I Ching states:
“I is aligned to Heaven and Earth.
Thus it encompasses the
Tao of Heaven and Earth.
It explains not only the observable world
but also the unobservable world of spirits.
It embraces the law of beginning, end, and
regeneration of all phenomena
and matters.
It knows that all matters are formed by
spirits and vitality, and
the soul governs the changes
of the matters”.
The generic term “soul” is actually a trichotomy of the soul, Hun, and Po. 16 The soul is the pivot of a man’s life or death. When the human body grows, the soul disperses into the nerve endings to form the Hun and the sensual organs to form the Po.
The Hun consists of three components:
the first component is the Sheng-hun (Spirit of Growth),
the second is the Jue-hun (The Spirit of Awareness), and
the third is the You-hun (The Spirit of Thought and Inspiration).
(You-hun is what most people refer to when they speak of “soul”.)
The Po in the sensual organs,
i.e., the eyes, ears, nose, tongue, body, and mind, generates the six desires.
The six sensual organs then generate the seven emotions of happiness, rage, sadness, joyousness, love, hatred, and lust. These are the seven components of the Po.
When one deals with other people and attends to various daily chores, his Po generates desires and emotions and is expended by converting into physical energy. That also depletes the souls to the extent that it cannot be restored to its original True Self and cannot return to God’s kingdom.
While the True Self is the essence of the human life, the Hun and the Po are the human life. That is why all Saints preached the doctrine of practicing both the True Self and the life.
The Qi of Hun and Po is just like an invisible bond linking the soul and the body.
They function as a medium synchronizing the soul and the body. The Qi of Hun and Po is called the “silver ribbon”. When the True Self resides in the body, one is alive. When the True Self departs from the body, one dies.
When a person is alive, his Hun resides in the liver and his Po resides in the lung. When the Hun and Po reside in the body, one is alive. When the Hun and Po leave the body, one dies.

The You-hun is the seed for the cycle of birth, death, and rebirth.
When a person dies, his Sheng-hun stays at the funeral hall while his Jue-hun stays at his grave. His You-hun reports to Hell for judgment. It is the You-hun which becomes a human or ghost, a Saint or a Sage, the good or the bad, or an animal.
The True Self is the first to enter the body before birth and the first to leave the body upon death.
At the moment an infant gives his first cry, the Hun enters his body. When the Hun enters the body, the True Self is connected with the Qi of Hou-tien (oxygen); the Hun is now dependent on the body to manifest itself.
If the You-hun does not enter the body, even with the True Self, the infant cannot live. That is why infants must cry at the time of birth in order to live.
The Po depends on the coagulation of vitality and the Qi in Hou-tien for existence. It takes forty-nine days after birth for the seven components of the Po to become fully established. Similarly, the seven components will not totally vanish until forty-nine days after death.
The word “It” in the statement of the Heart Sutra:
“It cannot be created or destroyed.
It cannot be contaminated or purified.
It cannot be enhanced or degraded.”
refers to the True Self.
The True Self
cannot be drowned in water, nor burned in fire. The True Self resides in a different body for every life, just like one moves from a house to another; the True Self does not change.
The True Self always resides in the Right Portal. It reigns the entire body without entering nor exiting.
That is why in order to practice Tao, one must first focus his effort on the True Self.