行大论曰∶所谓上下者岁上下见阴阳之所在也。以司天在泉言，见运气类四。）阴阳者，血气之男女也；（阳为气为男，
阴为血为女。左右者，阴阳之道路也；（阳左而升，阴右而降。五营运大论曰∶左右者，诸上见厥阴，左少阴，右太阳之
类。以司天在泉左右间气言，见同前。）水火者，阴阳之征兆也；（征，证也。兆，见也。阴阳不可见，水火即其证而可
见也。）阴阳者，万物之能始也。（能始者，能为变化生成之元始也，能始则能终矣。）故曰∶阴在内，阳之守也；阳在外，
阴之使也。（阴性静，故为阳之守；阳性动，故为阴之使。守者守于中，使者运于外。以法象言，则地守于中，天运于外；
以人伦言，则妻守于中，夫运于外；以气血言，则营守于中，卫运于外。故朱子曰∶阳以阴为基，阴以阳为偶。）
（素问阴阳应象大论）
帝曰∶法阴阳奈何？（法，则也，以辨病之阴阳也。）岐伯曰∶阳胜则身热，腠理闭，喘粗为之 仰，汗不出而热，
齿干，以烦冤腹满死，能冬不能夏。（阳胜者火盛，故身热。阳盛者表实，故腠理闭。阳实于胸，则喘粗不得卧，故为
仰。汗闭于外，则热郁于内，故齿干。阳极则伤阴，故以烦冤腹满死。阴竭者，得冬之助，犹可支持；遇夏之热，不能
耐受矣。冤，郁而乱也。腠音凑。俯， 同。能，耐同。）阴胜则身寒，汗出身常清，数栗而寒，寒则厥，厥则腹满死，
能夏不能冬。（阴胜则阳衰，故身寒。阳衰则表不固，故汗出而身冷。栗，战栗也。厥，厥逆也。阴极者，阳竭于中，故
腹满而死。阳衰者，喜暖恶寒，故能夏不能冬也。脉要精微论亦曰∶阳气有余为身热无汗，阴气有余为多汗身寒。见脉
色二十一。）此阴阳更胜之变，病之形能也。（更胜，迭为胜负也，即阴胜阳病、阳胜阴病之义。形言阴阳之病形，能言
气令之耐受也。）帝曰∶调此二者奈何？（帝以阴阳为病俱能死，故问调和二者之道。）岐伯曰∶能知七损八益，则二者
可调，不知用此，则早衰之节也。（上文言阴阳之变病，此言死生之本原也。七为少阳之数，八为少阴之数。七损者言阳
消之渐，八益者言阴长之由也。夫阴阳者，生杀之本始也。生从乎阳，阳不宜消也；死从乎阴，阴不宜长也。使能知七
损八益之道，而得其消长之几，则阴阳之柄，把握在我，故二者可调，否则未央而衰矣。愚按∶阴阳二气，形莫大乎天
地，明莫着乎日月。虽天地为对待之体，而地在天中，顺天之化；日月为对待之象，而月得日光，赖日以明。此阴阳之
征兆，阴必以阳为主也。故阳长则阴消，阳退则阴进，阳来则物生，阳去则物死，所以阴邪之进退，皆由乎阳气之盛衰
耳。故生气通天等论皆专重阳气，其义可知。又华元化曰∶阳者生之本，阴者死之基。阴常宜损，阳常宜盈。顺阳者多
长生，顺阴者多消灭。中和集曰∶大修行人，分阴未尽则不仙；一切常人，分阳未尽则不死。亦皆以阳气为言。可见死
生之本，全在阳气。故周易三百八十四爻，皆卷卷于扶阳抑阴者，盖恐其自消而剥，自剥而尽，而生道不几乎息矣。观
圣贤虑始之心，相符若此，则本篇损益大义，又安能外乎是哉？一曰∶七损八益者，乃互言阴阳消长之理，欲知所预防
也。如上古天真论云，女得七数，男得八数。使能知七之所以损，则女可预防其损而益自在也；能知八之所以益，则男
可常守其益而损无涉也。阴阳皆有损益，能知所预，则二者何不可调哉？此说亦通。按启玄子注此，谓女为阴七可损，
则海满而血自下，男为阳八宜益，交会而精泄，以用字解为房事。然经血宜调，非可言损，交会精泄，何以言益？故马
氏因之而注为采取之说，岂此论专为男而不为女耶？矧亵狎之训，亦岂神圣正大之意哉？）年四十，而阴气自半也，（阴，
真阴也。四十之后，精气日衰，阴减其半矣。然此言常人之大较，至若彭殇椿菌，禀赋不齐，而太极国中，则又各有其
局象。愚按∶真阴之义，即天一也，即坎水也，丹家谓之元精。道书曰∶涕唾精津汗血液，七般灵物总属阴。又曰∶四
大一身皆属阴，不知何物是阳精？此阳精二字，专指神气为言，谓神必由精而生也。又钟吕集曰∶真气为阳，真水为阴。
阳藏水中，阴藏气中。气主于升，气中有真水；水主于降，水中有真气。真水乃真阴也，真气乃真阳也。凡此之说，皆
深得阴阳之精义。试以人之阳事验之，夫施而泄者，阴之精也，坚而热者，阳之气也，精去而阳痿，则阴之为阳，尤易
