To Cling to Knowledge and Views Is the Root of Ignorance; To Transcend Knowledge and Views Is Nirvana Itself

In the Śūraṅgama Sūtra, there is a passage: "When perception establishes perception, that is the root of ignorance; when perception has no perception, that is nirvāṇa." The phrase "when perception establishes perception, that is the root of ignorance" means that sentient beings all possess a mind of seeing, hearing, feeling, and knowing—they can see, hear, feel, and know. However, if we regard this knowing nature as real, establishing the knowing nature that perceives the six dust realms as true, as an eternal and indestructible self that can continue into future lives, then such a view is a wrong view and the fundamental root of ignorance. This causes one to revolve in the six paths of birth and death, unable to attain liberation.

"When perception has no perception, that is nirvāṇa." If, through contemplation and practice, we realize that these natures of seeing, hearing, feeling, and knowing are all deluded minds subject to birth, death, and change—impermanent, unable to exist forever, and not the true self—then in our hearts, we no longer recognize the nature of seeing, hearing, feeling, and knowing as the self. Once such knowledge and view are firmly established, the view of self is severed, and in the future, the attachment to self can be eradicated, leading to the realization of the nirvāṇa without residue. If, within seeing, hearing, feeling, and knowing, one realizes that inherently pure mind devoid of the nature of seeing, hearing, feeling, and knowing, then one attains the inherently pure nirvāṇa of the original nature.

To explain this passage more precisely: "When perception has no perception" means that alongside the various perceptions of the six consciousnesses, there exists the fundamental mind, the tathāgatagarbha, which has no perception whatsoever. It operates continuously in the background. "That is nirvāṇa" refers to this fundamental mind, the tathāgatagarbha, which is unborn and undying within the state of nirvāṇa—the nirvāṇa mind.