Perhaps this philosophical coup d'etat may best be understood by comparing the Northern and Southern teachings. The discredited Northern school of Shen-hsiu had preached that the road to enlightenment must be traversed "step by step," that there were in fact two stages of the mind—the first being a "false mind" which perceives the world erroneously in dualities, and the second a "true mind" which is pure and transcends all discriminations and dualities, perceiving the world simply as a unity. One proceeds from the "false mind" to the "true mind" step by step, through the suppression of erroneous thought processes by the practice of dhyana or meditation, in which the mind and the senses slowly reach a state of absolute quietude.
The Southern school took issue with this theory of the mind on a number of points. To begin, they said that if there really is no duality in the world, then how can the mind be divided into "false" and "true"? They argued that the answer quite simply is that there is only one mind, whose many functions are all merely expressions of single true reality. The unity of all things is the true reality; our minds are also part of this reality; and upon realizing this, you have achieved the same enlightenment experience once realized by the Buddha. There is no "false mind" and "true mind," nor is there any need for a long program of dhyana to slowly suppress false thoughts. All that is needed is to practice "absence of thought" and thereby intuitively to realize a simple truth: One unity pervades everything. This realization they called Buddha-mind, and it could only happen "all at once" (not "step by step"), at any time and without warning. This moment of primal realization they called "seeing into one's original nature."
Although Shen-hui is somewhat vague about exactly what practice should replace meditation, the scholar Walter Liebenthal has inferred the following about Shen-hui's attitude toward "sudden enlightenment" as a replacement for meditation: "He seems to have rejected meditation in the technical sense of the word. Instead of methodical endeavors designed to promote religious progress he recommends a change of point of view leading to non-attachment. . . . Non-attachment in this case means that external objects are not allowed to catch our fancy.. . .
[A] thing recollected is isolated, it is singled out of the whole, and is thus an illusion; for all short of the undifferentiated continuum is illusive. The senses work as usual . . . but 'no desire is aroused.' . . . This change happens suddenly, that is, it is not dependent upon preceding exertions; it can be brought about without first passing through the stages of a career. That is why it is called 'sudden awakening.' "10
Liebenthal interprets Shen-hui as saying that whereas the purpose of meditation should be merely to erase our attachment to physical things, it also removes our cognizance of them, which is not necessarily a requirement for nonattachment. It should be possible for us to be aware of the world without being attached to it and enslaved by it. According to Shen-hui's sermon:
When thus my friends are told to discard as useless all they have learned before, then those who have spent fifty or more, or only twenty years practicing meditation, hearing this, might be very much puzzled. . . . Friends, listen attentively, I speak to you of self-deception. What does self-deception mean? You, who have assembled in this place today, are craving for riches and pleasures of intercourse with males and females; you are thinking of gardens and houses. . . . The Nirvana Sutra says, "To get rid of your passions is not Nirvana; to look upon them as no matter of yours, that is Nirvana."11
So far so good; but how do we reach this state of recognition without attachment? Apparently the way is to somehow find our original state, in which we were naturally unattached to the surrounding world. The way is to mentally disassociate ourselves from the turmoil of society that surrounds us and look inward, touching our original nature. In this way, both prajna and samadhi, awareness and noninvolvement, which have been described as the active and passive sides of meditation, are achieved simultaneously.
Now, let us penetrate to that state in which we are not attached. What do we get to know? Not being attached we are tranquil and guileless. This state underlying all motions and passions is called samadhi. Penetrating to this fundamental state we encounter a natural wisdom that is conscious of this original tranquility and guilelessness. This wisdom is called prajna. The intimate relation between samadhi and prajna is thus defined.
. . . If now you penetrate to that state in which your mind is not attached, and yet remains open to impressions, and thus are conscious of the fact that your mind is not attached, then you have reached the state of original blankness and tranquility. From that state of blankness and tranquility there arises an inner knowledge through which blue, yellow, red, and white things in this world are well distinguished. That is prajna. Yet no desires arise from these distinctions. That is samadhi.
. . . It follows that freedom from attachment (to external things, which replaces meditation in Ch'an Buddhism), enables you to look into the heart of all the Buddhas of the past, and yet it is nothing else than what you yourselves experience today.12