Therefore one must wait until the student's mind is settled, and then explode this settled, unified mind. I describe the process as starting with scattered mind, then using a method to unify the scattered mind into samadhi, and finally applying the method of Ch'an to dissolve the unified state. A scattered mind lacks the focus and energy necessary for this great event. It must first be collected and concentrated. Then, at that stage, you need the power of Great Doubt to cause a great explosion, and enter the enlightened state.

The unified mind is like a balloon. As you inflate it steadily with pressure, it will yield and expand. If you continue without letting up, at a certain point it will expand no more, and explode. So when the mind is in a unified state, it is ready to generate the Great Doubt. This doubt can be generated by the hua-t'ou-the great question that must be answered: "What is Wu?" "Who am I?" "What is my original face?" "What is the meaning of this kung-an?" But you must continue without stopping, without letting in stray thoughts. When you're blowing up a balloon, you can't blow a few breaths, then let the air out, then start up again. This way you'd never get it to stretch to the maximum point. When people are in samadhi they may feel that there is no mind, no thoughts. But even at that state there is a mind left. It's just that you are not aware of it. One is not aware of this sense of "large self." But you must lose even this to be genuinely enlightened. At that stage there is no problem of "small" or "large" sense of self, no more attachment or vexations, no more greed, hate, ignorance, pride, doubt. In the state of one-mind, there is still a sense of self. But after the explosion, even this sense of expanded self is gone, though everything still exists.