The earth was (is) the home of the ancestors. The spiritual powers of all creatures which lived before and passed their energy and values on to the living. The earth herself contains huge energies. If we do not reckon with these energies, bad fortune and disease will befall us. If we listen to the earth and revere her (and like in old times "revere the ancestors"), we will find happiness and health. Kun is not only the planet, and not only the fertile stuff under our feet. It is the container of unimaginably great powers.
Everywhere and in all times the goddess of earth was revered as bringer of fertility and peace.
Kun1 is composed of 1: TU3, earth, either a clog of earth. 2: SHEN1, meaning stretch-out, spirit, ghost, explain, to state, express, power of expression or lightning. In it’s oldest version it is written more or less like a double spiral: a picture of lightning. In many old cultures the spiral was a symbol of the primordial waters, the upper ones represented the formless potentiality, the lower ones the potential of form. Together the full potential of manifestation. The spiral is the rhythm of life, of birth and death, the expansion and contraction of yin and yang. And also thunder and lightning, the dynamic of life.
passive force of realisation, receptivity, compliance, obedience,
female, feminine. Nature and space. The spirit or vitality of life.
In the Mawangdui Yijing hex.2 is CHUAN, the flow, stream or water, maybe the female organ. An old way or writing 3 broken lines is also like the character chuan.
See Hsarmen's article "The land bestowed is great"
The trigrams: Earth above Earth.
The basic disposition of earth is female. The noble one carries everything with great generosity.
About the spiral: Williams, Penguin Dictionary of Symbols, page 907. see link Books