The nature and progression of disease can also be understood using this pattern. When a disease develops rapidly, it is in the acute or yang stage. As it progresses and becomes more chronic, thus it enters the yin stage. Usually, acute diseases affect the surface or superficial aspects of the body while chronic diseases have already overwhelmed the body's defenses and gone deeper into the interior. In addition, regardless of location or duration, disease can be classified by its affects. Extreme, severe symptoms are considered excess and are consequently yang. In contrast, mild or diffuse symptoms accompanied by weakness are considered deficient and are therefore yin. With regard to diagnosis, that which is internal, cold, deficient or chronic is considered yin. That which is external, hot, excess or acute is considered yin. When conflicting signs are present it usually points to a more complex condition and the TCM practitioner must evaluate all the symptoms together to determine the appropriate treatment strategy.
In summary, it should be evident that the designations of yin and yang are universal and extend into every aspect of life. Because of its ubiquity, this theory is a very useful tool for understanding natural phenomena and therefore can be an indispensable diagnostic aid. While this is an ancient paradigm it is not primitive and though simple it can be developed into surprising complexity. The only limitation of the application of this universal truth is one's own perception and imagination.
References:
Tao, The Subtle Universal Law and the Integral Way of Life , by Hua-Ching Ni, 2nd edition, Seven Star Communications, Santa Monica, CA. 1979
Between Heaven and Earth, A Guide to Chinese Medicine , by Harriet Beinfield and Efram Korngold, Ballantine Books, New York 1985
Analysis of Chinese Characters by G.D. Wilder and J.H. Ingram, Dover Publications, Inc. New York 1974 醫(yī) 學 全 在 線zxtf.net.cn
The Web That Has No Weaver by Ted J. Kaptchuk, Congdon and Weed, Inc. Chicago Il. 1983
