上面，对阴阳已经讨论了很多，对这个问题已经有所了解。现在我们来讨论“阴阳的工作机制”，弄清楚这个以后对理解《伤寒论》的许多问题就会很方便。阴阳是一体两面，一分为二。它的来源与《易》很有关联。孔子在《易·系辞》里说“易有太极，是生两仪”，两仪是什么？两仪就是阴阳，因此，阴阳是从太极来的。太极是《易》系统的一个重要概念，这个概念弄不清楚，中医的很多问题就不容易搞究竟。“太”这个字经常用，像太公太婆、太上皇等，所以，比较容易理解，那么，“极”呢？极这个概念在《说文》叫做“栋”，就是屋脊的意思，是一个最高点。太极显然就是比这个脊更高的地方，比最高的地方还高，这个说法似乎抽象了一点。有没有更具体一些的意义呢？有关极的概念，在最早的一本天文历法书《周髀算经》中有专门的涵义，该经的下卷说：“阴阳之数，日月之法，十九岁为一章。四章为一蔀，七十六岁。二十蔀为一遂，遂千五百二十岁。三遂为一首，首四千五百六十岁。七首为一极，极三万一千九百二十岁。生数皆终，万物复始。天以更元，作纪历。”以上的经文谈到五个重要的概念，就是章、蔀、遂、首、极。章是十九岁，十九这个数就叫做章，这里面就透着一个法度。《素问·至真要大论》讲病机，为什么讲“十九”条？为什么没有加上一个燥？这里面就有一个章法问题，不是随意地加一个可以，减一个也可以。这个章法是很严肃的问题，这是含糊不得的。接下去是四章为一蔀，二十蔀为一遂，三遂为一首，七首为一极。这个“极”是多少年呢？是三万一千九百二十年。也就是说，三万一千九百二十年就叫做一极。那么，到了这个三万一千九百二十年会有什么变化呢？有一个非常大的变化，就是“生数皆终，万物复始”。在这个极点到来的时候，所有的“生数”都终了，在所有的生命结构及生命所需的条件完结之后，又再开始“万物复始”的新的循环。天地宇宙便是在这样一个交替变化中行进。而在每一个新的“极”开始的时候，从天文的角度，都需要重新纪元，重新纪历。这叫做“天以更元，作纪历”。上述这个极的认识大家不要小看了，我们看现代科学发展到今天，它对宇宙有些什么认识呢？一个热寂说，一个大爆炸，一个熵定律，总起来说，宇宙在大爆炸中诞生，诞生形成以后，就按照熵的定律不断演变，直至达到熵的最大值。此时所有有用的能量消耗一空，世界进入死寂，宇宙不可避免地走向死亡。这实际就是“生数皆终”的时候，就是极变到来的时候。是不是这个死亡就这样一直地持续下去，如果真是这样，那史前文明这个概念怎么来？我们这一个文明史怎么产生？所以，这个死亡不会一直地持续下去，它还会变化，还会爆炸，还会有“万物复始”的时候。这个过程，古印度的哲学把它叫做“成、住、坏、空”，宇宙就是在这样一个成、住、坏、空中演进。宇宙形成以后，会有很长一个“住”世的过程，而这个“住”的过程，如果按照熵定律，就是一个熵值不断增大的过程。增大到一定的程度就会产生坏灭，然后不可避免地进入空亡。这个变化过程就叫做一劫，劫后又要复生，又有新劫产生，又有新的成、住、坏、空。从上面这个认识我们可以看到，《周髀算经》的也好，古印度的也好，现代科学的也好，虽然在周期的长短上，在时间单位的意义上会有出入，但究其实质而言，三个认识都是相同的。那我们不禁要问，现代科学有这样先进的理论，有那么多现代化的手段可以利用，它得出这样一个宇宙认识并不奇怪，而古人根本没有这些先进的东西，他们凭什么也得出了同样的认识？这就再一次提醒我们，古人的那套东西真的不可轻视。我们研究古代的东西，不可以用一个“朴素”就搪塞过去，应该知道其中必有奥妙的地方。上面这个成、住、坏、空的周期，古人已经提出来了，就是三万一千九百二十岁，这个就是“极”。在极的终点就会产生很大的变化，这个时候生数已经终了，一切都完蛋了。既然一切完蛋了，怎么还会万物复始呢？在这个节骨眼上，古人认识到，要想在一个极变终了之后还会有另一个极产生，要想使极与极之间能够顺利的转换，就必然有一个比“极”更高的东西，就像孩子生不出孩子，必是母亲方能生出孩子一样。那么，这个“母亲”，这个比“极”更高一辈的东西，就称之为“太极”，太极的概念就这样诞生了。有了太极，在生数终了以后，就可以万物复始，就可以产生新生命，就可以产生新的成、住、坏、空。所以，太极是一个什么东西呢？太极就是这样一个东西，惟有它，宇宙才能不断地循环下去，惟有它，生命才能终而复始。所以，太极就是这样一个如环无端的东西。我们看由北宋周敦颐所传出的太极图，画出的就是一个空空的圆。这样一个圆，它如环无端，正好体现了太极概念的涵义。只可惜后世的许多人误将那个阴阳鱼的画面当作太极图，闹成天大的笑话。有阴阳鱼的这个画面，只能称作两仪图，或者阴阳图，当然，如果连上阴阳图外面这一圈看，叫做太极阴阳图也未尝不可。但，绝不能将阴阳鱼这个画面单称太极图，这如同指子为母，岂不可笑。《系辞》曰：“生生之谓易。”又曰：“易有太极，是生两仪，两仪生四象，四象生八卦，八卦定吉凶，吉凶生大业。”易是什么呢？易就是产生生命的那个东西，那个道理。这个东西，这个道理又是什么呢？就是太极！前几十年，由于人工胰岛素合成成功，于是在科学界产生了一种思潮，认为生命也可以合成。既然蛋白质可以合成，而人又是由蛋白质构成的，那为什么生命不可以合成呢？生命究竟能不能合成？这个问题梁漱溟前辈在他的《人心与人生》中发表过专门的见解：“自然生命靡非始于分化孳息，而人工之造物恒必从构合入手，此世所共见。今曰从构合入手取得生命，吾窃疑其貌似在此。”生命来自单细胞的分裂，就是当今最时髦的无性繁殖，克隆术，也没有违背这个过程。只有分化才能孳息，合成怎么孳息呢？所以，生命不可能由合成产生。只有太极生两仪，两仪生四象，四象生八卦，这个过程不可能倒过来。因此，生命可以合成，在现代找不到根据，在古代也找不到根据。而从这一点我们可以看到，传统与现代并不相违，越是深层的问题越是这样。所以，传统钻得越深，往往对现代的理解就越深刻。当然，反过来也是这样，对现代的问题钻研得越深，有可能对传统的看法就越深刻。所以，传统与现代需要对话，需要高层次的交流。只有这样，东西方文化才有可能真正沟通，才有可能相互获益。而这个对话必须平等，你要高高在上，独称老大，那这个交流就没有办法实现。从“生生之谓易”，从易这门学问对生命的界定，我们应该有这样一个感受，传统的学问绝不容轻视。它不但涉及一般的问题，而且触及科学最深层的问题。生命来自分裂，不来自合成。太极生两仪是分裂过程，两仪生四象也是个分裂过程。在两仪阶段，阴阳初判，这个时候尚未形成生命，等到四象产生了，有了生长收藏，植物类的东西就有可能产生。四象的时候就是二阴二阳，太阳少阳，太阴少阴，或者称少阳老阳，少阴老阴。在这个基础上继续分化，变成三阴三阳，生命就开始形成了。所以，我们要研究生命，特别是研究人的生命，就要特别注意这个三阴三阳。
2.三阴三阳
Above, we have discussed Yin and Yang (Yin-Yang) extensively and gained a certain understanding of this issue. Now let us discuss the "working mechanism of Yin and Yang." Once this is clarified, understanding many issues in *Shanghan Lun* (Treatise on Cold Pathogenic Diseases) will become convenient. Yin and Yang are two sides of one entity, representing a division into two. Their origin is closely related to the *I Ching* (Book of Changes). Confucius said in the *Xi Ci* (Great Commentary) of the *I Ching*: "The I has the Supreme Polarity (Taiji), which generates the Two Modes (Liangyi)." What are the Two Modes? The Two Modes are Yin and Yang; therefore, Yin and Yang derive from the Supreme Polarity. The Supreme Polarity is an important concept in the system of the *I Ching*. If