Two complementary and interconnected forces or principles that exist in all aspects of life. They are fundamental concepts in Chinese philosophy and represent the duality and interdependence of opposite and complementary elements. Yin is associated with qualities such as darkness, passivity, femininity, intuition, and receptivity, while yang is associated with qualities such as light, activity, masculinity, logic, and assertiveness. The concept of yin and yang emphasizes the balance and harmony between these opposing forces, as well as their constant interaction and transformation. It symbolizes the dynamic and interconnected nature of the universe.