I have noticed that I seem to spend a great deal of time trying to "clarify" my posts (and comments) concerning what is, in my view, a universal element in the classic teachings of Zen Buddhism on nonduality and emptiness. Rather than continuing to repeat the same thing, I am posting this overview to serve as a topic in itself, and also as a link to clarify my position elsewhere.
It is a Zen axiom that the sole value of any Buddhist doctrine or method is wholly, and proportionately, dependent on its actual soteriological effectiveness. This principle is based on the recognition that all terms, systems, methodologies, and conceptual constructs are no more than methodological designations. In fact, according to Zen, all designations (methodological or otherwise) are nonsubstantial (i.e. they are not "independent entities," but are in fact interdependent).
The practical application of this axiom by contemporary Zen Buddhists is often evident concerning a number of Buddhist doctrines and methodologies (e.g. doctrines of karma and the Bodhisattva, and the methodologies of devoting merit and bowing), but is nearly absent in others. This absence is particularly conspicuous concerning doctrines that apply the soteriological methods of nonduality (e.g. emptiness and form, practice and realization, Buddha and ordinary being, delusion and enlightenment, etc.). This may be partly due to the complexities of using methodological designations that are inherently self-referential (applicable to themselves), like the "emptiness of emptiness" and the "nonduality of nonduality."
Yet it is this principle, as revealed in the Prajnaparamita literature, that even allows for the possibility of "explanations" to be effective (or not). This is the insight of the Madhyamika as elucidated by the Indian Buddhist master, Nagarjuna (acknowledged in Zen tradition as an ancestor).
As Nagarjuna says in his examination on The Four Noble Truths:
Whatever is dependently co-arisen
That is explained to be emptiness.
That, being a dependent designation,
Is itself the middle way.
MMK XXIV:18 (Trans. Jay L. Garfield)
It is significant to note that one of the first (maybe even the first) things Dogen wrote upon his return from China was a commentary on the Heart Sutra that specifically singled out how the effectiveness of teachings, or "explanations" was precisely proportionate to their emptiness:
"In the order of Sakyamuni Tathagata there is a bhiksu who secretly thinks "I shall bow in veneration of the profound prajna-paramita. Although this state there is no appearance and disappearance of real dharmas, there are still understandable explanations of all precepts, all balanced states, all kinds of wisdom, all kinds of liberation, and all views…
The bhiksu's secretly working concrete mind at this moment is, in the state of bowing in veneration of real dharmas, prajna itself - whether or not [real dharmas] are without (empty of) appearance and disappearance - and this is a venerative bow itself. Just at this moment of bowing in veneration, prajna is realized as explanations which can be understood: [explanations] from precepts balance, and wisdom, to saving sentient beings, and so on. This state is described as being without (empty). Explanations of the state of being without (emptiness) can thus be understood. Such is the profound, subtle, unfathomable prajna-paramita."
Shobogenzo, Maha-prajna-paramita, (Trans. Gudo Nishijima & Mike Cross)
Failing to realize, apply, and maintain an accurate perception, or "right view" of this fundamental principal is one of the primary causes for the misunderstanding and misrepresentation of Buddhist doctrines and methodologies. Nevertheless, while Zen (and most other Mahayana schools) acknowledges the validity of this revelation, it is not the only implication of the teachings on emptiness. The earliest records of Zen acknowledge the validity of the Huayen teachings of mutual identity, interpenetration, and non-obstruction of the universal and the particular (and among all particulars), as outlined in the pinnacle teaching’s of Li (universal) and Shih (particular).
The Huayen metaphors, On The Golden Lion, and, The Net of Indra, are perhaps the most well known illustration of this teaching by the Huayen ancestors (the fifth of which, Tsung-mi, is also acknowledged as an ancestor of Zen).
Perhaps lesser known is the Huayen teaching that Zen Master Dogen adapted in his own writings called the, Non-Obstruction of Concealment and Disclosure, by the Huayen ancestor, Ch’eng Kuan. A passage from the prologue on this teaching reads:
On the eighth day of a [lunar] month, half of the moon is bright and the other half is dark; the very appearance of the bright part [the disclosed] affirms but does not negate the existence of the hidden part. Likewise, the manifestation of something always implies the existence of the unmanifested or concealed part of the same thing (italics mine). At the moment when the bright part of the moon is disclosed, the dark part also "secretly" establishes itself. This is the reason for the so-called simultaneous establishment of concealment and disclosure…
(Trans. Garma C. C. Chang)
Students of Dogen will immediately recognize Dogen’s adaptation of this teaching in his essay Shobogenzo, Genjokoan: "As one side is illumined, the other side is darkened." Yet, this teaching permeates the entirety of Shobogenzo. It is explicitly used in Dogen’s teachings on practice and enlightenment, the expressible and the inexpressible, Buddha and ordinary being, original (sudden) enlightenment and acquired (gradual) enlightenment, speech and silence, nonduality and duality, past and present, and others. So permeated are Dogen’s writings (especially Shobogenzo) by this principal that any failure to account for it will undoubtedly lead to a misunderstanding of Dogen’s meaning.