见也。此即阴气自半之谓。故本神篇曰∶五脏主藏精者也，不可伤，伤则失守而阴虚，阴虚则无气，无气则死矣。由此
观之，可见真阴者，即真阳之本也。夫水火皆宅于命门，拆之则二，合之则一，造化由此而生，万物由此而出。其在人
身，为性命之根柢，为脏腑之化原。故许叔微云∶补脾不若补肾。诚独见之玄谈，医家之宗旨也。后世有以苦寒为补阴
者，伐阴者也，害莫甚矣，不可不为深察。）起居衰矣。（真阴已半，所以衰也。）年五十，体重，耳目不聪明矣。（肝受
血而能视，足受血而能步，今精血渐衰，故体重而耳目不聪矣。）年六十，阴痿，气大衰，九窍不利，下虚上实，涕泣俱
出矣。（阴痿，阳不举也。阴气内亏，故九窍不利。阴虚则阳无所归而气浮于上，故上实下虚而涕泣俱出。）故曰∶知之
则强，不知则老，（知，谓知损益之道。）故同出而名异耳。（同出者，人生同此阴阳也。而知与不知，则智愚之名异矣。）
智者察同，（愚者察异，智者所见，皆合于道，故察同。愚者闻道则笑，而各是其是，故察异。）愚者不足，智者有余，（愚
者失之，智者得之也。）有余则耳目聪明，身体轻强，老者复壮，壮者益治。（此智者有余之征验。）是以圣人为无为之事，
乐恬 之能，（无为者，天地之道也。恬 者，自然之乐也。老子曰∶道常无为而无不为。又曰∶人法地，地法天，天法
道，道法自然。夫自然而然者，即恬 无为之道也。庄子曰∶天无为以之清，地无为以之宁，故两无为相合，万物皆化。
芒乎芴乎而无从出乎？芴乎芒乎而无有象乎？万物职职，皆从无为殖。故曰天地无为也，而无不为也，人也孰能得无为
哉？二子之言，皆本乎此。能者，如关尹子所谓惟有道之士能为之，亦能能之而不为之之义。）从欲快志于虚无之守，故
寿命无穷，与天地终，此圣人之治身也。（从欲，如孔子之从心所欲也。快志，如庄子之乐全得志也。虚无之守，守无为
之道也。故欲无不从，志无不快，寿命可以无穷，而与天地同其终矣。愚按∶圣人之道，惟圣人能之，人非生知，诚未
能也。然而效法圣贤，则在明哲之所必不容己者，欲得其门，当自养心保身始。故但能于动中藏静，忙里偷闲，致远钩
深，庶乎近矣。观谭景升曰∶明镜无心，无物不照，昊天无心，万象自驰；行师无状，敌不敢欺；至人无虑，元精自归。
能师于无者，无所不之。故镜以察物，物去而镜自镜；心以应事，事去而心自心。此养心之道也。南华经曰∶知道者，
必达于理；达于理者，必明于权，明于权者，不以物害己。故至德者，火弗能热，水弗能溺，寒暑弗能害，禽兽弗能贼，
非谓其薄之也，言察乎安危，宁于祸福，谨于去就，莫之能害也。淮南子曰∶得道之士，内有一定之操，而外能 伸卷
舒，于物推移，故万举而不陷。所以贵圣人者，以其能龙变也，此保身之道也。知此二者，则跻圣功夫，必有能因学而
至者矣。又恬 虚无义，见摄生类二。
《大论》中说：所谓“上下”，是指每年岁运的司天、在泉所对应的阴阳位置。（从司天、在泉的角度来看，这涉及运气学说中的分类，详见运气类第四篇。）
阴阳，是血与气的男女属性；（阳对应气，象征男；阴对应血，象征女。左右，是阴阳运行的道路；（阳从左上升，阴从右下降。《五营运大论》说：所谓左右，是指上面见到厥阴时，左边是少阴，右边是太阳之类。（这是指司天、在泉及其左右间气的关系，详见前文。）
水和火，是阴阳的征兆；（征，即证验。兆，即显现。阴阳本身不可见，但通过水火的表现就可以验证和看见。）
阴阳，是万物变化生成的本源。（能始，是指能够作为变化生成之初始的力量，有了初始就能有终结。）所以说：阴在内，是阳的守持者；阳在外，是阴的役使者。（阴的性质静，所以作为阳的守持者；阳的性质动，所以作为阴的役使者。守持者在内部守护，役使者在外部运作。从法象来说，地守于中，天运于外；从人伦来说，妻守于中，夫运于外；从气血来说，营气守于中，卫气运于外。所以朱熹说：阳以阴为基础，阴以阳为伴侣。）
