Here's an example: someone says, "Master, please hand me the knife," and he hands them the knife, blade first. "Please give me the other end," he says. And the master replies, "What would you do with the other end?" This is answering an everyday matter in terms of the metaphysical. When the question is, "Master, what is the fundamental principle of Buddhism?" Then he replies, "There is enough breeze in this fan to keep me cool." That is answering the metaphysical in terms of the everyday, and that is, more or less, the principle zen works on. The mundane and the sacred are one and the same.