life that we drag around constantly, like a bag of rocks.