The Śūraṅgama Sūtra, Volume Three: The Eye Entrance Is the Wondrous True Suchness Nature of the Tathāgatagarbha

Original text: 复次阿难。云何六入。本如来藏。妙真如性。阿难。即彼目睛。瞪发劳者。兼目与劳。同是菩提。瞪发劳相。因于明暗。二种妄尘。发见居中。吸此尘象。名为见性。此见离彼。明暗二尘。毕竟无体。

Explanation: Furthermore, Ānanda, why are the six sense bases originally the wondrous true suchness nature of the tathāgatagarbha? Ānanda, it is precisely the activity-sign, laboring-sign, and operating-sign that appear when your eyes stare fixedly at objects. The eyes are the eye faculty, and the sign of fatigue is the aggregate of formations; both are laboring-contact signs manifested and operated by the wondrous bodhi. The eye faculty, relying on the two kinds of illusory sense-objects—light and darkness—makes contact with material sense-objects, and within this the seeing nature of the eye arises. The seeing nature absorbs these sense-objects, thereby manifesting them; this is called the seeing nature. Apart from the two kinds of illusory sense-objects of light and darkness, this seeing nature fundamentally has no body of seeing.

From the very beginning, the Buddha expounded how the six sense bases are the wondrous true suchness nature of the tathāgatagarbha. That is to say, the six sense bases in their entirety are produced by the tathāgatagarbha; they are the functional attributes of the tathāgatagarbha. Therefore, from within the six sense bases one can discover the functions and operations of the tathāgatagarbha and realize the tathāgatagarbha. The activity-signs and laboring-contact signs of the eye faculty and the manas are the wondrous true suchness nature; the seeing nature that is produced is the wondrous true suchness nature; moreover, the two conditions of light and darkness that give rise to the seeing nature are also the wondrous true suchness nature. What sentient beings see, contact, and make use of is all the wondrous true suchness nature—there is no dharma that is not the wondrous true suchness nature. Realizing the tathāgatagarbha is actually not difficult: His traces are everywhere, and He does not hide. The key lies in how a sentient being's own karmic obstructions stand—whether the causal conditions for seeing the nature are fully ripe, whether the bodhisattva nature is complete, and whether precepts, meditation, and wisdom are fully endowed. That is where the difficulty lies.

Original text: 如是阿难。当知是见。非明暗来。非于根出。不于空生。何以故。若从明来。暗即随灭。应非见暗。若从暗来。明即随灭。应无见明。若从根生。必无明暗。如是见精。本无自性。若于空出。前瞩尘象。归当见根。又空自观。何关汝入。是故当知。眼入虚妄。本非因缘。非自然性。

Explanation: Thus, Ānanda, you should know that this seeing nature does not come from the two signs of light and darkness, nor does it arise from the eye faculty, and it also does not arise from empty space. Why is this said? If the seeing nature were produced from brightness, then when darkness arrives, the seeing nature would vanish and cease to exist, and thus it could not see darkness, nor would it know darkness. If the seeing nature were produced from darkness, then when brightness appears, the seeing nature would disappear and be gone, and thus it could not see brightness. If the seeing nature were produced from the eye faculty, there would necessarily be no signs of light and darkness; such a seeing essence would fundamentally have no self-nature of its own. If the seeing nature arose from empty space, then looking forward it would perceive sense-object images, and upon returning it should be able to see the eye faculty; yet it does not see the eye faculty. Moreover, if empty space itself could see, what would that have to do with your eye faculty? Therefore, you should know that the eye base is illusory; it is fundamentally not produced by causes and conditions, nor is it a natural nature—it is rather the nature of the tathāgatagarbha.