阴阳者，一气所分，宜平宜合，忌偏忌离。或为对待，或为流行，有会处，有分处，本相生，亦相克，天地万物无
一可以去之，其理之精微，实非易言者也。考之医籍，或谓阴易亏而阳易亢，务以益阴为先；或谓阴主杀而阳主生，必
以扶阳为重。若此之类，各有至理，而均非定论，何也？以未分常与变耳。试以四时昼夜核之，春夏为阳，秋冬为阴，
两分焉而毫弗参差；夜则为阴，昼则为阳，总计焉而纤无多寡，此阴阳之常也。以大地之变论之，时或亢旱，即阳盛阴
虚之象，必有待于甘霖；时或久阴，即阳衰阴盛之征，是有赖于皎日，此各执其说者，亦有至理也。以人之病论之，水
亏火旺，非清凉无以救其燎原，既不可专以阳为重；气脱神霾，非温热无以消其阴翳，亦不可独以阴为先。非偏执之见，
均非定论乎？
考之先儒，语其大纲，一动一静，互为其根，是为流行；分阴、分阳，两仪立焉，则为定位。言其体用，天以阳生
万物，以阴成万物，惟两故化合而后能遂也。以阳为用则尊阴，以阴为用则尊阳，随时变易，迭相为用也。阳不能独立，
必得阴而后立，故阳以阴为基；阴不能自见，必待阳而后见，故阴以阳为唱。阴阳相生也，体性相须也，是以阳去则阴
竭，阴尽则阳灭。顾阴之为道，利于从阳，不利于抗阳；阳之为性，宜于潜藏，不宜于发泄。若夫阳主进而阴主退，阳
主息而阴主消，进而息者其气强，退而消者其气弱。阳刚温浓，居东南，主春夏，而以作长为事；阴柔严凝，居西北，
主秋冬，而以敛藏为事。作长为生，敛藏为杀，似乎以阳为重，及观天不地不生，夫不妇不成，又谓元不生于元而生于
贞，盖天地之化，不翕聚则不能发散，故不贞则无以为元，而非生生不穷之道也；又不必以阴为轻，则先儒之说未尝偏
轻偏重也。故阴阳得其正，则平若权衡，阴阳失其和，则反如冰炭。自其变者而观之，阳主乎热，阴主乎寒，不可混而
为一；自其不变者而观之，阴气流行即为阳，阳气凝聚即为阴，岂可分而为二。且阴阳互藏其宅，故伤其阳即及其阴，
伤其阴亦即及其阳。阴阳消长无穷，故阳之退便是阴之生，阴之退便是阳之生，《内经》亦曰∶阴阳之道，如环无端是也。
如曰阳能生阴，阴则不能生阳，岂理也耶？且果谷草木，有生于春而成于秋者，亦有生于秋而成于春者，惟独阳则不生，
独阴则不长耳。要之，论其常，则毫厘不可轻重；如其变，则刚柔大有悬殊。所以寒极则冻而死，暑极则热而毙，过则
主乎杀也；晴明物亦荣，雨露物亦茂，和则主乎生也。惟今人之体，偏胜者多，在乎临证者，于向来偏执之说，毋低其
短，善用其长可也。阴阳之理，非一言可以尽之也。
阴阳，是由一气分化而来，应当保持平衡与和谐，忌讳偏颇与分离。它们有时表现为对立关系，有时表现为流动运行；既有交汇之处，也有分离之时；既相互滋生，又相互制约。天地万物没有一样可以脱离阴阳而存在，其道理的精微深奥，实在不是轻易能够说清楚的。
考察医学典籍，有的认为阴容易亏损而阳容易亢盛，务必以补益阴液为先务；有的认为阴主肃杀而阳主生长，必须以扶持阳气为重任。像这样的观点，各自都有深刻的道理，但都不是绝对的定论，为什么呢？因为还没有区分“常”（常态）与“变”（变化）。
试着用四季和昼夜来验证：春夏属于阳，秋冬属于阴，两者分明且毫无差错；夜晚属于阴，白天属于阳，总计起来也毫厘不差，这是阴阳的“常”态。从大地的变化来看，有时出现酷旱，这是阳盛阴虚的现象，必然期待甘霖滋润；有时出现长期阴雨，这是阳衰阴盛的征兆，必然依赖太阳照耀。这些各执一词的说法，也都有其至理。
从人的疾病来看，肾水亏虚、心火旺盛，不用清凉之法无法扑灭燎原之火，因此不可专门重视阳气；气脱神昏，不用温热之法无法消散阴霾，也不可单独重视阴液。这难道不是偏执之见，因而都不是定论吗？
考察古代儒家学者的论述，谈论其大纲：一动一静，互为根本，这就是“流行”；分出阴、分出阳，两仪由此确立，这就是“定位”。谈论其体用：天凭借阳来生成万物，凭借阴来成就万物，只有阴阳二者结合化合后才能顺利发展。以阳为用则尊重阴，以阴为用则尊重阳，随着时间变化而改变，交替发挥作用。阳不能独立存在，必须得到阴才能立足，所以阳以阴为基础；阴不能自行显现，必须等待阳才能显露，所以阴以阳为主导。阴阳相互滋生，体性相互依存，所以阳离去则阴枯竭，阴耗尽则阳灭亡。
