Perfect Interpenetration, interconnectedness or complete interfusion is a key philosophical concept in East Asian Buddhism, which was most prominently developed within the Huayan and Tiantai schools. It describes a kind of holism that sees every individual phenomenon (Sanskrit: dharma, Chinese: 事 shi) in the universe as simultaneously containing the entirety of all other phenomena, while also being contained within every other phenomenon. According to this view, this state of interpenetration exists without each phenomenon losing its individual identity in an undifferentiated monism.
The root of the East Asian idea of interpenetration is found in the Buddhist theories of Pratītyasamutpāda (dependent co-arising), emptiness and in the Mahayana doctrine of non-duality (advaya) as found in texts like the Avatamsaka Sutra. Though initially developed in the Huayan and Tiantai schools, the concept influenced all major traditions of East Asian Buddhism, including Chan / Zen and Pure Land. The idea is often illustrated through the influential metaphor of Indra's net popularized by the authors of the Huayan school.
Various traditional Chinese Buddhist terms are used to describe the idea that all things are interpenetrated, including interpenetration (Chinese: 通達; pinyin: tōngdá, from Sanksrit: prativedha), perfect interfusion (圓融; yuánróng), unobstructed perfect interfusion (圓融無礙), and mutual inclusion (互具; hu ju).Hamar, Imre (Editor) (2007). Reflecting Mirrors: Perspectives on Huayan Buddhism, p. 189. Asiatische Forschungen 151. Otto Harrassowitz Verlag. Western scholars often use terms like interconnectedness, interpenetration and interbeing, the last term having been coined by the modern Zen teacher Thich Nhat Hanh.
The doctrine of interpenetration is often used as a bridge between Buddhist metaphysics and practical ethics. By realizing that all beings are inextricably linked, the practitioner is led toward universal compassion. This is because the suffering and happiness of a single individual is seen as inseparable from the suffering of the whole, and vice versa. In the modern era, the idea has become widespread in Buddhist modernist discourse, which emphasizes the ethical, environmental and political implications of the doctrine. It is frequently cited in discussions regarding Buddhist ecology and engaged Buddhism, where it provides a spiritual framework for understanding the deep ecological interdependence of the natural world and human beings.McMahan, David. (2009). "A Brief History of Interdependence." 10.1093/acprof:oso/9780195183276.003.0006.
In East Asian Buddhism
The Chinese Buddhist philosophical idea that everything is connected to everything began to develop during the Sui and Tang dynasties (581–907 CE), a period that has been seen as a golden age for Chinese Buddhism. The source of these ideas are found in Indian Mahayana writings on emptiness (especially in the works of Nagarjuna) and in key Mahayana sutras like the Avatamsaka Sutra. These ideas were synthesized and developed further by Chinese Buddhist philosophers like Zhiyi (c. 538–597 CE), Jizang (c. 549–623), Dushun (c. 557–640) and Fazang (c. 643–712) into complex metaphysical doctrines of holistic interpenetration.
Apart from drawing on Indic Mahayana sources, Chinese Buddhist writings on interpenetration may have also drawn inspiration from native Chinese sources. Charles Muller notes that writings like the I Ching, Analects, Tao Te Ching, and Chuang Tzu accept "a worldview in which the thoughts and actions of an individual penetrate, and carry influence throughout the entire world." Confucian and Daoist sources also use the terms 通 tōng and 達 dá, both of which could mean "apprehend," "understand," "grasp," "permeate," "fill," or "influence."
Huayan The Huayan (Avatamsaka) school is particularly known for its development of the theory of interpenetration, which is also known as "perfect interfusion" (圓融; yuanrong), the non-obstruction of phenomena (事事無礙; shishi wu’ai), and "the dependent arising of the whole realm of phenomena" (法界緣起, fajie yuanqi; Sanskrit: dharmadhatu pratityasamutpada). This doctrine is central to Huayan thought and is described in various ways throughout the writings of Chinese Huayan scholars, dating back to the founder of the school, Dushun.Hamar, Imre. "Chengguan's Theory of Four Dharma-dhātus Imre Hamar", Acta Orientalia Academiae Scientiarum Hung. Volume 51 (1-2), 1-19 (1998). Muller explains that the Chinese binome 通達 tōngdá "indicates both passing through that which is already open, and piercing through that which has been heretofore closed."