黄帝问：如何效法阴阳呢？（法，即法则，用来辨别疾病的阴阳属性。）岐伯回答：阳偏胜则身体发热，腠理闭塞，呼吸喘促粗重，不得不仰面呼吸，汗不出而体内热盛，牙齿干燥，因烦闷郁结且腹部胀满而死，这种病能耐受冬天而不能耐受夏天。（阳偏胜则是火盛，所以身体发热。阳盛则体表实，所以腠理闭塞。阳邪实于胸中，导致喘促粗重不能卧，所以要仰面。汗液闭阻于外，热气郁结于内，所以牙齿干燥。阳极则损伤阴气，所以出现烦闷郁结、腹部胀满而死。阴气枯竭的人，得到冬天的帮助，还可以支持；遇到夏天的炎热，就不能耐受。冤，指郁结而乱。腠音凑。俯，通俯。能，通耐。）
阴偏胜则身体寒冷，出汗，身体经常清冷，频繁战栗发冷，冷则四肢厥逆，厥逆则腹部胀满而死，这种病能耐受夏天而不能耐受冬天。（阴偏胜则阳气衰弱，所以身体寒冷。阳气衰弱则体表不固，所以出汗而身体冷。栗，指战栗。厥，指厥逆。阴极则阳气竭于中，所以腹部胀满而死。阳气衰弱的人，喜欢温暖厌恶寒冷，所以能耐受夏天而不能耐受冬天。《脉要精微论》也说：阳气有余表现为身体发热无汗，阴气有余表现为多汗身体寒。详见脉色二十一。）
这是阴阳交替胜负的变化，是疾病的表现和耐受性。（更胜，指轮流胜负，即阴胜阳病、阳胜阴病的含义。形指阴阳的病态表现，能指气候令下的耐受能力。）
黄帝问：调和这两者（阴阳）该怎么做呢？（黄帝认为阴阳失衡都能致死，所以询问调和二者的方法。）岐伯回答：如果能懂得“七损八益”的道理，那么阴阳就可以调和；如果不运用这个道理，就会发生早衰的迹象。（上文讲阴阳变化致病，这里讲生死之本原。七是少阳之数，八是少阴之数。七损是指阳气消减的渐进过程，八益是指阴气增长的缘由。阴阳是生杀的根本。生命源于阳，阳不宜消减；死亡源于阴，阴不宜增长。如果懂得七损八益的道理，掌握其消长的关键，那么阴阳的权柄就把握在自己手中，所以二者可调，否则未老先衰了。我按语：阴阳二气，形体没有比天地更大的，光明没有比日月更显著的。虽然天地是对待之体，但地在天之中，顺应天的化育；日月是对待之象，但月亮依靠日光才明亮。这是阴阳的征兆，阴必须以阳为主导。所以阳长则阴消，阳退则阴进，阳来则物生，阳去则物死，因此阴邪的进退，都取决于阳气的盛衰。所以《生气通天论》等篇章都专门强调阳气，其中的道理可以知道了。另外华佗说：阳是生命的根本，阴是死亡的基础。阴常宜损减，阳常宜充盈。顺从阳的多长生，顺从阴的多消灭。《中和集》说：大修行人，分阴未尽则成不了仙；一切常人，分阳未尽则不会死。也都是以阳气而言。可见生死之本，全在于阳气。所以《周易》三百八十四爻，都致力于扶阳抑阴，大概是担心阳气自行消减，由剥落而至尽绝，从而使生道几乎息灭。看圣贤忧虑起始的心意，如此相符，那么本篇关于损益的大义，又怎能超出这个范围呢？另一种说法：七损八益，是互言阴阳消长的道理，想要知道如何预防。如《上古天真论》说，女子得七数，男子得八数。如果能知道七之所以损，那么女子可以预防其损而益自然存在；如果能知道八之所以益，那么男子可以常守其益而损不涉及。阴阳都有损益，能知道预先防范，那么二者有什么不可调和的呢？这种说法也通。按启玄子注解说，女属阴七可损，则海满而血自下；男属阳八宜益，交会而精泄，将“用”字解释为房事。然而经血宜调，不能说损，交会精泄，怎么能说是益呢？所以马莳沿袭此注解释为采取之说，难道这篇论述专为男性而不为女性吗？况且这种狎昵的解释，哪里符合神圣正大的本意呢？）
人到四十岁，阴气就自然减半了，（阴，指真阴。四十岁以后，精气日渐衰退，阴气减少了一半。但这说的是常人的大概情况，至于彭祖与短命者、椿树与菌类，禀赋不同，而在太极国中，又各有其格局形象。我按语：真阴的含义，就是天一，就是坎水，丹家称为元精。道书说：涕唾精津汗血液，七般灵物总属阴。又说：四大一身皆属阴，不知何物是阳精？这里的阳精二字，专指神气而言，意思是神必须经由精而产生。另外《钟吕集》说：真气为阳，真水为阴。阳藏在水中，阴藏在气中。气主升，气中有真水；水主降，水中有真气。真水乃真阴，真气乃真阳。所有这些说法，都深得阴阳的精义。试着以人的性功能来验证，施泄的是阴精，坚硬发热的是阳气，精去而阳痿，那么阴转化为阳的现象，尤其容易看见。这就是阴气自半的意思。所以《本神篇》说：五脏主藏精，不可损伤，损伤则失守而阴虚，阴虚则无气，无气则死。由此看来，可见真阴是真阳的根本。水火都居住在命门，拆开是两个，合起来是一个，造化由此产生，万物由此而出。在人身，它是性命的根柢，脏腑的化源。所以许叔微说：补脾不如补肾。这确实是独到的玄妙言论，是医家的宗旨。后世有用苦寒药来补阴的，这是伐伤阴气，害处没有比这更大的了，不可不深刻考察。）起居功能衰退了。（真阴已减半，所以衰退。）
