Essence-Function or Essence and Function, or else Substance and Function (體用, Chinese pinyin: tǐ yòng, Korean: che-yong) is a key concept in Chinese philosophy and other Far-Eastern philosophies (Japanese philosophy, Korean philosophy, Vietnamese philosophy).
The notions appear already in the Zhongyong (Doctrine of the Mean) attributed to Zi Si, the grandson of Confucius. The first philosopher to systematically use the ti yong schema for the analysis and explanation of deep relationships, was Wang Bi (226-249) in his commentary to Daodejing, chapter 22, when he discussed the metaphysical relation between non-being (wu) and being (you). Subsequently the notion has been borrowed from the Neo-Daoist philosophy to other schools of Chinese philosophy, including Hua-yen and other schools of Buddhism, and Neo-Confucianism of Cheng Yi and Zhu Xi, and served as a basic tool of interpretation of various philosophical relations in compound and dynamic events. With these schools it has travelled to Korea, Japan and Vietnam, and has been developed there. Wing-tsit Chan is one of the first scholars to open the discourse in English on this notion within the Chinese Neo-Confucian philosophy (in his Reflections on Things at Hand, 1967).
 The Awakening of Mahayana Faith, attributed to Aśvaghoṣa (?80-?150 CE), employs Essence-Function. Essence-Function forms a fundamental syncretic and ecumenical application in the philosophy of Wonhyo (617–686 CE). Chinul (1158–1210) and Kihwa (1376–1433) also employ and develop this idea of Essence-Function in their writings in particular ways. Wonch'uk (613–696) employed the conceptual and analytical tool, Essence-Function, as an exegetical, hermeneutical and syncretic device.
Nomenclature, orthography and etymology
體, this character is known as Radical 188 and romanized as "Tai" or "T'i" and is employed in both Cantonese and Mandarin written Chinese where it holds the semantic field:  [n] body  [n] shape; form  [n] entity; unit  [n] style; fashion; system  substance; essence  theory (as opposed to practice). Korean pronunciation is 체, or CHE using the MCT-2000 Romanization.
用, this character is known as Radical 101 and romanized as "Jung" or "Yung" and is employed in both Cantonese and Mandarin written Chinese where it holds the semantic field:  [v]use; employ; apply; operate  [v] exert  [n] use  effect  finance  [vn] need  [v] eat; drink  Kangxi radical 101. Korean pronunciation is 용, or YONG using the MCT-2000 Romanization.
Essence-Function (t'i-yung, 體用 : che-yong, 체용)
Wonhyo developed t'i-yung theory into its most influential form in his commentary on the Ta ch'eng ch'i hsin lun (Treastise on the Awakening of Mahayana Faith). This scripture proclaims the non-duality of the phenomenal or mundane world and the tathagata-garbha (considered equivalent to the one-mind of Yogacara). The Treastise Template:Quote
A tree, a pervasive living metaphor and mythical symbol throughout human cultures and icon of the branching, generation or lineage archetype, is employed as a teaching tool or hermeneutic device for explaining the relationship and operation of Essence-Function where 'Essence' the deep underlying ineffable cause are the "roots", and the 'Function' are the discernible effects, the "branches". Muller (2005: unpaginated) identifies the metaphor of the "roots" and "branches" as an analogue of Essence-Function within the Great Learning: "Things have their roots and branches, affairs have their end and beginning. When you know what comes first and what comes last, then you are near the Way."
Doctor (2004: p. 101) renders into English a quotation from Mipham (1846–1912) which has the metaphor of 'roots' and 'branches'. Mipham, familiar with Woncheuk's Saṃdhinirmocana-sūtra commentary (known in Tibet as the Great Chinese Commentary as it was referred to by Tsongkhapa) that employs essence-function, includes in his Commentary to the Madhyamālaṃkāra of Śāntarakṣita an open quotation from the 'Mother of the Victorious Ones' (Sanskrit: Prajñāpāramitā):
Yet although it is definitely necessary to embrace general learning and reflection, it is meaningful to condense one's practice to its core. The Mother of the Victorious Ones give examples of those who abandon the root to search for the branches, those who have come to a sublime feast but search for an inferior meal, those who have found the elephant but search for its foot prints, those who do not turn to the lord who offers many welcome benefits, but turn to the slave who gives little and of inferior quality, and so on. There are some who have, in a similar way, abandoned the root of Dharma, becoming haughty from experiencing the mere husks of works, and who also despise those who possess the key points.
Application of concept
Muller (1999: p. 4) discusses Essence-Function (t'i-yung) in relation to "words, thoughts and actions" which are known in Tibetan Buddhism as the Three Gateways:
The most important application of t'i-yung thought, however, is to the human being, where the human mind is seen as "essence," and one's words, thoughts and actions are seen as "function."