While Dogen’s work comprises, by far, the largest corpus of English translations of Zen writings employing this principle, most of the classic records of Zen use it to a greater or lesser degree. It is the foundation of a number of Zen devices, such as the "Four Shouts", and the positions of "Guest and Host" associated with the Rinzai School, and the "Five Ranks" associated with the Soto.
Lacking a basic understanding of these methodologies can lead to some serious misunderstandings of Zen (and indeed any Mahayana School) expressions. Some of the most common manifestations resulting from the misunderstanding and misapplication of the liberative tools of nonduality as they apply to the doctrines on emptiness are:
A tendency to confuse "dualism" with "duality," leading to views that posit emptiness as "real," and form as "unreal."
Related to the first is the conceptualization of emptiness as truly and absolutely separate (or "other") than form (hence separate from the myriad dharmas, including us).
Concepts regarding emptiness as real (and separate from the myriad dharmas) arouse views of emptiness as "something" that can be attained (through prajna, intuition, or some form of practice).
Or, concepts of emptiness become reified, idolized and raised (as if upon a pedestal) above form (the myriad dharmas), reducing everything to a mere conceptualization of emptiness, which is often posited as a kind of "Supersymmetry" where all distinctions lose their significance.
Resulting in a loss of dynamism, creative imagination, authentic practice, intellectual development, reasoning, art, and the real characteristics, of charisma, zeal, and zest for the Dharma that is displayed in the records of the great Zen masters like Bodhidharma, Dogen, Hakuin, Huineng, and Ryokan. All of which is reduced into the bland, dull, flavorless soup of "oneness."
Leading to abandonment of authentic practice, justified with smug, self-assurances of "realization" that is really a mere contentment with conceptualized notions of oneness (rather than the actual experience of the infinite dynamic potential of authentic "Vast and Fathomless Unnamable Void").
Which finally manifests in forms of antinomianism (as is evidenced in many of the major western "Zen centers" where exploitation and violation of precepts are dismissed as the "enlightened behavior" of "crazy wisdom").
While the misunderstanding of any teaching can have negative results, the misperceptions concerning doctrines of nonduality and emptiness are especially effective in stifling genuine aspiration, zeal and affirmation for the Dharma. This is, of course, not the zeal of ambition or personal gain, but the true joyous realm of what Dogen calls "self-fulfilling samadhi." It is the "play," (in both senses of the word) of the universe itself. It is "Dharma enacting Dharma." In the words of the Large Sutra of Perfection of Wisdom:
What is the liking for the Dharma? The wish, the eagerness for Dharma. What is the delight in Dharma? The pleasure in Dharma. What is fondness for Dharma? The appreciation of its qualities. What is devotion to Dharma? The developing, the making much of that Dharma.
The Large Sutra of Perfect Wisdom, p. 104, Edward Conze
The records of Zen indicate how the nonduality of emptiness and form are fused in Manjusri’s sword of wisdom, that each of us take up with the Four Great Vows. Dogen says, it is difficult to cut into one. Emptiness and form are cut into one by the razor-sharp sword of case 100 in the Blue Cliff Record.
A monk asked Haryo, "What is the razor-sharp sword?"
Haryo said, "Each branch of coral supports the moon."
Master Tozan went around visiting the teachers of his day, to test and sharpen his own "sword." As he was taking leave of Nan-yuan, they had the following dialogue:
Nan-yuan said, "Make a thorough study of the Buddha Dharma, and broadly benefit the world."
The Master said, "I have no question about studying the Buddha Dharma, but what is it to broadly benefit the world?"
Nan-yuan said, "Not to disregard a single being."
The Record of Tung-shan, p.31, Trans. William F. Powell
According to one of Tung-shan’s verses on the Five Ranks, as we become more dexterous at wielding this sword, we activate "a natural determination to ascend the heavens." This is the inspiration that the Mahayana doctrine on the "Four Prajnas of Buddhahood" affirms as the inevitable effect of the realization of Buddha nature, concerning the third prajna (Observing Prajna) which closely corresponds to the fourth of the "Five Ranks" of Tung-shan.
Beyond this, the Zen masters indicate that, while we cannot help but rejoice at the freedom and boundless wealth of the fourth rank, another marvel remains. At the interface of the fourth and fifth ranks, the fourth prajna of Buddhahood—Practical Prajna—begins to function. The reality of total and absolute liberation. Dogen describes this as, "When Buddhas are Buddhas, they do not know they are Buddhas."
In Practical Prajna, wisdom and compassion are spontaneously manifested beyond intention, and convention. The fifth of the Five Ranks calls it: Arriving within Together. The verse for this rank is:
Falling into neither existence nor nonexistence, who dares harmonize?
People fully desire to exit the constant flux;
But after bending and fitting, in the end still return to sit in the warmth of the coals.
The Record of Tung-shan, p.31, Trans. William F. Powell