人到五十岁，身体沉重，耳目不聪明了。（肝受血滋养才能视物，足受血滋养才能行走，现在精血逐渐衰退，所以身体沉重而耳目不聪明。）
人到六十岁，阴痿（阳痿），气大大衰退，九窍不通利，下虚上实，鼻涕眼泪一起流出。（阴痿，指阳气不能举发。阴气内亏，所以九窍不利。阴虚则阳无所归而气浮于上，所以上实下虚而涕泣俱出。）
所以说：懂得这些就强壮，不懂就会衰老，（知，指懂得损益的道理。）所以同出一源而名称不同罢了。（同出，指人生来都具备同样的阴阳。而知与不知，则智慧与愚笨的名称不同。）
智者观察共同点，（愚者观察差异点，智者所见，都合乎道，所以察同。愚者听到道就嘲笑，各自以为正确，所以察异。）愚者不足，智者有余，（愚者失去它，智者得到它。）有余则耳目聪明，身体轻健，老人恢复强壮，壮年人更加健康。（这是智者有余的征验。）
因此圣人做无为的事，乐于恬淡虚无的能力，（无为，是天地的道。恬淡虚无，是自然的快乐。老子说：道常无为而无不为。又说：人法地，地法天，天法道，道法自然。所谓自然而然，就是恬淡虚无的道。庄子说：天无为所以清，地无为所以宁，所以两无为相合，万物皆化。茫乎忽乎而没有从何处出来？忽乎茫乎而没有形象？万物众多，都从无为繁殖。所以说天地无为，而无不为，人谁能得无为呢？这两位的话，都基于此。能，如关尹子所说只有有道之士能做到，也是能能做到而不为之的意义。）
在虚无的境界中顺从欲望、快适意志，所以寿命无穷，与天地同始终，这是圣人的修身之道。（从欲，如孔子所说的从心所欲。快志，如庄子所说的乐全得志。虚无之守，是坚守无为之道。所以欲望无不顺从，意志无不快适，寿命可以无穷，而与天地同终。我按语：圣人的道，只有圣人能做到，人不是生而知之，确实未能做到。然而效法圣贤，是在明智之人心中必然不容己的事情，想要得其门径，应当从养心保身开始。所以只要在动中藏静，忙里偷闲，致远钩深，差不多就接近了。看谭景升说：明镜无心，无物不照，昊天无心，万象自驰；行师无状，敌不敢欺；至人无虑，元精自归。能效法无的，无所不到。所以镜子用来察物，物去而镜自明；心用来应事，事去而心自定。这是养心的道。《南华经》说：知道的人，必通达于理；通达于理的人，必明于权变，明于权变的人，不以物害己。所以至德之人，火不能烧他，水不能淹他，寒暑不能害他，禽兽不能伤害他，不是说他能抵御这些，而是说他明察安危，安宁于祸福，谨慎于去就，没有什么能伤害他。《淮南子》说：得道之士，内心有一定之操守，而外在能屈伸卷舒，随物推移，所以万举而不陷。之所以尊贵圣人，是因为他能像龙一样变化，这是保身的道。懂得这两点，那么登临圣人的功夫，一定有能通过学问达到的。另外恬淡虚无的含义，见摄生类第二。）
The *Da Lun* (Great Treatise) states: "What is meant by 'upper and lower' refers to the positions of Yin and Yang corresponding to the Si Tian (Heavenly Ruler) and Zai Quan (Earthly Sovereign) of the annual year's movement." (Viewed from the perspective of Si Tian and Zai Quan, this involves the classification of Qi Yun [Qi Movement], see Category 4 of Qi Yun.)
