张景岳《三焦胞络命门辨》云，“命门为阳气之根，故随三焦相火之脉，同见于右尺。”按命门居两肾中间，即人身
之太极，乃阴阳之根底，既为阳气之根，亦为阴气之根。景岳《真阴论》云∶“命门之火，谓之元气，命门之水，谓之元
精。”论理并无偏倚，及至论及脉位，则但将右尺以候阳气之根，将谓左尺不可以候阴气之根乎？将谓阴气之根，亦于右
尺诊之乎？将谓命门但候元气，不必候其元精乎？此景岳之偏于温补，其误即在于此，所谓差之毫厘者也。按命门原气，
禀于有生之初，得父母之两神相合而化形，如露珠之一滴升于丹鼎之上，以为生身立命之根，天地、阴阳、五行之精，
亦即妙合，于是五脏六腑、四肢百骸由此而生，不可以言水火，并不可以言精气，乃精、气、神三家会合，而始成此一
点，莫可名言，而曰命门，指人身有生之根，天之所命而名之。左氏曰∶民受天地之中以生，所谓命也，此之谓欤。命
门一点，藏于两肾中间，以营运阴阳之气，全借肾中阳气、阴精以为之养。在有生以前，则精气生长于命门，在有生以
后，则精气之生于命门者，命门反须精气以养焉。精气不足，犹可峻补以救之，至精气大伤，而命门生气之原绝，则非
补精气之所能挽回，故言至水火精气，已属肾阴、肾阳，而非命门矣。夫命门为生气之原，非特右尺不能候，即两尺亦
不能候，且六部俱不能候，是当以《难经》为断也。《八难》曰“诸十二经脉者，皆系于生气之原。所谓生气之原者，
谓十二经之根本也，谓肾间动气也。此五藏六腑之本，十二经脉之根，呼吸之门，三焦之原，一名守邪之神。故气者，
人之根本也，根绝则茎叶枯矣。寸口脉平而死者，生气独绝于内也。”独是《一难》独取寸口以决死生，而《八难》言寸
口脉平亦死，是何其自相悖谬乎？盖寸口为脉之大会，可决死生，乃谷气之变见，后天有形之可脉也；生气之原绝，则
寸口脉平犹死，乃元神之聚散，先天无形之不可脉也。然则命门之绝，将不可脉之而已乎？《经》曰∶“望而知之谓之神”，
在医者之以神照神，乃神圣之能事，诚非下士之所能窥测，而以右尺为诊，则固知其非也。
张景岳在《三焦胞络命门辨》中说：“命门是阳气的根本，所以随着三焦相火的经脉，一同出现在右尺脉。”按照这种说法，命门位于两肾中间，就是人身体的太极，是阴阳的根本。既然它是阳气的根本，也是阴气的根本。张景岳在《真阴论》中说：“命门的火，叫做元气；命门的水，叫做元精。”从理论道理上讲并没有偏颇，但等到论述到脉位时，却只把右尺脉用来候察阳气的根本，难道认为左尺脉不可以候察阴气的根本吗？难道认为阴气的根本，也要在右尺脉诊察吗？难道认为命门只候察元气，不必候察它的元精吗？这是张景岳偏向于温补疗法，他的错误就在这里，这就是所谓的差之毫厘谬以千里。
按：命门的原气，禀受于生命形成之初，得到父母的两股精气结合而化生形体，就像露珠的一滴升腾到丹鼎之上，作为立身立命的根本。天地、阴阳、五行的精华，也在此妙合，于是五脏六腑、四肢百骸由此而生。这里不能简单地说水火，也不能仅仅说精气，而是精、气、神三家会合，才形成了这一点，无法用言语形容，称之为命门，是指人身生命的根源，上天所赋予而命名的。左丘明说：“百姓承受天地的中和之气而生，这就叫‘命’”，说的就是这个意思吧。命门这一点，藏在两肾中间，用来营运阴阳之气，完全依靠肾中的阳气、阴精来滋养它。在有生命之前，精气在命门中生长；在有生命之后，在命门中产生的精气，命门反而需要精气来滋养它。如果精气不足，还可以用峻猛的补药来救治；至于精气大伤，导致命门生气之源断绝，那就不是补充精气所能挽回的了，所以说到了水火精气，已经属于肾阴、肾阳的范畴，而不是命门了。
夫命门是生气的源头，不仅右尺脉不能候察，就连两尺脉也不能候察，甚至六部脉都不能候察，这应当以《难经》的说法为准。《难经·八难》说：“所有的十二经脉，都系连于生气的源头。所谓生气的源头，就是十二经的根本，称为肾间动气。这是五脏六腑的本源，十二经脉的根蒂，呼吸的门户，三焦的源头，又名守邪之神。所以气，是人的根本，根绝了那么茎叶就会枯死。寸口脉象平和却死了的人，是因为生气独自在体内断绝了。”唯独《难经·一难》主张独取寸口脉来判断生死，而《八难》却说寸口脉象平和也会死，这岂不是自相矛盾吗？大概因为寸口是脉会的部位，可以判断生死，那是谷气变化显现出来的，是有形的后天可诊之脉；而生气的源头断绝，那么即使寸口脉象平和也会死，那是元神聚散的表现，是无形的先天不可诊之脉。
然而，那么命门断绝，就完全不可通过脉诊了吗？《内经》说：“望而知病者叫做神”，在于医者以精神去照察患者的精神，这是神圣的能力，确实不是下等医士所能窥测的。但如果仅凭右尺脉来诊察，那固然知道是错误的。
Zhang Jingyue stated in *Differentiation of the Sanjiao, Pericardium Collateral, and Mingmen*: "The Mingmen (Gate of Life) is the root of Yang Qi, thus it follows the meridians of the Minister Fire of the Sanjiao and appears together at the Right Chi pulse position." According to this view, the Mingmen resides between the two Kidneys, representing the Taiji of the human body, and serves as the foundation of Yin and Yang. Since it is the root of Yang Qi, it is also the root of Yin Qi. Zhang Jingyue wrote in *Discussion on True Yin*: "The fire of the Mingmen is called Yuan Qi (Original Qi); the water of the Mingmen is called Yuan Jing (Original Essence)." Theoretically, there is no bias; however, when discussing pulse positions, he only assigns the Right Chi to monitor the root of Yang Qi. Does this imply that the Left Chi cannot monitor the root of Yin Qi? Or does it imply that the root of Yin Qi should also be diagnosed at the Right Chi? Or does it imply that the Mingmen only monitors Yuan Qi and need not monitor its Yuan Jing? This reflects Zhang Jingyue's bias toward warm-tonifying methods, and his error lies precisely here, which is what is meant by "a miss is as good as a mile."