this concept is not clear, many problems in Traditional Chinese Medicine (TCM) are difficult to thoroughly investigate. The character "Tai" (Supreme/Great) is frequently used, such as in Taigong (Grand Duke), Taipo (Grandmother), and Taishang Huang (Retired Emperor), so it is relatively easy to understand. Then, what about "Ji" (Ultimate/Pole)? In the *Shuowen Jiezi*, the concept of "Ji" is defined as "Dong," meaning the ridgepole of a house, representing the highest point. The Supreme Polarity (Taiji) is obviously higher than this ridgepole, higher than the highest point. This description seems somewhat abstract. Is there a more concrete meaning? Regarding the concept of "Ji," the earliest astronomical and calendrical book, *Zhoubi Suanjing* (The Arithmetical Classic of the Gnomon and the Circular Paths of Heaven), has a specific definition. The lower volume states: "The numbers of Yin and Yang, the methods of the sun and moon: nineteen years constitute one Zhang (Chapter). Four Zhang constitute one Bu (Period), totaling seventy-six years. Twenty Bu constitute one Sui (Cycle), totaling one thousand five hundred and twenty years. Three Sui constitute one Shou (Epoch), totaling four thousand five hundred and sixty years. Seven Shou constitute one Ji (Ultimate Cycle), totaling thirty-one thousand nine hundred and twenty years. When the generative numbers end, all things restart. Heaven changes its era name and establishes the calendar." The above scripture mentions five important concepts: Zhang, Bu, Sui, Shou, and Ji. Zhang refers to nineteen years; the number nineteen is called Zhang, implying a certain order or law. In *Suwen: Zhi Zhen Yao Da Lun* (Basic Questions: The Most Essential Truths of the Plain Question), when discussing pathogenesis, why are there nineteen items listed? Why is not one added for Dryness (Zao)? This involves a matter of structural logic (Zhangfa), not something that can be arbitrarily added or subtracted. This structural logic is a serious matter and cannot be vague. Next, four Zhang make one Bu, twenty Bu make one Sui, three Sui make one Shou, and seven Shou make one Ji. How many years is this "Ji"? It is thirty-one thousand nine hundred and twenty years. That is to say, thirty-one thousand nine hundred and twenty years is called one Ji. So, what changes occur at this point of thirty-one thousand nine hundred and twenty years? There is a very significant change: "When the generative numbers end, all things restart." At the arrival of this ultimate cycle, all "generative numbers" come to an end. After all life structures and conditions required for life conclude, a new cycle of "all things restarting" begins. Heaven and Earth proceed through such alternating changes. And at the beginning of every new "Ji," from an astronomical perspective, a new era must be established, and the calendar must be reset. This is called "Heaven changes its era name and establishes the calendar." Do not underestimate the above understanding of "Ji." Look at modern science today; what is its understanding of the universe? There is the Heat Death theory, the Big Bang theory, and the Law of Entropy. Generally speaking, the universe was born in the Big Bang. After its formation, it evolves continuously according to the Law of Entropy until it reaches the maximum value of entropy. At this time, all useful energy is consumed, the world enters a state of dead silence, and the universe inevitably moves toward death. This is actually the moment when "the generative numbers end," i.e., when the ultimate transformation arrives. Will this death continue