然而，阴的道，利于顺从阳，不利于对抗阳；阳的性质，利于潜藏，不利于发泄。至于阳主进取而阴主退守，阳主生息而阴主消减，进取生息的阳气强盛，退守消减的阴气衰弱。阳刚温厚浓郁，居于东南，主宰春夏，以生长发育为事；阴柔严峻凝滞，居于西北，主宰秋冬，以收敛闭藏为事。生长发育即为生，收敛闭藏即为杀，似乎应该重视阳，但看到天无地不生，夫无妇不成，又说“元”不生于“元”而生于“贞”，大概天地的化育，不聚合就不能发散，所以没有“贞”就没有“元”，这就不是生生不息的道理了；也不必轻视阴，那么先儒的说法未曾有偏轻或偏重。
所以，阴阳得其正道，则平衡如同秤杆；阴阳失去和谐，则反差如同冰炭。从其变化的方面观察，阳主热，阴主寒，不可混淆为一；从其不变的方面观察，阴气流行就是阳，阳气凝聚就是阴，岂可分开为二。况且阴阳互相藏匿于对方的宅邸中，所以损伤阳就会波及阴，损伤阴也会波及阳。阴阳消长无穷无尽，所以阳的退去便是阴的生发，阴的退去便是阳的生发，《黄帝内经》也说：阴阳之道，如圆环般没有尽头。如果说阳能生阴，阴却不能生阳，这难道是合理的吗？况且谷物草木，有生于春天而成于秋天的，也有生于秋天而成于春天的，只有独阳不能生，独阴不能长罢了。总之，论其常态，丝毫不可轻重偏废；如其变化，则刚柔大有悬殊。所以寒冷至极则冻死，暑热至极则热毙，过度则主杀伐；晴朗明亮万物繁荣，雨露滋润万物茂盛，和谐则主生长。只是今人的体质，偏胜者居多，关键在于临证施治时，对于向来偏执的说法，不要贬低其短处，善于利用其长处即可。阴阳的道理，不是一句话可以说尽的。
Yin and Yang are differentiated from a single Qi (vital energy). They should be balanced and harmonious, avoiding bias and separation. Sometimes they exist in opposition, sometimes in flow; there are points of convergence and divergence; they mutually generate and restrain each other. Nothing in heaven and earth can exist without them. The subtlety and profundity of their principles are truly not easily expressed.
Examining medical texts, some argue that Yin is prone to deficiency while Yang is prone to hyperactivity, emphasizing the supplementation of Yin as the priority. Others state that Yin governs destruction/salting down while Yang governs growth/life, insisting on supporting Yang as the primary task. Such views, while having profound logic within their own contexts, are not absolute conclusions. Why? Because they fail to distinguish between "Chang" (constancy/normalcy) and "Bian" (change/pathology).
