Granet⁸ writes about pre-feudal Chinese religion dating back some four to six thousand years ago as patterned from the rhythm of peasant life. The family worked in the fields during the summer, they slept in the fields, the women and children took food to the men in the little temporary huts in the fields, it was summertime, it was sunlight, and then with the fall harvests the work in the fields was completed. At that point everything moved into the round kiln-shaped mud hut which was the woman's world. The harvest was complete, the grain and food for the winter was stored in the hut. In the winter during the worst periods of weather, the animals were invited in and slept in the hut with the family. It was dark. Coitus took place in the hut, with the animals and the stored grain. This was the time and area of fertilization. This was the time of rest. This was woman's world. Then the light returned. With the festivals of spring and the rituals of planting and marriage, life and its activities moved outside into the world of light, into the fields, into the man's world.
 
Thus Granet makes clear that the familiar Tai Chi symbol is derived historically from a physical, agricultural reality. Its origin is not an abstract idea; it is a literal representation of the movement of light to dark and dark to light as experienced in the seasonal cycle of the year, from the male time of activity and productivity to the female time of rest and generation. It symbolizes all these things because it is a visual metaphor for this circular interaction between polarities. Thus the movement from light to dark, with the seed of the opposite hidden in each phase, is an image of the dynamic process relating the inner and outer worlds.