Yunmen is reaching to the root of the problem. All dualities subdue each other, he is saying. Yet how? How is this so? When all dualities are seen through, when all opposites merge, where then is the illness? Who can speak of it? Seen through, there are no differences; in merging, there is nothing apart from it.

“The whole earth is medicine” is really the basis of all Buddhist practice. It’s a most profound and radical understanding. It revolutionizes the very core of all human experience. When we believe that what we perceive through our senses is the problem, then the solution seems to be to avoid those things that are difficult, or to close our eyes and pretend they’re not there. But this is not possible. This does not free us. This is to invest in the belief that we are hindered by life; life itself is the problem.

There’s a well-known story in which Manjusri asks Sudhana, who is picking medicinal herbs, to go find something which is not medicine. Sudhana looks and looks and comes back and says, “I cannot find anything that isn’t medicine.” Manjusri then says, “Bring me something that is medicine.” Sudhana reaches down and picks up a blade of grass. Manjusri says, “This piece of grass has the power to kill and to give life.”

The Great Way has no hindrance but we grasp at hindrances, which are all compounded forms. They’re all created in the minds of human beings. This does not deny that there is adversity in life; all creatures experience adversity: hunger, illness, predators. But within adversity, where is the hindrance? Who is the creator and who is the destroyer? When Yunmen says, “The whole earth is medicine,” he’s saying that all we perceive in life as the illness, this is the medicine. That’s why trying to seek freedom through avoidance or moving around can’t work. Everything we perceive as the hindrance is without hindrance, thus it is medicine. It does not hold the power to obstruct.

In Zen training, the student often perceives the teacher as the obstacle. The student wants something that the teacher is not providing. The teacher demands and challenges, pressing the student to find his or her own freedom. As students cling to their self-created cage, the teacher builds a cage around them. Until we take over responsibility for our own suffering, there will be no release and the teacher or the training will remain the problem. “The whole world is medicine, what is yourself?” To realize self-nature is to realize all things as medicine.

The commentary continues, “Right now this whole great earth is a profuse array of myriad forms, up to and including one’s own self. At once it’s medicine—at such a time, what will you call yourself? If you only call it medicine, even by the time Maitreya Buddha is born down here, you still won’t have seen Yunmen even in a dream. Ultimately, how is it? ‘Perceiving the meaning on the hook; don’t stick by the zero point of the scale.’” When a scale is stuck, its reading is not accurate. You can put something on the scale and get a measurement, but it’s not in accord with the truth.

There is no fixed form. If you say the world is only illness, then you ignore self-nature which has no characteristics. If you say the world is only medicine, then you ignore the suffering. In the poem Zuedou says, The whole earth is medicine: Why have ancients and moderns been so mistaken? and he tells a story about old master Tamei who was dying as his sangha gathered around him. Tamei said, “Coming, there is nothing to look to. Going, there is nothing to pursue.” Just at that moment, he heard the chatter of a squirrel outside the window and said, “It’s just this thing, not anything else. Keep it well. I’m going to go.” Then he died.