Yin and Yang
Yin and yang are ancient daoist philosophical concepts that describe the universe and everything in it as being divisible into two principle categories that balance and compliment each other. In nature examples of this include night and day, moon and sun, winter and summer, plain and mountain, ocean and desert. Within our bodies, yin and yang are reflected in things like the balance of cold and heat, dryness and moisture, activity and rest, and in the interdependent relationship of our tangible, physical being with our immaterial, mind and spirit. At its core, the theory of yin and yang expresses the true nature of all phenomena as it continually shifts and cycles in and out of phase. There are four universal laws that govern the relationship between yin and yang that apply to everything in existence, including us.