Yin and Yang are the male and female attributes of Blood and Qi; (Yang corresponds to Qi, symbolizing Male; Yin corresponds to Blood, symbolizing Female. Left and Right are the pathways of Yin and Yang; (Yang ascends from the Left, Yin descends from the Right. The *Wu Yun Yun Da Lun* (Great Treatise on the Five Movements and Six Qi) states: "Regarding Left and Right, when Jue Yin is seen above, Shao Yin is on the Left, and Tai Yang is on the Right, and so forth." (This refers to the relationships of Si Tian, Zai Quan, and their intervening Qi on the left and right; see previous text.)
Water and Fire are the omens/signs of Yin and Yang; (Zheng [sign/proof] means evidence. Zhao [omen/appearance] means manifestation. Yin and Yang themselves are invisible, but they can be verified and seen through the manifestations of Water and Fire.)
Yin and Yang are the primordial beginning of the transformation and generation of all things. (Neng Shi [Capable Beginning] refers to the power that serves as the initial source for transformation and generation; having a beginning implies having an end.) Therefore it is said: Yin within is the guardian of Yang; Yang without is the servant of Yin. (Yin’s nature is quiet, thus serving as the guardian of Yang; Yang’s nature is active, thus serving as the servant of Yin. The guardian protects within, while the servant operates without. In terms of natural imagery, Earth guards within while Heaven operates without; in terms of human relations, the wife guards within while the husband operates without; in terms of Qi and Blood, Ying [Nutritive] Qi guards within while Wei [Defensive] Qi operates without. Thus Zhu Xi said: Yang takes Yin as its foundation, and Yin takes Yang as its companion.)