Interpenetration and nonduality
'Interpenetration' or 'coalescence' (Wylie: zung 'jug; Sanskrit: yuganaddha; Chinese: 通達) and Essence-Function are mutually informing and fundamentally related doctrinally.
Sung-bae Park (1983: p. 147) identifies essence-function as an East Asian Buddhist strategy to convey nonduality:
Since the t'i-yung or "essence-function" construction is originally used by East Asian Buddhists to show a non-dualistic and non-discriminate nature in their enlightenment experience, it should not exclude any other frameworks such as neng-so or "subject-object" constructions. Nevertheless the essence-function construction must be distinguished from the subject-object construction from a scholastic perspective because the two are completely different from each other in terms of their way of thinking.
Sung-bae Park (2009: p. 11) holds that:
"...the terms mom and momjit are familiar to all Koreans, and have their roots in ancient history. Although I translated them in the introduction as "essence" and "function", a more accurate definition (and the one the Korean populace is more familiar with) is "body" and "the body's functions". The implications of "essence/function" and "body/its functions" are similar, that is, both paradigms are used to point to a nondual relationship between the two concepts. There is a subtle but crucial difference, however, between the two models, "essence/function" and "body/its functions". The term essence/function (which is often translated by East Asian scholars into the Chinese term t'i-yung) has a rather abstract, philosophical tone, connoting an impression of being somewhat removed from the nitty-gritty details of everyday life. My primary interest, however, is in the human being's personal understanding and experience of nonduality."
Chinese Self-Strengthening Movement
This concept was employed by Confucian reformers of the Self-Strengthening Movement at the end of the Qing dynasty's rule in China, in the phrase "Chinese learning for essence, Western learning for application" (Template:Zh). The belief was that China should maintain its own Confucian style of learning to keep the "essence" of society, while at the same time using Western learning for "practical application" in developing its infrastructure and economy.
Origins of the term
The t'i-yung paradigm has roots in the Wei-Chin era of Chinese history, whose predominant intellectual trend was "Unification of the Three Teachings" ideology, i.e., the quest for a theoretical reconciliation among Confucianism, Daoism, and Buddhism. The theory was at first known as pen-mo ("primary-last" or "primary-subordinate"), which developed into t'i-yung. In the initial development of the theory, "thinkers considered one of the three philosophies as 'the primary' or 't'i' and the others as 'the last' or 'yung,' insisting that their own philosophy was superior to the others." However, although the theory was used to arrange the three teachings hierarchically, it also confirmed their inner unity. An especially noteworthy philosopher in this tradition was Wang Pi, who used the pen-mo theory to synthesize Daoism and Confucianism.
- Muller, A. Charles (1995). "The Key Operative Concepts in Korean Buddhist Syncretic Philosophy: Interpenetration (通達) and Essence-Function (體用) in Wŏnhyo, Chinul and Kihwa", Bulletin of Toyo Gakuen University No. 3, March 1995, pp 33-48.
- Sheik, Adam (2008). 體 or Tai. CantoDict v1.3.16. Source:  (accessed: December 20, 2008)
- Sheik, Adam (2008). 用 or Jung. CantoDict v1.3.16. Source:  (accessed: December 20, 2008)
- Muller, A. Charles (2005). Plumbing Essence and Function: The Culmination of the Great Buddhist-Confucian Debate. Source:  (accessed: December 20, 2008)
- Doctor, Thomas H. (trans.) Mipham, Jamgon Ju.(author)(2004). Speech of Delight: Mipham's Commentary of Shantarakshita's Ornament of the Middle Way. Ithaca: Snow Lion Publications. ISBN 1-55939-217-7, p.101x
- Muller, A. Charles (1999). "Essence-Function and Interpenetration: Early Chinese Origins and Manifestations" cited in Bulletin of Toyo Gakuen University, vol. 7 (1999). Source:  (accessed: December 22, 2008) P.4
- Sung-bae Park (1983). Buddhist Faith and Sudden Enlightenment. SUNY series in religious studies. SUNY Press. ISBN 0-87395-673-7, ISBN 978-0-87395-673-4. Source:  (accessed: Friday April 9, 2010), p.147
- Sung-bae Park (2009). One Korean's approach to Buddhism: the mom/momjit paradigm. SUNY series in Korean studies: SUNY Press. ISBN 0-7914-7697-9, ISBN 978-0-7914-7697-0. Source:  (accessed: Saturday May 8, 2010), p.11
- Spence, Jonathan D. The Search for Modern China (New York: Norton, 1999), 225-26. ISBN 0-393-30780-8
- Kim Jong-in (2004), 139.
- Kim Jong-in (2004), 139-146.