中文摘要：

中医学中的阴阳具有多重含义。该文从起源于西方的逻辑学和哲学的角度对其内涵进行界定，以阴、阳代表事物的相对属性，以阴阳代表事物之间的关系，发现阴与阳之和为常数，阴阳是一类特殊矛盾；从黄赤交角造成的四季光照度变化，推得太极图中的曲线是两条阿基米德螺线，表征了自然界最基本的周期运动——简谐振动。

英文摘要：

Yinyang in Chinese medicine has several kinds of meaning. Based on the Western logic and philosophy, the paper defined Yin, Yang as relative attributes, Yinyang as relationships. It is found that the sum of Yin and Yang is a constant. Yinyang is a series of special contradictions. The obliquity of ecliptic results in the seasonal rhythm of solar illumination. It is deduced from the rhythm that the curves in Taiji Graph are two Archimedes helices. Taiji Graph reflects the most basic cyclical motion, the simple harmonic vibration.