Yin and yang is a way of seeing life. It is a way of bringing order, harmony and change into our lives. Once we know about this principle, we start to see things in a different way. Things start to come to life. Our education teaches us to look at things in a very static way, that something has a certain state and that’s what it is.
But if we look around, we can see that everything is constantly changing. All things are constantly harmonizing and balancing each other.

In essence, everything is dominated by an excess of yin or yang force. We consider everything coming down towards the center of the earth as yang. Everything moving away from the center of the earth we call yin. Yang means centripetal force. Yin, conversely means centrifugal force, moving outward.
On the yang side, this centrifugal force creates contraction or we can say more gathering. Whereas yin creates more the opposite, expansion or dispersion, what can be thought of as separation.

On the yang side there is unification. This contraction creates more downward movement. Naturally, yin would be up. As things move down, contracting, gathering, then they start to become more dry and hard. As things are expanding outward they become more wet or humid and soft. Then this downward movement continues, because this is actually a spiral. As we move closer to the center, then activity increases and things move faster, are more active. On the inside, however, they are more inactive, because energy is dispersing outwards.

This activity means an increase in speed, faster movement. Inactivity means a decrease or slower movement. As activity increases, so does the temperature, which becomes hot. Conversely the yin produces coldness. At this point, on the yang side, heat no longer produces further contraction, but the opposite, expansion. Eventually cold is arrived at, and in the same way, cold no longer produces expansion, but its opposite, contraction. And again the cycle continues until we have heat.
Yin in its extreme will become yang. Yang in its extreme will become yin. Yin and yang endlessly alternate. One constantly changes to the other. When we look through the eyes of yin and yang, we start to see everything as a kind of movement in a state of change with a certain direction. Through the framework of this up and down movement, we can interpret nature and just about everything in life, including personal and global health.