造化之道，一阴一阳而已矣。阳动阴静，阳明阴晦；阳有知，阴无知；阳无形，阴有形；阳
无体，以阴为体，阴无用，待阳而用。二者相合，则物生；相离则物死。微哉！微哉！通于其说
则鬼神之幽、人物之着，与夫天文地理、医卜方技、仙佛之蕴，一以贯之而无遗矣。
或曰∶天地水火恐未足以尽造化之蕴，不如以阴阳统之。予窃以为阴阳者，虚名也，天地水
火者，物理也，二而一者也。谓天地水火未足以尽造化之蕴，此特未之察耳。盖人知水之为水，
而不知寒凉润泽者皆水也；人知火之为火，而不知温热光明者皆火也。天宰之以神，地载之以形，
水火二者交会变化于其间，万物由之而生，由之而死，造化之能事毕矣。自此之外，岂复有余蕴乎？
周子所谓太极，指神而言。神无所不统，故为太极；神无影，故为无极而太极。朱子所注，
亦得其意，但不言神而言理，故读者未即悟朱注上天之载盖指神而言也。殊不知太极乃阴阳合而
未分者也，阴形阳神皆在其中。及分为阴阳，则阳为天火，依旧为神；阴为地水，依旧为形。若
太极本体止有神而无形，则分后地水之形何从而来哉？由此化生人物，其心性之神则皆天火之神
所为也，其血肉之形则皆地水之形所为也。此理先圣屡有言者，但学人忽而不察耳。盖有形易见
而无形难见，固无怪其然也。
The principle of creation is nothing more than Yin and Yang. Yang moves, Yin is still; Yang is bright, Yin is obscure; Yang has consciousness, Yin lacks consciousness; Yang has no form, Yin has form; Yang has no substance, relying on Yin as its substance; Yin has no function, awaiting Yang to activate its function. When the two combine, things are born; when they separate, things die. How subtle! How subtle! To understand this theory is to贯通 (penetrate/connect) all matters: the hidden nature of ghosts and spirits, the manifest nature of humans and creatures, as well as astronomy, geography, medicine, divination, arts and skills, and the mysteries of Daoism and Buddhism—all are integrated without omission.
Some say: Heaven, Earth, Water, and Fire may not be sufficient to exhaust the mysteries of creation; it is better to unify them under Yin and Yang. I privately believe that Yin and Yang are abstract names, while Heaven, Earth, Water, and Fire are physical realities; the two are essentially one. To claim that Heaven, Earth, Water, and Fire are insufficient to exhaust the mysteries of creation is merely a failure to observe carefully. People know water as water, but do not realize that coldness, coolness, moistening, and nourishing properties are all manifestations of Water. People know fire as fire, but do not realize that heat, warmth, brightness, and illumination are all manifestations of Fire. Heaven governs with Spirit (Shen), Earth carries with Form (Xing). Water and Fire interact and transform within them; all things arise from this and perish through this. The capabilities of creation are thus complete. Beyond this, could there possibly remain any further mystery?
Zhou Dunyi’s reference to "Taiji" (Supreme Ultimate) refers to Spirit (Shen). Because Spirit encompasses everything, it is called Taiji; because Spirit has no shadow (is formless), it is described as "Wuji er Taiji" (Non-Polar yet Supreme Ultimate). Zhu Xi’s commentary also grasps this intent, but by discussing "Li" (Principle/Rationality) instead of "Shen," readers fail to immediately comprehend that his annotation "Shangtian zhi zai" (The workings of High Heaven) actually refers to Spirit. It is unknown that Taiji is the state where Yin and Yang are combined but undifferentiated, containing both Yin-Form and Yang-Spirit. Once differentiated into Yin and Yang, Yang becomes Heaven-Fire, retaining its nature as Spirit; Yin becomes Earth-Water, retaining its nature as Form. If the original substance of Taiji possessed only Spirit and no Form, from where would the Form of Earth-Water originate after differentiation? Thus, in the generation of humans and creatures, the Spirit of their mind and nature is the work of Heaven-Fire's Spirit, while the Form of their flesh and blood is the work of Earth-Water's Form. This principle was frequently stated by ancient sages, but students often neglect it and fail to observe. Since what has form is easy to see, and what lacks form is hard to see, this is indeed not surprising.