Huayan masters like Fazang and Chengguan developed this theory out of their interpretation of the doctrine of emptiness and their reading of the Avatamsaka Sutra. For them, all phenomena (dharmas) are mutually dependent on and interfused with each other as well as with the entire set of dharmas in the universe (the Dharmadhatu, "dharma realm"). As such, any individual dharma only exists as part of the cosmos as an interconnected nexus of dharmas, a system in which each dharma contains all other dharmas.Hamar, Imre (Editor) (2007). Reflecting Mirrors: Perspectives on Huayan Buddhism (Asiatische Forschungen), p. 189. This is described by Fazang with the phrases "one is many, many is one" (yi ji duo, duo ji yi) and "one in many, many in one" (yi zhong duo, duo zhong yi), which refers to how any dharma penetrates and is penetrated by the totality of all things.Cua, Antonio S. (2003). Encyclopedia of Chinese philosophy, pp. 254-257. Routledge. As Bryan Van Norden describes this theory, "because the identity of any one thing is dependent on the identities of other things, 'one is all,' and because the whole is dependent for its identity on its parts, 'all is one.'"Van Norden, Bryan and Nicholaos Jones, "Huayan Buddhism", The Stanford Encyclopedia of Philosophy (Winter 2019 Edition), Edward N. Zalta (ed.), URL = https://plato.stanford.edu/archives/win2019/entries/buddhism-huayan/ .
While the Avatamsaka Sutra does not itself expound the theory of interfusion as taught in Huayan, there are numerous passages which describe how each individual particle contains countless worlds within them, such as the following:
The idea may also have been influenced by the Gaṇḍavyūha Sūtra's climax scene in Vairocana's Tower.Yü, Chün-fang (2020). Chinese Buddhism: A Thematic History, p. 164. University of Hawaii Press. In this passage, the sutra's protagonist Sudhana enters a towered temple hall (kūṭāgāra) and sees that the inside of it is vast as the sky, containing hundreds of thousands of other kūṭāgāras that coexist without obstructing each other. Inside, he witnesses bodhisattvas (including Maitreya) entering samādhi, emitting countless transformation bodies from their skin pores, and hearing melodious Buddhist teachings emanating from every pore. In one especially magnificent tower, he perceives the entire Buddhist cosmos in one single glance, and within each world, he observes Maitreya's birth, descent to earth, and the key events of his final existence. As the Gaṇḍavyūha Sūtra'''s fifty fourth chapter states:He saw within the kūṭāgāra another hundred thousand with this kind of an array of adornments: adorned by countless precious parasols, banners, and flags, and so on, adorned by countless perfect excellent qualities. He saw that all those kūṭāgāras were in that way vast, immense, and immeasurable; were treasuries of space; and had been completely, beautifully adorned. He saw that these kūṭāgāras were perfectly arranged so that in a single perception they appeared in the manner of reflections that were separate from one another, not mingled with one another, and distinct from one another, and so that they appeared with all of them without exception being perceived in a single perception. Furthermore, a common theme of the Avatamsaka Sutra is how the Buddha's Dharma is "one" or singular, while the perceptions and understandings of all sentient beings are manifold. This is likened to how a luminous pearl can contain many reflections, and is used to explain how the Buddha's realm of nirvana manifests and suffuses all of samsara (highlighting the Mahayana doctrine of the non-duality of samsara and nirvana). These ideas led to Chinese exegetical discussions on the unity between the one (yi 一) and the many (duo 多) (as seen in Zhiyan's phrase “One is all” 一即一切), as well as further developments of the closely related Chinese philosophical theories like essence-function and the relationship between the ultimate principle (li) and the myriad phenomena (shi) — all of which were seen as interdependent and interconnected.
The Huayan theory of interpenetration was first presented in Dushun’s Threefold Discernment of the Dharmadhatu which provides a progressive meditative framework for understanding reality which moves from the classic Mahayana view of emptiness to a radical vision of cosmic interpenetration. Dushun begins with the first discernment, which establishes the classic identity between form and emptiness. The second discernment introduces the distinctive Huayan categories of li 理 (universal principle) and shi 事 (particular phenomena), arguing that these two dimensions of reality are mutually non-obstructive and pervade one another like water and waves. The third and highest discernment completely transcends the dualism of the ultimate principle and myriad phenomena, focusing on the total pervasion of shi with shi. In this final stage, reality is viewed as a groundless, center-less, fractal web where every individual dharma fully contains and is contained by every other thing in the universe.Gimello, Robert M. (1976). "Chih-Yen, (602-668) and the foundations of Huayan Buddhism", pp. 10-30. Dissertation: Columbia University