The Tso-ch'an of "Outer Paths" 外道禪
In his Liusu t'an ching 六祖禪經, The Platform Sutra, Hui-neng 惠能 says that if one were to stay free from attachment to any mental or physical realms, and to think of neither good nor evil, that is, refrain from discriminating, neither thought nor mind will arise. This would be the true "sitting" of Ch'an. Here, "sitting", not limited to mere physical sitting, refers to a practice where the mind is not influenced, disturbed, or distracted, by anything coming up, whether internally or in the environment. If you were to experience your self-nature, this would be called "Ch'an" (Kensho in Zen). To see self-nature is to see one's own unmoving Buddha-nature, and is the most fundamental level of enlightenment. Without tso-ch'an in this sense, one cannot attain Ch'an. Hence tso-ch'an is the method, Ch'an the result. Since Ch'an is sudden enlightenment, when it occurs, it is simultaneous with tso-ch'an.
Hui-neng was critical of certain attitudes in practice which did not conform to his criteria of the true tso-ch'an which leads to Ch'an. These practices are referred to as "outer path" tso-ch'an because they are also found in other disciplines, for example, Taoism. A couple of anecdotes will illustrate some of these not-Ch'an attitudes in tso-ch'an.
The first anecdote involves a disciple of Hui-neng's Nan-Yueh Huai-jang 南嶽懷讓(677-744). Huai-jang observed a monk named Ma-tsu 馬祖 (709-788) who had a habit of doing tso-ch'an all day long. Realizing this was no ordinary monk, Huai-jang asked Ma-tsu, "Why are you constantly doing tso-ch'an?" Ma-tsu answered, "To attain Buddhahood." Huai-jang picked up a brick and started rubbing it vigorously. After a while, Ma-tsu asked, "What are you doing?" Huai-jang said, "I'm making a mirror from this brick." Ma-tsu said, "That's absurd. You can't make a mirror from a brick." Huai-jang said, "Indeed. And how is it possible to become a Buddha by doing tso-ch'an?" Thereupon, Ma-tsu asked, "What should I do?" Huai-jang said, "When the ox won't pull the cart, do you beat the cart or the ox?" Ma-tsu did't know how to reply. So Huai-jang said, "Are you doing tso-ch'an to attain Ch'an or to become a Buddha? If it's Ch'an, Ch'an is neither sitting nor lying down; if it's Buddhahood, the Buddha has no form. Since the Dharma has no abiding form, there should be no grasping, nor rejection. Being attached to sitting, not only are you not becoming a Buddha, but you are killing the Buddha." Ma-tsu became a disciple of Huai-jang and later, a great master.
The meaning of this story is that true tso-ch'an is not just a matter of sitting, however perfected and dedicated. Some people may do tso-ch'an in this way and may get some benefits. But to attain Ch'an by perfecting the external form, or the physical aspect of tso-ch'an is impossible. Enlightenment begins with introspection, in what Huai-jang 懷讓 called hsin-ti 心地, the method of the mind-ground. The word "ground" is used here to mean "everything can grow form this ground." Thus, self-nature is to be found not in the realm of form, nor through self-cultivation, but in the mind-ground.
Ma-tsu 馬祖 himself later evolved the concept of p'ing-ch'ang hsin 平常心, or "ordinary mind." One sense of Ma-tsu's "ordinary mind" is mind which is involved in the ordinary world, and moves as usual, but is not attached to anything. Another sense comes from the root meanings of the words p'ing 平 and ch'ang 常, and can be construed to mean a mind which is "level" and "constant", that is, in a state of constant equanimity. In either sense, there is no attachment. So the point is, the kind of tso-ch'an that Ma-tsu did before he met Huai-jang emphasized physical aspects at the expense of being grounded in mind.
The second "outer path" anecdote also involves disciples of Hui-neng. When Shih-t'ou Hsi-ch'ien 石頭希 遷(700-790) was a young monk, he approached the dying Hui-neng and asked, "Master, after you pass away, what should I do?" Hui-neng said, "You should go to Hsing-szu". Shih-t'ou understood him to say hsun-szu 尋 思, which means "seek thoughts". This was actually a term for the method of meditating by watching one's thoughts. Shih-t'ou was unaware that there was another disciple of the Sixth Patriarch by the name of Ch'ing-yuan Hsing-szu 青原行思(?-740), so he just assumed that the master told him to practice watching his thoughts. After Hui-neng died, Shih-t'ou constantly sought out very isolated, quiet places and spent his time in tso-ch'an, neglecting all else. An elder in the assembly saw this and asked, "The master is dead; what are you doing here in empty sitting?" Shih-t'ou replied, "I am only following the master's instructions. He told me to watch my thoughts." The elder said, "You should realize you have an elder Dharma brother whose name is Hsing-szu. Why don't you hurry and go to study with him?"
Indeed, the tso-ch'an which consists in sitting in a quiet place, immersed in tranquility, is widely practiced. This kind of tso-ch'an, which Shih-t'ou practiced until he learned of his error, was also criticized by Hui-neng in the Ching-te ch'uan teng lu 景德傳燈錄, The Transmission of the Lamp. In it, he said, "If you hold the mind and contemplate silently, this is a disease and not Ch'an. Constantly sitting, restraining your body, how does this help the principle (of attaining enlightenment)?" Using this kind of tso-ch'an, one can enhance health and mental calmness, even attain samadhi. But for a practitioner who has become attached to such peaceful meditation, the habit can become an obstacle.
Both of these anecdotes are critical of certain kinds of attitudes in practicing tso-ch'an. Insofar as they are similar to "outer path" methods, they are not correct Ch'an. The masters were not critical of tso-ch'an itself, which is a necessary practice to make progress in Ch'an, especially for beginners. The great masters practiced tso-ch'an, even if they were sometimes critical of practitioners who had "Ch'an sickness." And most continued practicing even after becoming enlightened, sometimes very intensively.
In the Biography of Eminent Monks 高僧傳, it is said that Master Pai-chang Huai-hai 百丈懷海(720-814) established the design for the living quarters of his monastery. In the meditation hall there were long, connected sleeping platforms. Its purpose was for people who had been meditating for a long time to take a break and lie down. From this description we can infer that the intent was for monks to spend most of their time in tso-ch'an, and only minimal time in sleeping. This in spite of the fact that Pai-chang was a disciple of Ma-tsu, who as a master, advocated non-sitting methods. This same design was used in many future monasteries.
《TSO-CH'AN》p. 0015-0019