The Yellow Emperor asked: How does one model oneself after Yin and Yang? (Fa [Model/Law] refers to the principles used to distinguish the Yin and Yang of diseases.) Qibo replied: When Yang prevails, the body becomes hot, the Cou Li [interstices/pores] close, breathing becomes asthmatic and coarse, requiring the person to lie with their back raised, sweat does not come out yet heat persists, the teeth become dry, and death ensues due to vexation, oppression, and abdominal fullness. Such patients can endure Winter but cannot endure Summer. (Yang prevailing indicates excessive Fire, hence the body heat. Yang excess leads to exterior solidity, hence closed Cou Li. Yang pathogen solidifies in the chest, causing asthmatic breathing and inability to lie flat, hence the need to recline. Sweat closure on the exterior causes heat stagnation internally, hence dry teeth. Extreme Yang damages Yin, leading to vexation, oppression, and abdominal fullness resulting in death. Those with exhausted Yin can find support in the assistance of Winter but cannot tolerate the heat of Summer. Yuan [oppression] refers to stagnation and chaos. Cou sounds like 'cou'. Fu is synonymous with bending forward. Neng is synonymous with enduring.)
When Yin prevails, the body becomes cold, sweating occurs, the body feels constantly chilly, frequent shivering and chills happen, cold leads to Jue Ni [cold extremities/reversal], and Jue Ni leads to abdominal fullness and death. Such patients can endure Summer but cannot endure Winter. (Yin prevailing indicates Yang deficiency, hence body coldness. Yang deficiency leads to insecure exterior, hence sweating and cold body. Li [shivering] refers to tremors. Jue refers to reversal/cold extremities. Extreme Yin leads to exhaustion of Yang within, causing abdominal fullness and death. Those with deficient Yang prefer warmth and dislike cold, hence they can endure Summer but not Winter. The *Mai Yao Jing Wei Lun* also states: Excess Yang manifests as body heat and no sweat; excess Yin manifests as profuse sweating and body cold. See Pulse Color 21.)
These are the changes of alternating victory and defeat between Yin and Yang, representing the form and tolerance capacity of disease. (Geng Sheng [alternating victory] refers to轮流胜负, meaning Yin excess causing Yang pathology or Yang excess causing Yin pathology. Xing [Form] refers to the pathological manifestations of Yin and Yang; Neng [Capacity/Tolerance] refers to the ability to withstand climatic conditions.)
The Yellow Emperor asked: How should these two (Yin and Yang) be regulated? (Since the Emperor believed that imbalance of either Yin or Yang could lead to death, he asked about the method to harmonize them.) Qibo replied: If one understands the concepts of "Seven Losses and Eight Benefits," then Yin and Yang can be harmonized; if one does not apply this principle, premature aging will occur. (The preceding text discussed disease caused by Yin-Yang changes; here it discusses the root of life and death. Seven is the number of Shao Yang [Lesser Yang]; Eight is the number of Shao Yin [Lesser Yin]. "Seven Losses" refers to the gradual decline of Yang; "Eight Benefits" refers to the growth of Yin. Yin and Yang are the root of life and death. Life stems from Yang, which should not decline; death stems from Yin, which should not grow excessively. If one understands the way of Seven Losses and Eight Benefits and grasps the key of their fluctuation, then the control of Yin and Yang lies in one's own hands, allowing harmony; otherwise, decay sets in before one's time. My commentary: Among Yin and Yang Qi, nothing has a greater form than Heaven and Earth, nothing is more luminous than the Sun and Moon. Although Heaven and Earth are complementary entities, Earth resides within Heaven and follows Heaven's transformations; although Sun and Moon are complementary images, the Moon relies on the Sun's light to shine. This is the omen of Yin and Yang: Yin must take Yang as the master. Thus, when Yang grows, Yin declines; when Yang retreats, Yin advances; when Yang arrives, things are born; when Yang departs, things die. Therefore, the advance and retreat of Yin pathogens depend entirely on the prosperity or decline of Yang Qi. Hence, treatises like *Sheng Qi Tong Tian Lun* focus specifically on Yang Qi, revealing their meaning. Furthermore, Hua Yuanyuan [Hua Tuo] said: Yang is the root of life, Yin is the foundation of death. Yin should often be reduced, Yang should often be