There is a traditional saying: "When Heaven and Earth are
united, the generative force achieves its quintessence; when yin
and yang wane and wax, [respectively], transformations are seasonable."
If the time is right, the result is order; if the time is wrong,
the result is confusion. Now man at birth is incomplete in five
respects: his eyes are without sight, he cannot eat, or walk, or
speak, or reproduce. By three months he can focus his eyes,[2]
and
then he can see; by eight[3]
months he grows teeth, and then he can
eat; by one year his kneecap is formed,
[4]
and then he can walk;
by three years his skull has grown together,
[5]
and then he can
speak; by sixteen the semen passes and then he can reproduce.
Yin and yang revert from one to the other.[6]
Yin is linked in
its transformations to yang, and yang is linked to yin. Now a
boy grows teeth at eight months; he loses his milk teeth at eight
years; at sixteen the semen develops and to some extent passes.
A girl grows teeth at seven months; she loses her milk teeth at
seven years, and at fourteen her fluids develop and to some extent
flow. Thus in their transformations yang is linked to yin and yin
is linked to yang.[7]
Now when in an unworthy person sexual change is complete,
the generative force is stimulated; his sexual feelings are excited,
and he gives free rein to his desires, going against and upsetting
his reproductive activities,[8]
and so dying prematurely, fails to
enjoy long life. The Ode says,[9]
That person
Has his heart only on being married.
Greatly is he untrue to himself,
And does not recognize [the law of] his lot.
It is not thus with the sage. When his sexual vitality is overflowing,
he thinks of getting posterity. He regrets that the occation
cannot be taken advantage of,[10]
but if he has no regular way
out, he then gives vent to his feelings and desires in singing of
the Way and of i. The Ode says,[11]
How lovely is the retiring girl!
She has to await me at a corner of the wall.
Loving and not seeing her,
I scratch my head, and am in perplexity.
Look at that sun and moon![12]
Long, long do I think.
The way is distant;
How can he come to me?
These are words referring to an urgent occasion. This is why it
speaks of the sun and moon.
