尝读《难经》、叔和、启玄、诸大贤三焦论，皆谓有名无形。又读《灵枢经》曰∶密理浓皮者，三焦浓；粗理薄皮者，
三焦薄。勇士者，三焦理横；怯士者，三焦理纵。则似乎有形矣。及观李士材曰∶肌肉之内，藏腑之外为三焦；亦无形
也。而士材又以无形为误，而以《灵枢》之浓薄、纵横，如雾、如沤、如渎，以征其形。则三焦究属有形耶，无形耶？
谨赘一言以辨之。夫三焦者，即胸、膈、腹内、三空处也，诸大贤皆谓有名无形者，所以别其不同于他藏他腑之自具一
形耳，非曰无形即无其处，正欲指空处，故曰无形也。《灵枢》谓浓薄纵横者，即借胸膈腹之腔子里面为言，非另具一形
而为浓薄、纵横也。《经》又曰∶如雾、如沤、如渎，而中焦又有作如沥者，盖即指胸、膈、腹内空处之水气为喻。如果
有形，则雾乃气聚，有时而散，沤为水泡，时起时没，沥是余滴，可有可无，皆无常形，岂可比之上中二焦乎？至于下
焦如渎者，亦不过以沟渎中水道，比下焦之水道，非以沟渎之壳子相比较也。即士材所谓肌肉之内，藏腑之外，虽有其
处，原无其形，何反以无形为误，岂其意以既有其处，即不得谓之无形耶？然处与形不同，有其处，《内经》所以云云；
无其形，诸贤所以定论。先圣后贤，言似异而旨实同也。惟陈无择言有形如脂膜，疑未妥协，盖脂膜乃身中原有之物，
三焦之形如之，则又一层假脂膜也，假脂膜与真脂膜，其何以辨哉？故敢谓其未妥。
我曾阅读《难经》、王叔和（晋代医家）、启玄子（唐代医家）等各位大贤关于三焦的论述，他们都认为三焦“有名而无形”。我又读到《灵枢经》中说：皮肤纹理细密、皮厚的，三焦就厚；皮肤纹理粗糙、皮薄的，三焦就薄。勇敢的人，三焦的纹理是横向的；怯懦的人，三焦的纹理是纵向的。这看起来似乎是有形的了。等到看到李士材（明代医家李中梓的字）说：肌肉之内，脏腑之外，就是三焦；这也是无形的。然而李士材又认为“无形”的说法是错误的，他引用《灵枢经》中关于三焦厚薄、纵横的描述，以及如雾、如沤、如渎的比喻，来证明三焦是有形的。那么，三焦究竟是有形还是无形呢？我谨补充一句话来辨析这个问题。所谓三焦，就是胸、膈、腹内的三个空腔部位。各位大贤都说它“有名而无形”，是为了区别于其他脏器和腑器各自具有具体的形态，并不是说没有形体就没有其所在部位，正是为了指出这些空腔部位，所以才说它是无形的。《灵枢经》所说的厚薄、纵横，是借胸、膈、腹这些腔体内部的情况来说明，并非另外具有一种具体的形态来表现为厚薄或纵横。《内经》又说：上焦如雾，中焦如沤，下焦如渎，而中焦又有说是如沥（滴漏）的，这大概是指胸、膈、腹内空腔中的水气作为比喻。如果三焦是有具体形体的，那么雾是气聚集，有时消散；沤是水泡，时起时灭；沥是剩余的液滴，可有可无，它们都没有固定的形状，怎么能用来比拟上焦和中焦呢？至于下焦如渎，也不过是用沟渠中的水道，来比喻下焦的水道功能，而不是用沟渠的壳子来进行比较。就像李士材所说的“肌肉之内，脏腑之外”，虽然有其存在的部位，原本并没有具体的形体，为什么反而认为“无形”是错误的？难道他的意思是既然有了部位，就不能称之为无形吗？然而，“部位”与“形体”是不同的，有它的部位，《内经》才那样说；没有具体的形体，各位贤者才下定论。先圣和后贤的话看似不同，但宗旨其实是相同的。只有陈无择（宋代医家）说三焦有形，像脂膜一样，我怀疑这种说法并不妥当。因为脂膜是人体中原有的实物，如果三焦的形体像脂膜，那就又多了一层假想的脂膜，假脂膜和真脂膜，又怎么区分呢？所以我敢说这种说法不妥当。
I have read the discussions on the Sanjiao (Triple Burner) by the *Nan Jing* (Classic of Difficult Issues), Wang Shuhe, Qixuanzi, and other great sages, all of whom stated that it is "named but formless." I also read in the *Ling Shu Jing* (Spiritual Pivot): "Those with dense skin texture and thick skin have a thick Sanjiao; those with coarse skin texture and thin skin have a thin Sanjiao. The brave have horizontal Sanjiao textures; the timid have vertical Sanjiao textures." This seems to imply that it has form. Later, observing Li Shicai (Li Zhongzi, Ming Dynasty physician) stating: "Between the muscles and the Zang-Fu organs lies the Sanjiao," which also suggests it is formless. However, Li Shicai considered the "formless" view erroneous and cited the descriptions of thickness and orientation from the *Ling Shu Jing*, as well as the metaphors of mist, foam, and ditch, to demonstrate its form. Thus, does the Sanjiao ultimately have form or not? I respectfully add a few words to clarify this. The Sanjiao refers to the three empty spaces within the chest, diaphragm, and abdomen. When the great sages said it is "named but formless," they intended to distinguish it from other Zang and Fu organs that possess specific, independent forms. They did not mean that without form there is no location; rather, precisely because it points to these empty spaces, it is called formless. The "thickness and orientation" mentioned in the *Ling Shu Jing* refer to the interior conditions of the cavities of the chest, diaphragm, and abdomen, implying that it does not possess an additional, distinct physical shape characterized by thickness or orientation. The Classics further state: "The Upper Jiao is like mist, the Middle Jiao like foam, and the Lower Jiao like a ditch," while some interpretations describe the Middle Jiao as like dripping liquid. These are likely metaphors for the water vapor and fluids within the empty spaces of the chest, diaphragm, and abdomen. If the Sanjiao had a fixed physical form, then mist is gathered Qi that dissipates at times; foam consists of water bubbles that rise and fall; dripping liquid is residual drops that may or may not exist. All lack constant form, so how can they be compared to the Upper and Middle Jiao? As for the Lower Jiao being like a ditch, this merely uses the water channels in ditches to metaphorically represent the water-draining function of the Lower Jiao, not comparing it to the physical shell of a ditch. Regarding Li Shicai's statement that "between the muscles and the Zang-Fu organs," although there is a location, there is originally no specific form. Why then consider "formless" to be an error? Does his logic imply that if a location exists, it cannot be called formless? However, "location" and "form" are different. The reason the *Nei Jing* speaks of its existence is due to its location; the reason the sages concluded it is formless is due to the lack of specific physical structure. The words of the ancient sages and later scholars appear different but share the same essence. Only Chen Wuzhuo (Chen Yan, Song Dynasty physician) claimed it has form, resembling fatty membranes. I suspect this view is not entirely appropriate. Fatty membranes are pre-existing physical substances in the body. If the form of the Sanjiao were like fatty membranes, it would imply another layer of hypothetical membrane. How could one distinguish between a hypothetical fatty membrane and a real one? Therefore, I dare to say this view is inappropriate.