According to analysis: The Original Qi of the Mingmen is endowed at the beginning of life, formed through the union of the essence and spirit of both parents. It is like a drop of dew rising above the cinnabar furnace, serving as the root for establishing life. The essence of Heaven and Earth, Yin and Yang, and the Five Elements also miraculously combine here, giving rise to the Zang-Fu organs of the five zang and six fu, and the four limbs and hundred bones. Here, one cannot simply speak of Water and Fire, nor merely of Essence and Qi; rather, it is the convergence of Essence, Qi, and Spirit that forms this single point, which is ineffable and thus named Mingmen, referring to the root of human life, bestowed by Heaven. Zuo Qiuming said: "People are born receiving the central energy of Heaven and Earth, which is called 'Ming' (Life/Fate)," referring to this concept. This single point of the Mingmen is hidden between the two Kidneys, operating the Qi of Yin and Yang, relying entirely on the Yang Qi and Yin Essence within the Kidneys for nourishment. Before birth, Essence and Qi grow within the Mingmen; after birth, the Essence and Qi generated by the Mingmen require the Mingmen itself to be nourished by Essence and Qi. If Essence and Qi are insufficient, they can still be rescued with potent tonification; but if Essence and Qi are severely damaged, leading to the severance of the source of vital Qi in the Mingmen, it cannot be reversed by merely supplementing Essence and Qi. Therefore, speaking of Water, Fire, Essence, and Qi belongs to the realm of Kidney Yin and Kidney Yang, not the Mingmen.
Since the Mingmen is the source of vital Qi, it cannot be monitored by the Right Chi alone, nor by both Chi positions, nor even by any of the six pulse positions. Thus, judgment should be based on the *Nan Jing* (Classic of Difficult Issues). *Nan Jing, Chapter 8* states: "All twelve primary meridians are connected to the source of vital Qi. This source of vital Qi is the root of the twelve meridians, known as the Moving Qi between the Kidneys. This is the root of the five zang and six fu organs, the root of the twelve meridians, the gate of respiration, and the source of the Sanjiao, also called the Deity that guards against pathogenic factors. Therefore, Qi is the root of human life; if the root is severed, the stems and leaves will wither. In cases where the Cun Kou pulse is peaceful yet death occurs, it is because the vital Qi has been uniquely severed internally." Yet, *Nan Jing, Chapter 1* advocates taking only the Cun Kou pulse to determine life and death, while *Chapter 8* states that even a peaceful Cun Kou pulse leads to death. Is this not self-contradictory? The reason is that the Cun Kou is the gathering place of pulses and can determine life and death based on the manifestation of Grain Qi (Gu Qi), which is a tangible, postnatal pulse. However, when the source of vital Qi is severed, even a peaceful Cun Kou pulse results in death, reflecting the aggregation and dispersion of the Primordial Spirit, which is intangible and pre-natal, and thus beyond the scope of pulse diagnosis.
Then, does the severance of the Mingmen mean it is completely undiagnosable by pulse? The *Jing* (Classics) state: "To know [the disease] through observation is called Divine." This relies on the physician using their spirit to illuminate the patient's spirit, which is a divine capability, certainly not something inferior physicians can fathom. To diagnose solely via the Right Chi is undoubtedly incorrect.