filled. Those who follow Yang tend to live long; those who follow Yin tend to perish. *Zhong He Ji* says: Great cultivators cannot become immortals until their share of Yin is exhausted; ordinary people do not die until their share of Yang is exhausted. All these statements emphasize Yang Qi. It is evident that the root of life and death lies entirely in Yang Qi. Therefore, the 384 lines of the *I Ching* are devoted to supporting Yang and suppressing Yin, likely fearing that Yang would self-deplete, undergo peeling [B Gua], and eventually vanish, causing the Way of Life to cease. Observing the sages' concern for beginnings, such consistency shows that the great principles of benefit and loss in this chapter cannot deviate from this. Another interpretation: "Seven Losses and Eight Benefits" mutually explains the principle of Yin-Yang fluctuation, aiming to know how to prevent it. As stated in *Shang Gu Tian Zhen Lun*, women correspond to the number seven, men to eight. If one knows why seven is lost, women can prevent loss and benefit naturally arises; if one knows why eight is benefited, men can maintain benefit and avoid loss. Both Yin and Yang have benefits and losses; knowing how to prepare allows harmony. This interpretation is also valid. According to Qixuanzi's annotation, women belong to Yin-seven which can be lost, leading to fullness of the sea and natural menstruation; men belong to Yang-eight which should be benefited, involving intercourse and essence discharge, interpreting "use" as sexual activity. However, menstrual blood should be regulated, not described as 'loss'; intercourse and essence discharge—how can this be called 'benefit'? Therefore, Ma Shi followed this note and interpreted it as extraction techniques. Is this discussion solely for men and not women? Moreover, such lewd interpretations hardly align with the sacred and upright intent of the classics.)
At forty years of age, Yin Qi naturally halves. (Yin refers to True Yin. After forty, Essence and Qi decline daily, and Yin reduces by half. However, this describes the general rule for ordinary people; regarding Peng Zu [longevity] versus short-lived individuals, or the Oak versus mushrooms, constitutions vary, and within the realm of Taiji, there are different configurations. My commentary: The meaning of True Yin is Tian Yi [One of Heaven], Kan Water, referred to by Daoist alchemists as Yuan Jing [Primal Essence]. Daoist texts say: Tears, saliva, essence, fluids, sweat, blood, and semen—the seven spiritual substances all belong to Yin. Also: The Four Elements constitute the whole body, all belonging to Yin; what is the Yang Essence? Here, "Yang Essence" specifically refers to Shen Qi [Spirit and Qi], implying that Spirit must arise from Essence. Additionally, *Zhong Lü Ji* states: True Qi is Yang, True Water is Yin. Yang hides in Water, Yin hides in Qi. Qi governs ascent, containing True Water within; Water governs descent, containing True Qi within. True Water is True Yin; True Qi is True Yang. All these sayings deeply grasp the essence of Yin and Yang. Test this with human sexual function: Ejaculation is Yin Essence; hardness and heat are Yang Qi. When Essence leaves and impotence occurs, the transformation of Yin into Yang is easily observed. This is what is meant by Yin Qi halving. Thus, *Ben Shen Pian* states: The Five Zang organs store Essence; they must not be injured. Injury leads to loss of control and Yin deficiency; Yin deficiency leads to lack of Qi; lack of Qi leads to death. From this, we see that True Yin is the root of True Yang. Water and Fire reside in the Ming Men [Gate of Life]; separated they are two, united they are one. Creation arises from this, and all things emerge from it. In the human body, it is the root of Life and Nature, and the origin of Zang-Fu transformation. Thus, Xu Shuwei said: Tonifying the Spleen is inferior to tonifying the Kidney. This is indeed a profound insight and the guiding principle of medical practice. Later generations used bitter-cold herbs to tonify Yin, which actually damages Yin; there is no harm greater than this, requiring deep scrutiny.] Living and resting functions decline. (True Yin has halved, hence the decline.)
At fifty years of age, the body becomes heavy, and hearing and vision become unclear. (The Liver receives Blood to enable sight; the Feet receive Blood to enable walking. Now that Essence and Blood gradually decline, the body becomes heavy and hearing/vision diminish.)
