The
School of Naturalists or the
School of Yin-yang (陰陽家/阴阳家;
Yīnyángjiā;
Yin-yang-chia; "School of Yin-Yang") was a
Warring States era philosophy that synthesized the concepts of
yin-yang and the
Five Elements;
Zou Yan is considered the founder of this school. His theory attempted to explain the universe in terms of basic forces in nature: the complementary agents of yin (dark, cold, female, negative) and yang (light, hot, male, positive) and the Five Elements or Five Phases (water, fire, wood, metal, and earth). In its early days, this theory was most strongly associated with the states of
Yan and
Qi. In later periods, these epistemological theories came to hold significance in both philosophy and popular belief. This school was absorbed into the
alchemic and magical dimensions of
Taoism as well as into the
Chinese medical framework. The earliest surviving recordings of this are in the
Ma Wang Dui texts and
Huang Di Nei Jing.