The Method of Cultivating Dhyāna in the Sūtra of Perfect Enlightenment

若诸菩萨唯灭诸幻，不取作用，独断烦恼，烦恼断尽，便证实相，此菩萨者，名单修禅那。 

Chan (dhyāna) is a method of meditative cultivation aimed at realizing prajñā and awakening to true reality. How is true reality realized? It is realized when afflictions are completely severed. Afflictions are precisely all forms of ignorance; when there is no obscuration by ignorance, the wisdom of prajñā manifests, and true reality is necessarily realized. The Buddha said: All beings on earth possess the Tathāgata’s wisdom and virtuous marks, but because of afflictions and delusive thoughts they cannot realize it. The method of dhyāna accords with what the Buddha taught, taking the path of practice that severs afflictions in order to realize true reality. The bodhisattva’s method of severing afflictions differs from that of the non-Buddhists and of the arhats and pratyekabuddhas, because the bodhisattva knows that all dharmas are like illusions; therefore, within meditative cultivation he extinguishes all illusions—any illusory, unreal marks are extinguished and not grasped. Because he does not grasp at the illusory dharmas, afflictions are gradually severed, the mind attains purity (viśuddha), and he realizes the dharma of true reality, which is not illusory. 

Of course, afflictions cannot all be severed instantaneously, nor can true reality be realized in its entirety at once; there must be a sequence, steps, and a process. As more and more afflictions are severed, the realization of true reality becomes ever deeper, until afflictions are completely severed and true reality is realized in full, all the way to buddhahood. This means that to realize true reality to a certain degree, one must sever afflictions to that degree and remove obscuration to that degree. By severing the coarsest afflictions, one realizes the most initial prajñā of true reality; by severing the fundamental afflictions, one realizes the profound prajñā of true reality and realizes suchness (tathatā); by severing the habitual tendencies of afflictions, the realized suchness becomes ever deeper and ever truer. Therefore, without severing afflictions one cannot realize true reality. If not even the slightest trace of the coarsest afflictions has been severed, then self-view (ātma-dṛṣṭi) cannot be eliminated, and the prajñā of true reality cannot be realized either. 

Many people clamor that bodhisattvas need not sever afflictions, which is tantamount to saying that bodhisattvas need not realize prajñā or realize true reality—becoming wisdom-less bodhisattvas. Such beings are not true bodhisattvas, lacking the wisdom and virtue of a bodhisattva. A bodhisattva who does not wish to sever fundamental afflictions, and who still has coarse afflictions, is a totally bound ordinary being (pṛthagjana)—seemingly a bodhisattva but not a bodhisattva, lacking the demeanor and stature of a bodhisattva, not a model for sentient beings, unable to lead sentient beings toward liberation and to the farther shore of nirvāṇa.

The entire focus of practicing dhyāna alone lies in "only extinguishing all illusions, not taking up their functions." Illusory dharmas arise from causes and conditions, arising, ceasing, and changing; they have no substantive function. Therefore, having clearly recognized this point, the bodhisattva neither acknowledges nor grasps at illusory dharmas. Throughout the entire process of cultivation, he can eliminate self-view (ātma-dṛṣṭi), sever self-grasping (ātma-grāsa), sever grasping at dharmas (dharma-grāsa), realize true reality, realize suchness (tathatā), and realize non-abiding nirvāṇa (apratiṣṭhita-nirvāṇa). Not taking up the functions of illusory dharmas is precisely severing grasping at dharmas; when grasping at dharmas is completely severed, ignorance and afflictions are completely severed, and one realizes the non-abiding nirvāṇa (apratiṣṭhita-nirvāṇa) of the buddha-ground. The methods of practice of the non-Buddhists do not involve extinguishing all illusions, because they do not know that all dharmas are like illusions, nor do they know that the five aggregates (pañcaskandha) are illusory. If arhats and pratyekabuddhas have not studied and cultivated prajñā, they likewise do not know that all dharmas are like illusions; therefore they cannot extinguish the illusory dharmas, cannot refrain from grasping at the illusory dharmas, and cannot sever grasping at dharmas. Only bodhisattvas can sever grasping at dharmas; only bodhisattvas can become buddhas; only bodhisattvas can realize ultimate nirvāṇa.