人之有生，初生两肾，渐及脏腑，五脏内备，各得其职，五象外布，而成五官，为
筋、为骨、为肌肉皮毛、为耳目口鼻躯设形骸，然究其源，皆此一点精气，神递变而凝
成之也。犹之混沌未分，纯一水也，水之凝成处，为土、为石、为金，皆此一气化源，
故水为万物之源，土为万物之母。然无阳则阴无以生，故生人之本，火在水之先也；无
阴则阳无以化，故生人之本，水济火之次也。《经》所谓∶阳生阴长，而火更为万物
之父者此耳。是以维持一身，长养百骸者，脏腑之精气主之。充足脏腑，固注元气者，
两肾主之。其为两肾之用，生生不尽，上奉无穷者，惟此真阴真阳二气而已，二气充
足，其人多寿∶二气衰弱，其人多夭；二气
和平，其人无病；二气偏胜，其人多病；二气绝灭，其人则死，可见真阴真阳者，所以
为先天之本，后天之命。两肾之根，疾病安危，皆在乎此。学人仅知本气，而不知乘乎
内虚；仅知治邪，而不知调其本气∶仅知外袭，而不知究其脏腑；仅知脏腑，而不知根
乎两肾；即知两肾，而不知由乎二气，是尚未知求本者也。何况仅以躯壳为事，头疼救
头，脚疼救脚，而不知头脚之根，在脏腑者，何以掌司命之任，而体好生之道欤？真
由缘木求鱼者也。故先哲曰∶见痰休治痰，见血休治血，无汗不发汗，有热莫攻热，喘
生毋耗气，遗精勿涩泄。明得个中趣，方是医中杰，真求本之谓也。
人之所以能够生存，最初形成的是两肾，逐渐发展遍及五脏六腑。五脏在体内完备，各自履行其职能；五象（指心、肝、脾、肺、肾对应的外在表现）向外分布，从而形成五官。身体表现为筋、骨、肌肉、皮毛，耳目口鼻及躯干构成了形体骸骨。然而究其根源，这一切都是由这一点点精气，通过神的递变凝聚而成的。
这就好比天地混沌未分之时，纯粹是一团水。水凝结的地方，变成了土、石、金等物质，这都是由同一气化源头所化生。所以水是万物的源头，土是万物的母体。然而没有阳则阴无法生成，所以人类生命的根本，火在水之先；没有阴则阳无法化生，所以人类生命的根本，水济助火的次序在后。《内经》所说的“阳生阴长”，以及火更是万物之父，就是这个道理。
因此，维持一身、长养百骸的，是由脏腑的精气来主导的。使脏腑充足、固摄元气的，是由两肾来主导的。两肾发挥作用，生生不息、上奉无穷尽的，只有真阴和真阳二气罢了。这两气充足，人就能长寿；这两气衰弱，人就容易夭折；这两气平和，人就没有疾病；这两气偏胜（一方过强），人就容易生病；这两气绝灭，人就会死亡。由此可见，真阴和真阳是先天之本，也是后天生命的关键。两肾的根本，以及疾病的安危，都取决于此。
学习中医的人，如果只知道本气（正气），却不知道病邪乘虚而入的道理；只知道治疗邪气，却不知道调理本气；只知道外感侵袭，却不知道探究脏腑内部；只知道关注脏腑，却不知道根源在于两肾；即使知道了两肾，却不知道关键在于真阴真阳二气，这都算是还没有懂得探求根本的方法。更何况只把身体躯壳当作一回事，头痛医头，脚痛医脚，却不知道头和脚的根源在于脏腑，这样的人怎么能担当起掌管生命重任、体现好生之德的呢？这真是缘木求鱼啊。
所以先哲说：见到痰不要只治痰，见到血不要只治血，无汗时不要强行发汗，有热时不要一味攻热，喘症产生时不要耗损正气，遗精时不要单纯使用涩泄之法。明白了其中的奥妙，才是医学中的杰出人才，这才是真正的探求根本。
Human life begins with the initial formation of the two Kidneys, gradually extending to the Zang-Fu organs. The five Zang organs are complete internally, each fulfilling its function; the five manifestations (referring to the external expressions corresponding to the Heart, Liver, Spleen, Lung, and Kidney) distribute externally, thereby forming the five sense organs. The body manifests as sinews, bones, muscles, skin, and hair, while the eyes, ears, mouth, nose, and trunk constitute the physical form. However, investigating their source, all of these are condensed from a tiny amount of Essence-Qi through the progressive transformation of Spirit.
This is akin to the state before heaven and earth were differentiated, which was purely Water. Where Water condenses, it becomes Earth, Stone, and Metal; all originate from the same Qi-transforming source. Therefore, Water is the source of all things, and Earth is the mother of all things. Yet, without Yang, Yin cannot be generated; thus, in human generation, Fire precedes Water. Without Yin, Yang cannot transform; thus, in human generation, Water assisting Fire follows subsequently. This is what the *Classic* (*Huangdi Neijing*) refers to when stating "Yang generates, Yin grows," and that Fire is the father of all things.
Therefore, what maintains the entire body and nourishes the hundred bones is governed by the Essence-Qi of the Zang-Fu organs. What enriches the Zang-Fu organs and secures the Primordial Qi is governed by the two Kidneys. The function of the two Kidneys, generating endlessly and offering boundlessly upwards, relies solely on the True Yin and True Yang Qi. When these two Qi are sufficient, one lives long; when they are weak, one dies young; when they are harmonious, one is free from disease; when they are imbalanced (one prevailing over the other), one falls ill frequently; when they are extinguished, one dies. Thus, it is evident that True Yin and True Yang serve as the root of the Pre-Heaven constitution and the destiny of the Post-Heaven life. The root of the two Kidneys, and the safety or peril of diseases, all depend于此 (hereon).
Practitioners who only know the Root Qi but fail to understand how pathogens exploit internal deficiency; who only know how to treat pathogens but fail to regulate the Root Qi; who only know about external invasions but fail to investigate the Zang-Fu organs; who only know the Zang-Fu organs but fail to trace them back to the two Kidneys; and even those who know the two Kidneys but fail to recognize their reliance on the two Qi (True Yin and True Yang)—all of these have not yet learned to seek the root. How much more so for those who merely deal with the physical shell, treating the head when it hurts and the foot when it hurts, without knowing that the root of the head and feet lies within the Zang-Fu organs? Such individuals cannot assume the responsibility of managing life or embody the Way of cherishing life. This is indeed like climbing a tree to catch fish.
Thus, the sages of old said: "When seeing phlegm, do not merely treat phlegm; when seeing blood, do not merely treat blood; when there is no sweat, do not forcibly induce sweating; when there is heat, do not aggressively clear heat; when wheezing arises, do not consume Qi; when seminal emission occurs, do not merely use astringents." To understand the profound interest within these principles is to be an outstanding physician; this is truly what is meant by seeking the root.