Originally the world contained nothing but emptiness. It all commenced with the appearance of day and night, and then that of spring, summer, autumn and winter. Afterwards, the eight elementary substances, heaven and earth, fire and water, wind and thunder, as well as mountain and marsh, were formed. With their development the world was at last full of variety.
A spaceless and timeless world (無wu2極ji2, no ridgepole, in Yi’s terminology, which means no boundary, like that of an inexistent house or world owing to lack of a ridgepole for its roof or dome)
In the beginning there was neither space nor time; the matrix of the cosmos existed in a form of invisible energy, wherein the positive and the negative ones were equal and integrated. Later on the two energies started circling and polarities, i.e. the origin of the whole creation, were created.
The polarities (兩liang3儀yi2, two regulated categories, like two semi-domes of the heavens which are divided and sustained by a ridgepole)
The polarities are composed of Yang and Yin which emerged from the heavens in the form of brightness and darkness, like day and night. These two are opposites but symbiotic as shown on Tai4 Ji2 Tu2 (太極圖, i.e. a drawing of the great ridgepole); one is white while the other is black; white has black in its centre and black has white in its centre. When one increases, the other will decrease; and when one decreases, the other will increase.
Yang is converted into things of masculinity and expresses itself on the earth in the form of largeness, firmness (or rigidity) and strength, as well as the male, and presents itself in terms of hexagram as the masculine line ; the masculine tends to move.
Yin is converted into things of femininity and expresses itself on the earth in the form of smallness, softness (or tenderness) and weakness, as well as the female, and presents itself in terms of hexagram as the feminine line ; the feminine tends to remain still.
In Chinese culture, Yang and Yin additionally refer to opposites in some other respects, for instance, good and evil (in terms of personality, a gentleman and a villain), existence (expressed in various different forms, such as solidness, fullness, etc.) and inexistence (such as hollowness, void or emptiness, etc.), this world and the realm of the dead, warmness (created by sunlight) and coldness.
Four dualities (四si4象xiang4, four phenomena, like those of dawn, midday, dusk and midnight created by the revolution of the heavens)
Once Yang (in the form of brightness) and Yin (darkness) start to interplay, time comes into existence as darkness changes to brightness at dawn, and then brightness starts to develop; after brightness reaches its peak at midday, it will decline; at dusk brightness changes to darkness.
With the reciprocal increase and decrease between Yang and Yin in the form of warmness and coldness, spring, summer, autumn and winter are created. The revolution of day and night, as well as four seasons makes the Qi (氣) of the world move. Qi is an invisible power which is permeating the human body and the world.
Eight trigrams (八ba卦gua4, i.e. eight symbolic signs for the eight elementary substances in the world)
Qi circulates and the world is created. The world is basically composed of heaven, earth, and life. Hereby the trigram is borne in the form of those three essences (參san3才cai4, i.e. three sprouting plants which are teeming with abilities to flourish): earth, humanity and heaven.
Heaven and earth are positioned; the mountain and the marsh are shaped; the thunder arouses all life; the wind starts blowing; fire is ignited and water condenses; the eight elementary substances of the world are created.
The polarities give birth to four dualities, and the four dualities create eight trigrams; hence Qian, Kun, Zhen, Xun, Kan, Li, Gen and Dui are formed, respectively.
Thus the eight elementary substances are represented by eight trigrams, respectively, in accordance with the image of each trigram and its relevant characteristics.
Qian2 features creativeness and perseverance, and denotes heaven. It is composed entirely of the masculine lines. As the masculine is strong and firm, the three masculine lines act together signifying perseverance like the heavens persisting with their revolving day and night, season after season. Therefore it represents heaven, and its dignity is like that of Heaven. As Heaven originates the world, it is symbolic of creativeness.
features submissiveness and denotes earth. It is composed
the feminine (tender) lines; therefore it is submissive as earth
faithfully sustains the heavens. It also features receptiveness
and expansiveness as earth accommodates the whole of creation and
expands endlessly to the horizon.
In ancient times people didn't know that the Earth exists in the
form of a planet;
therefore earth in the I Ching stands for the land on which humans live.