The Śūraṅgama Sūtra, Volume Three: The Mind Faculty as the Wonderful True Suchness Nature of the Tathāgatagarbha

Original text: 阿难。譬如有人。劳倦则眠。睡熟便寤。览尘斯忆。失忆为忘。是其颠倒。生住异灭。吸习中归。不相踰越。称意知根。兼意与劳。同是菩提。瞪发劳相。因于生灭。二种妄尘。集知居中。吸撮内尘。见闻逆流。流不及地。名觉知性。此觉知性。离彼寤寐。生灭二尘。毕竟无体。

Explanation: Ānanda, for example, when a person becomes fatigued and weary, he falls asleep; when he has slept sufficiently, he wakes up. When (the manas) contacts sense objects, (the mind consciousness's) recollection arises; when the recollection cannot be brought forth, it is called forgetting. This is the inverted mark of arising, abiding, changing, and ceasing in which the manas dwells. The manas draws these marks of sense objects into its own mind, one mark of a sense object following another, in orderly sequence without confusion; this is called the mind-knowing faculty (manas). The manas and the mark of wearied contact when the manas contacts mental sense objects (dharmāyatana) are both wearied marks manifested and revealed by bodhi. Relying on the two kinds of illusory sense objects of arising and ceasing, the manas, in contact with mental sense objects, gives rise to the mind consciousness's knowing nature, drawing in the marks of mental sense objects within the manas-mind, producing the nature of seeing and the nature of hearing; the mind chases mental sense objects externally, never knowing where the mental sense objects come from, unable to awaken to the source of all dharmas — this is called the knowing nature. Apart from the two kinds of sense objects of sleep and waking, and of arising and ceasing, this knowing nature ultimately has no self-nature of its own.

The manas is one of the six faculties, and the mark of wearied contact with mental sense objects is the aggregate of volitional formations; both are illusory marks manifested by bodhi. When the body becomes weary, the manas arranges for sleep, and the mind consciousness ceases; after resting well, one wakes up, and the mind consciousness appears with its knowing nature. When the manas grasps at sense objects, the mind consciousness recollects; when the recollection cannot be brought forth, it is forgotten, called loss of memory. This knowing nature of the mind consciousness arises due to these two kinds of sense objects: falling asleep and waking, and arising and ceasing. After falling asleep, when the manas does not gather in marks of sense objects, the mind consciousness ceases; when the manas gathers in marks of sense objects, the mind consciousness appears and wakes up. Among these, the manas is inverted, constantly grasping at marks of sense objects, taking them as real, causing the mind consciousness to arise and cease moment by moment, knowing all dharma-marks externally, never knowing the source of these dharma-marks. If there were no such two kinds of illusory sense objects as sleeping and waking, and arising and ceasing, there would be no knowing nature of the mind consciousness. Seeking dharmas outside the mind is going against the stream of dharmas; only by seeking within the mind, going with the stream of dharmas, can one know the source of dharmas and thereby awaken to the Way.

Original text: 如是阿难。当知如是。觉知之根。非寤寐来。非生灭有。不于根出。亦非空生。何以故。若从寤来。寐即随灭。将何为寐。必生时有。灭即同无。令谁受灭。若从灭有。生即灭无。谁知生者。若从根出。寤寐二相。随身开合。离斯二体。此觉知者。同于空华。毕竟无性。若从空生。自是空知。何关汝入。是故当知。意入虚妄。本非因缘。非自然性。

Explanation: Thus, Ānanda, you should know that this faculty of knowing sense objects does not come from sleeping and waking, does not exist due to arising and ceasing, does not emerge from the manas-mind, and is not born from empty space. Why? If this knowing nature arose from the waking state, then when one falls asleep, the knowing would vanish — then who would know the sleeping? If the knowing nature emerged from the mental sense object of sleep, then upon waking it would vanish — then who would know the waking? If the knowing nature emerged when dharmas arise, then when dharmas cease, the knowing nature would vanish — then who could feel the ceasing of dharmas? If the knowing nature emerged from the ceasing of dharmas, then when dharmas arise, the knowing nature would vanish — then who would know the arising of dharmas?

If the knowing nature emerged from the manas, the manas does not have the two mental sense objects of sleeping and waking; the knowing nature, following the attributes of the manas, would necessarily be unaware of sleeping and waking. Sleeping and waking appear following the closing and opening of the body: opening is waking, and closing is sleeping. Apart from these two bases of sleeping and waking, this knowing nature would be like a flower in empty space, fundamentally nonexistent. If the knowing nature were born from empty space, then it would certainly be empty space itself that knows — what would that have to do with the manas's taking in of mental sense objects? Therefore, you should know that the entrance of the manas is illusory; it is fundamentally not born from causes and conditions, nor does it exist naturally, but is the tathāgatagarbha nature.