Let us verify this with the four seasons and day and night: Spring and Summer belong to Yang, Autumn and Winter to Yin; these two are distinct without any discrepancy. Night belongs to Yin, Day to Yang; in total, there is no excess or deficit. This represents the constancy of Yin and Yang. Considering changes in the earth: when extreme drought occurs, it is a sign of Yang excess and Yin deficiency, necessitating sweet rain; when prolonged cloudy/rainy weather persists, it is a sign of Yang decline and Yin excess, relying on the bright sun. Those who adhere to specific theories also have valid reasoning.
Regarding human diseases: when Water (Kidney Yin) is deficient and Fire (Heart Yang) is flourishing, only cooling methods can save the raging fire; thus, one cannot exclusively emphasize Yang. When Qi escapes and Spirit is obscured, only warming methods can dissipate the Yin shadow; thus, one cannot exclusively prioritize Yin. Are these not biased views, and therefore not definitive conclusions?
Examining the teachings of ancient Confucian scholars regarding the general outline: movement and stillness serve as roots for each other; this is called "Liu Xing" (flowing circulation). Dividing into Yin and Yang establishes the Two Modes (Liang Yi); this is called "Ding Wei" (fixed positioning). Regarding substance and function: Heaven uses Yang to generate all things and Yin to complete them. Only through the combination of both can development proceed. When Yang is functional, Yin is honored; when Yin is functional, Yang is honored. They change with time and alternate in use. Yang cannot stand alone; it must rely on Yin to establish itself, so Yang takes Yin as its foundation. Yin cannot manifest by itself; it awaits Yang to appear, so Yin follows Yang as its leader. Yin and Yang generate each other; their nature depends on mutual necessity. Therefore, if Yang departs, Yin exhausts; if Yin ends, Yang perishes.
However, the way of Yin favors following Yang and opposes resisting Yang; the nature of Yang favors submergence and opposes emission. Yang governs advancement and Yin retreat; Yang governs growth and Yin wanes. Advancing and growing implies strong Qi; retreating and waning implies weak Qi. Yang is firm, warm, and dense, residing in the southeast, governing Spring and Summer, engaged in production and growth. Yin is soft, strict, and congealed, residing in the northwest, governing Autumn and Winter, engaged in gathering and storing. Production and growth constitute life; gathering and storing constitute death. It seems Yang should be prioritized. Yet, observing that heaven does not produce without earth, nor husband without wife, and that "Yuan" (origin) is born from "Zhen" (steadfastness/endurance), we see that the transformation of heaven and earth requires condensation before dispersion. Without Zhen, there is no Yuan, which would not be the endless path of generation. Thus, Yin should not be considered light. The theories of the ancients did not lean towards bias or weight.
Therefore, when Yin and Yang attain righteousness, they are balanced like a scale; when they lose harmony, they become contrary like ice and charcoal. Viewing from the aspect of change: Yang governs heat, Yin governs cold; they cannot be confused as one. Viewing from the aspect of unchangeability: the flow of Yin Qi is Yang, the condensation of Yang Qi is Yin; how can they be separated into two? Moreover, Yin and Yang hide within each other's dwellings. Thus, injuring Yang affects Yin, and injuring Yin affects Yang. The waxing and waning of Yin and Yang are infinite; the retreat of Yang is the birth of Yin, and the retreat of Yin is the birth of Yang. As stated in the *Nei Jing* (Inner Canon): The Way of Yin and Yang is like a ring without beginning or end. If one says Yang can generate Yin but Yin cannot generate Yang, is this reasonable? Grain, beans, and trees may be born in Spring and mature in Autumn, or born in Autumn and mature in Spring. Only isolated Yang cannot generate, and isolated Yin cannot grow. In summary, discussing constancy, neither should be favored over the other; discussing change, there is a great disparity between rigid and flexible. Extreme cold leads to freezing death; extreme heat leads to burning demise; excess leads to destruction. Clear skies make flora flourish; rain and dew make vegetation lush; harmony leads to life. However, modern people's constitutions often exhibit bias. The key lies in clinical practice: do not dismiss the shortcomings of traditional biased theories, but rather utilize their strengths effectively. The principles of Yin and Yang cannot be fully exhausted in a single statement.