At sixty years of age, there is Yin Yi [impotence], Qi greatly declines, the Nine Orifices become obstructed, Lower Deficiency and Upper Excess occur, and tears and mucus flow freely. (Yin Yi refers to the inability of Yang to erect. Internal deficiency of Yin Qi causes obstruction of the Nine Orifices. Yin deficiency leaves Yang without a residence, causing Qi to float upward, resulting in Upper Excess and Lower Deficiency, leading to flowing tears and mucus.)
Therefore it is said: Knowing this brings strength; not knowing it leads to old age. (Zhi [Knowing] refers to understanding the principles of Benefit and Loss.) Thus, they originate from the same source but have different names. (Tong Chu [Same Origin] means humans are born with the same Yin and Yang. But knowing vs. not knowing results in different names of Wisdom and Foolishness.)
The wise observe the commonality, (The foolish observe differences. What the wise see conforms to the Dao, hence observing commonality. The foolish laugh at the Dao and consider only themselves correct, hence observing differences.) The foolish are lacking; the wise are abundant. (The foolish lose it; the wise gain it.) Abundance brings clear hearing and vision, a light and strong body; the elderly regain vigor, and the vigorous become even healthier. (These are the signs of the wise having abundance.)
Therefore, the Sage engages in Wu Wei [Non-action] affairs, finding joy in the capacity for Tian Dan Xu Wu [Tranquility, Emptiness, and Void]. (Wu Wei is the Dao of Heaven and Earth. Tian Dan Xu Wu is the joy of nature. Laozi said: The Dao is always non-action, yet nothing is left undone. Also: Man models himself on Earth, Earth on Heaven, Heaven on Dao, and Dao on Nature. What is natural is precisely the Dao of Tranquility and Non-action. Zhuangzi said: Heaven is clear because of non-action; Earth is peaceful because of non-action. Thus, the combination of two non-actions transforms all things. Vaguely and indistinctly, where do they come from? Indistinctly and vaguely, is there any image? All things are numerous, reproducing from non-action. Thus, Heaven and Earth are non-action, yet accomplish everything. Who among humans can attain non-action? These words of the two sages are based on this. Neng [Ability/Capacity], as Guan Yinzi said, only those with the Dao can achieve it; it also means achieving it without deliberate action.)
Following desires and fulfilling ambitions within the guard of Void, thus extending life infinitely, ending with Heaven and Earth; this is the Sage's method of cultivating the body. (Cong Yu [Following Desire], like Confucius's "following the heart's desire"; Kuai Zhi [Fulfilling Ambition], like Zhuangzi's "joyful fulfillment of will". Shou Xu Wu [Guarding Void] means guarding the Dao of Non-action. Thus, desires are all satisfied, ambitions fulfilled, life can be infinite, and one ends together with Heaven and Earth. My commentary: The Dao of the Sage can only be practiced by Sages; humans are not born with knowledge and truly cannot achieve it. However, emulating sages is an imperative for the wise. To find the door, one must start with nourishing the Heart and preserving the Body. Thus, hiding stillness within movement, stealing leisure amidst busyness, reaching far and probing deep—this is close. Tan Jingsheng said: A bright mirror has no mind, reflecting all things; the vast sky has no mind, letting phenomena run their course; an army without fixed form makes enemies dare not deceive; the Perfect Man has no worries, and Primal Essence returns naturally. One who models themselves on the Formless can go anywhere. Thus, the mirror reflects objects; when objects leave, the mirror remains itself; the Heart responds to affairs; when affairs pass, the Heart remains itself. This is the Dao of nourishing the Heart. *Nanhua Jing* says: One who knows the Dao must understand Reason; one who understands Reason must understand Flexibility; one who understands Flexibility does not let external things harm themselves. Thus, the person of Highest Virtue is not burned by fire, drowned by water, harmed by cold or heat, or attacked by beasts. This does not mean they resist these forces, but that they discern safety and danger, remain tranquil amidst fortune and misfortune, and are cautious in departure and approach, so nothing can harm them. *Huainanzi* says: The person who attains the Dao has a fixed inner integrity but externally can contract and expand, shifting with things, so ten thousand actions do not fail. The reason the Sage is esteemed is their ability to change like a Dragon; this is the Dao of preserving the body. Understanding these two points, the effort to ascend to Sagehood will certainly be achievable through learning. For the meaning of Tranquility, Emptiness, and Void, see Category 2 of Preservation of Health.)