The Zen teachers have a very efficient technique for making all this happen. They first discredit rationality for a novice by making him feel foolish for using it. Each time the novice submits a rational solution to a koan, he receives a humiliating rebuff. After a while the strain begins to tell. In the same way that a military boot camp destroys the ego and self-identity of a recruit, the Zen master slowly erodes the novice's confidence in his own logical powers.
At this point his intuitive mind begins overcoming its previous repression. Distinctions slowly start to seem absurd, because every time he makes one he is ridiculed. Little by little he dissolves his sense of object and subject, knower and known. The fruit now is almost ready to fall from the tree. (Although enlightenment cannot be made to happen, it can be made possible.) Enter at this point the unexpected blow, the shout, the click of bamboo, the broken leg. If the student is caught unawares, rationality may be momentarily short-circuited and suddenly he glimpses--Reality.
The irony is that what he glimpses is no different from what he saw before, only now he understands it intuitively and realizes how simplistic and confining are rational categories and distinctions. Mountains are once again mountains; rivers are once again rivers. But with one vital difference: Now he is not attached to them. He travels through the world just as always, but now he is at one with it: no distinctions, no critical judgments, no tension. After all that preparatory mental anguish there is no apparent external change. But internally he is enlightened: He thinks differently, he understands differently, and ultimately he lives differently.
Ch'an began by working out the question of what this enlightenment really is. Prior to Ma-tsu the search was more for the nature of enlightenment than for its transmission. This was the doctrinal phase of Ch'an. As time went by, however, the concern shifted more and more from defining enlightenment--which the Ch'an masters believed had been done sufficiently--to struggling with the process. After Ma-tsu, Ch'an turned its attention to "auxiliary means" for helping along transmission: paradoxical words and actions, shouts, beatings, and eventually the koan.1