能愈病之非难，知病之必愈、必不愈为难。夫人之得病，非皆死症也。庸医治之，非必
皆与
病相反也。外感内伤，皆有现病，约略治之，自能向愈。况病情轻者，虽不服药，亦能渐痊
。即病势危迫，医者苟无大误，邪气渐退，亦自能向安。故愈病非医者之能事也。惟不论轻
重之疾，一见即能决其死生难易，百无一失，此则学问之极功，而非浅尝者所能知也。夫病
轻而预知其愈，病重而预知其死，此犹为易知者。惟病象甚轻，而能决其必死；病势甚重，
而能断其必生，乃为难耳。更有病已愈，而不久必死者。盖邪气虽去，而其人之元气与病俱
亡，一时虽若粗安，真气不可复续，如两虎相角，其一虽胜，而力已脱尽，虽良工亦 能救
也。又有病不愈，而人亦不死者。盖邪气盛而元气坚固，邪气与元气相并，大攻则恐伤其正
，小攻则病不为动，如油入面，一合则不可复分，而又不至于伤生。此二者，皆人这所不知
都民。其大端，则病气入脏腑者，病与人俱尽者为多；病在经络骨脉者，病与人俱存者为
多。此乃内外轻重之别也。斯二者，方其病之始形，必有可征之端，良工知之自，自有防微
之法。既不使之与病俱亡，亦不使之终身愈，此非深通经义之人，必不能穷源极流，挽回于
人所不见之地也。
能够治愈疾病并不困难，难的是预知疾病是必然痊愈还是必然不愈。人得病，并非都是死症。庸医治疗，未必都与病情相反。外感病和内伤病，都有明显的病症表现，大致进行治疗，自然能趋向痊愈。况且病情轻的，即使不服药，也能逐渐康复。就是病势危急紧迫，医生如果犯大错，邪气逐渐消退，也自然能趋向平安。所以，治愈疾病并不是医生的主要本事。只有不论病情轻重，一见就能断定其生死难易，百无一失，这才是学问的最高境界，不是浅尝辄止的人所能知道的。
病情轻而预先知道它会好，病情重而预先知道它会死，这还算容易知道的。只有病象看起来很轻，却能断定它必然死亡；病势看起来很重，却能断定它必然生存，这才是难的。更有已经痊愈，但不久后必然死亡的。这是因为邪气虽然去除了，但人的元气随着疾病一起耗尽了，一时之间虽然看似粗略平安，但真气无法再接续恢复，就像两只老虎相斗，其中一只虽然获胜，但力气已经耗尽，即使是高明的医生也无法挽救。又有病没有痊愈，但人也不会死的。这是因为邪气旺盛而元气坚固，邪气与元气相互纠缠，大力攻伐恐怕损伤正气，小力攻伐则对病邪不起作用，就像油混入面粉中，一旦混合就无法分开，但又不至于伤害生命。这两种情况，都是普通人所不知道的。其主要规律是：病气侵入脏腑的，病与人一同终结的情况较多；病在经络骨脉的，病与人共存的情况较多。这是内外轻重的区别。在这两种情况下，当疾病刚开始显现时，一定有可以征验的迹象，高明的医生知道这一点，自然有防微杜渐的方法。既不让它随疾病一起消亡，也不让它终身不愈，这不是深通中医经典义理的人，一定不能穷究本源和流变，在人们看不见的地方挽回局面。
It is not difficult to cure a disease; it is difficult to know whether the disease will inevitably recover or inevitably fail to recover. When people fall ill, not all cases are fatal. Quack doctors treat them, and their treatments are not necessarily contrary to the nature of the disease. For both external contraction (Wai Gan) and internal injury (Nei Shang), there are present manifestations of the disease. Rough treatment will naturally lead to recovery. Moreover, in mild cases, even without medication, gradual recovery can occur. Even in critical conditions, if the physician avoids major errors, as the pathogenic factors (Xie Qi) gradually recede, the patient will naturally tend toward peace. Therefore, curing the disease is not the primary capability of the physician. Only by being able to determine life and death, ease and difficulty, at first sight regardless of the severity of the illness, with almost no failure, can one achieve the highest merit of learning, which is beyond the comprehension of those who have only superficial knowledge.
To predict recovery for mild diseases and death for severe diseases is still relatively easy to understand. It is difficult, however, to predict inevitable death when the symptoms appear very mild, and to predict inevitable survival when the condition appears very severe. Furthermore, there are cases where the disease seems cured, but death follows shortly after. This is because although the pathogenic factors have been expelled, the person's Yuan Qi (Primordial Qi) has perished along with the disease. Although there is a temporary rough stability, the Zhen Qi (True Qi) cannot be restored. It is like two tigers fighting: although one wins, its strength is completely exhausted, and even a skilled artisan cannot save it. There are also cases where the disease does not heal, yet the person does not die. This is because the pathogenic factors are vigorous while the Yuan Qi is solid. The pathogenic factors and Yuan Qi are intertwined; aggressive attack risks damaging the healthy Qi, while mild attack fails to move the disease. It is like oil mixing into flour; once combined, they cannot be separated, yet it does not lead to death. These two scenarios are unknown to ordinary people. The general principle is: when pathogenic qi enters the Zang-Fu organs (Zang Fu), the disease and the person often perish together; when the disease is in the meridians, collaterals, bones, and vessels, the disease and the person often coexist. This distinguishes between interior/exterior and light/severe conditions. At the initial stage of these two types of diseases, there must be signs to indicate the trend. Skilled physicians, knowing this, will naturally employ methods to prevent minor issues from escalating. They neither allow the condition to perish with the disease nor let it persist for life. This requires someone who deeply understands the principles of the classics to trace the source and flow, and to intervene in ways unseen by others.