indefinitely? If so, how do we explain the concept of prehistoric civilizations? How did our current civilization history arise? Therefore, this death will not continue forever; it will change, explode again, and there will be moments of "all things restarting." This process is referred to by ancient Indian philosophy as "Formation, Abiding, Decay, and Emptiness" (Cheng, Zhu, Huai, Kong). The universe evolves through such Formation, Abiding, Decay, and Emptiness. After the universe is formed, there is a long process of "Abiding." According to the Law of Entropy, this "Abiding" process is one of constantly increasing entropy. When it increases to a certain degree, decay and destruction occur, inevitably leading to emptiness. This changing process is called one Kalpa (Jie). After the Kalpa, regeneration occurs, a new Kalpa arises, and there is a new cycle of Formation, Abiding, Decay, and Emptiness. From these perspectives, whether from the *Zhoubi Suanjing*, ancient India, or modern science, although there may be discrepancies in the length of cycles and the significance of time units, essentially, these three understandings are identical. We cannot help but ask: Modern science has such advanced theories and so many modern tools available, so deriving such an understanding of the universe is not surprising. However, the ancients had none of these advanced tools; on what basis did they arrive at the same understanding? This once again reminds us that the wisdom of the ancients should not be underestimated. When studying ancient texts, we cannot dismiss them with the label of "naive"; we must realize that there must be profound mysteries within. The cycle of Formation, Abiding, Decay, and Emptiness mentioned above was proposed by the ancients as thirty-one thousand nine hundred and twenty years; this is the "Ji." At the endpoint of the Ji, major changes occur. At this time, the generative numbers have ended, and everything is finished. Since everything is finished, how can "all things restart"? At this critical juncture, the ancients realized that for another Ji to arise after the end of one ultimate transformation, and for a smooth transition between Ji and Ji, there must be something higher than the "Ji." Just as a child cannot give birth to a child, only a mother can give birth to a child. Thus, this "mother," this entity one generation higher than the "Ji," is called the "Supreme Polarity" (Taiji). The concept of Taiji was thus born. With Taiji, after the generative numbers end, all things can restart, new life can be generated, and new cycles of Formation, Abiding, Decay, and Emptiness can emerge. So, what is Taiji? Taiji is precisely this entity. Only through it can the universe continue its endless circulation; only through it can life end and begin anew. Therefore, Taiji is like a ring without beginning or end. Consider the Diagram of the Supreme Polarity transmitted by Zhou Dunyi of the Northern Song Dynasty, which depicts an empty circle. Such a circle, having no beginning or end, perfectly embodies the meaning of the concept of Taiji. Unfortunately, many later people mistakenly took the image of the Yin-Yang fish as the Taiji diagram, causing a great joke. The image with the Yin-Yang fish can only be called the Diagram of the Two Modes (Liangyi) or the Yin-Yang Diagram. Of course, if viewed together with the outer circle surrounding the Yin-Yang diagram, it might be called the Taiji Yin-Yang Diagram. However, the image of the Yin-Yang fish alone must never be called the Taiji Diagram. This is like pointing to a son and calling him