Yin is cold, shady, static, inward, descending, and matter. Yang is warm, bright, moving, outward, ascending, and energy. Yin contains the seed of Yang, and Yang contains the seed of Yin. Interaction and balance between the two maintains the development and unity of all natural phenomena in the universe.
The Yin–Yang concept originated from the observation and summarization of natural phenomena. Every phenomenon is in a constantly changing status, in an endless cycle, and in motion between two poles. Night–day and inactivity–activity are two Yin–Yang phases. Yin is night and inactivity; Yang is day and activity. Yin constantly changes into Yang, and vice versa.
The Yin–Yang vacillation applies to many other natural phenomena, such as cyclical changes in the four seasons , movement of the moon and sun, and the rise and fall of the tide. Matter–energy transformation is a universal phenomenon. Matter is transformed into energy when wood burns to generate heat. Yin matter (wood) is transformed into Yang energy (heat). Energy is transformed into matter when vapor condenses into water. Yang energy (vapor) is transformed into Yin matter (water). Yin and Yang are two forms of matter–energy transformation, or two states of matter’s density in change and transformation. The Inner Canon of The Yellow Emperor states, “The lucid Yang Qi ascends to form the heaven, while the turbid Yin Qi descends to form the earth”
Highlights of the Yin–Yang Concept
- Yin is cold, shady, static, descending, and matter; Yang is warm, bright, moving, ascending, and energy.
- Yin and Yang represent the unity of opposites. The relation between Yin and Yang is a dynamic balance.
- Yin and Yang are two phases of a cycle, e.g. night and day in the daily cycle, or winter and summer in the seasonal cycle.
- The seed of Yin contained in Yang or the seed of Yang contained in Yin is the motive for change and development for every object or phenomenon in the universe.
- Yin and Yang are two states in matter–energy transformation.
A solid understanding of the Yin–Yang concept may allow the application of this theory to natural, social, and other phenomena in daily life.