论曰。天地者。阴阳之本也。阴阳者。天地之道也。万物之纲纪。变化之父母。生杀之本始。神明之府也。
故阴阳不测谓之神。神用无方谓之圣。倘不知此。谓天自运乎。地自处乎。岂足以语造化之全功哉。大哉干元。
万物资始。至哉坤元。万物资生。所以天为阳。地为阴。水为阴。火为阳。阴阳者。男女之血气。水火者。
阴阳之征兆。惟水火既济。血气变革。然后刚柔有体。而形质立焉。经所谓天复地载。万物悉备。莫贵乎人。
人禀天地之气生。四时之法成。故人生于地。悬命于天。人生有形。不离阴阳。盖人居天之下地之上气交之中。
不明阴阳而望延年。未之有也。何则。苍天之气。不得无常也。气之不袭。是谓非常。非常则变矣。王注曰。
且苍天布气。尚不越于五行。人在气中。岂不应于天道。左传曰。违天不祥。系辞云。一阴一阳之谓道。老
子曰。万物负阴而抱阳。故偏阴偏阳谓之疾。夫言一身之中。外为阳。内为阴。气为阳。血为阴。背为阳。
腹为阴。腑为阳。脏为阴。肝心脾肺肾五脏皆为阴。胃大肠小肠膀胱三焦六腑皆为阳。盖阳中有阴。阴中有阳。
岂偏枯而为道哉。经所谓治心病者。必求其本。是明阴阳之大体。水火之高下。盛衰之补泻。远近之大小。
阴阳之变通。夫如是惟达道人可知也。
It is stated: Heaven and Earth are the root of Yin and Yang. Yin and Yang are the Way of Heaven and Earth, the general principles of all things, the parents of change, the beginning and end of life and death, and the residence of spiritual transformation.
Therefore, the unpredictability of Yin and Yang is called "Shen" (Spirit/Spiritual), and the application of Shen without fixed methods is called "Sheng" (Sage). If one does not understand this, and assumes that Heaven moves by itself and Earth rests by itself, how can one speak of the complete efficacy of Creation? Great is the Primal Power of Qian (Heaven); all things derive their beginning from it. Supreme is the Primal Power of Kun (Earth); all things derive their growth from it. Thus, Heaven is Yang, Earth is Yin; Water is Yin, Fire is Yang. Yin and Yang correspond to the blood and Qi of men and women; Water and Fire are the omens/signs of Yin and Yang. Only when Water and Fire achieve mutual interaction (Ji Ji) and blood and Qi undergo transformation, can rigid and soft elements take form, and thus physical substance be established. The Classics state: Heaven covers and Earth bears; all things are fully prepared, with nothing more precious than humanity. Humans are born by inheriting the Qi of Heaven and Earth, and mature by following the laws of the Four Seasons. Therefore, humans are born on Earth, but their life is suspended from Heaven. Humans possess form and cannot depart from Yin and Yang. Generally, humans reside below Heaven, above Earth, in the midst of the intersection of Qi. To hope for longevity without understanding Yin and Yang has never been known to happen. Why is this? The climate of the Blue Heaven cannot be without constancy. If the Qi does not follow its regular succession, it is called abnormal. Abnormality leads to alteration. Wang Bing's commentary states: Even the distribution of Qi by Heaven does not exceed the Five Phases. Since humans exist within the Qi, should they not correspond to the Way of Heaven? The Zuo Zhuan states: Violating Heaven brings no auspiciousness. The Commentary on the Appended Phrases says: One Yin and one Yang is called the Dao. Laozi states: All things carry Yin and embrace Yang. Therefore, deviation towards Yin or deviation towards Yang is termed disease. Regarding the human body: the exterior is Yang, the interior is Yin; Qi is Yang, Blood is Yin; the back is Yang, the abdomen is Yin; the Fu organs are Yang, the Zang organs are Yin. The five Zang organs—Liver, Heart, Spleen, Lung, Kidney—are all Yin. The six Fu organs—Stomach, Large Intestine, Small Intestine, Bladder, Sanjiao (Triple Burner)—are all Yang. Generally, there is Yin within Yang, and Yang within Yin. How could a partial skew constitute the Dao? The Classics state: When treating heart diseases, one must seek the root. This clearly elucidates the general framework of Yin and Yang, the high and low positions of Water and Fire, the tonification and sedation for excess and deficiency, the relationships of distance and proximity, size and magnitude, and the flexibility and adaptation of Yin and Yang. Only those who have attained profound understanding can know such matters.