the mother—how ridiculous! The *Xi Ci* says: "Generating life is called Yi (Change)." It also says: "The I has the Supreme Polarity, which generates the Two Modes; the Two Modes generate the Four Images; the Four Images generate the Eight Trigrams; the Eight Trigrams determine good fortune and misfortune; good fortune and misfortune generate great undertakings." What is Yi? Yi is that which generates life, that principle. What is this thing, this principle? It is the Supreme Polarity! Decades ago, following the successful synthesis of artificial insulin, a trend emerged in the scientific community believing that life could also be synthesized. Since proteins can be synthesized, and humans are composed of proteins, why can't life be synthesized? Can life truly be synthesized? Mr. Liang Shuming addressed this question specifically in his work *Ren Xin Yu Ren Sheng* (Human Heart and Human Life): "Natural life invariably begins with differentiation and reproduction, while artificial creation invariably starts from combination. This is universally observed. Today, claiming to obtain life starting from combination, I suspect its appearance is merely superficial." Life originates from the division of single cells. Even the currently fashionable asexual reproduction, cloning technology, does not violate this process. Only through differentiation can reproduction occur; how can combination reproduce? Therefore, life cannot be produced by synthesis. The process where the Supreme Polarity generates the Two Modes, the Two Modes generate the Four Images, and the Four Images generate the Eight Trigrams, cannot be reversed. Therefore, the idea that life can be synthesized finds no basis in modern science, nor does it find any basis in ancient wisdom. From this point, we can see that tradition and modernity are not contradictory; this is especially true for deeper issues. Thus, the deeper one delves into tradition, the more profound one's understanding of modernity often becomes. Conversely, the deeper one investigates modern issues, the more profound one's view of tradition may become. Therefore, tradition and modernity need dialogue and high-level exchange. Only in this way can Eastern and Western cultures truly communicate and benefit each other. This dialogue must be equal; if one stands arrogantly above, claiming sole superiority, such exchange cannot be realized. From "Generating life is called Yi" and from the definition of life in the study of Yi, we should have the feeling that traditional scholarship must absolutely not be underestimated. It not only addresses general issues but touches upon the deepest problems of science. Life comes from division, not from synthesis. The Supreme Polarity generating the Two Modes is a process of division; the Two Modes generating the Four Images is also a process of division. At the stage of the Two Modes, Yin and Yang are initially distinguished; at this time, life has not yet formed. When the Four Images are generated, possessing growth, flourishing, harvesting, and storing, plant-like things may potentially emerge. The Four Images correspond to two Yin and two Yang: Taiyang (Greater Yang), Shaoyang (Lesser Yang), Taiyin (Greater Yin), Shaoyin (Lesser Yin), or alternatively referred to as Shaoyang/Laoyang (Old Yang) and Shaoyin/Laoyin (Old Yin). Continuing to differentiate from this foundation leads to the Three Yin and Three Yang, at which point life begins to form. Therefore, if we wish to study life, particularly human life, we must pay special attention to the Three Yin and Three Yang.
2. Three Yin and Three Yang