Heng Tao represents the true reality of nature. In order to adequately cover Heng Tao as a whole, Lao-tzu chooses two opposite names to cover the whole domain in Verse 2. He defines two objects, Wu 無and Yu有, to represent the two separate parts (sub-domains) of Tao. These parts cannot represent the reality of Tao as a whole, but they can be used to describe the manifestations of Tao. Lao-tzu uses Verse 3 to introduce two true manifestations of Tao as Heng Wu恆無 and Heng Yu恆有. Heng Wu and Heng Yu are true or Heng Names; they have reality. These true manifestations will have wholeness to represent Heng Tao.
We can describe Heng Names with names. In Heng Wu, we have Wu, but we also see in it the “appearances (Yu).” In Heng Yu, we have Yu, but we also see in it the “fading boundaries (Wu).” Therefore, each true manifestation is a mixture of both Wu and Yu. Both manifestations thus recover the wholeness from the fragmentation of Wu and Yu. That is, a Heng Name cannot be represented by a single name, but can be represented with both opposite names together. Both names must participate in each true manifestation.
In summary, Lao-tzu first defines Wu and Yu to describe the myriad things, but he soon finds out that neither Wu nor Yu can describe the true order of the myriad things. Only the complementarity of Wu and Yu can describe the true relationship of the myriad things. He calls these complementary states of Wu and Yu: Heng Wu and Heng Yu.
In Verse 4, Lao-tzu further states the mystery that the true manifestations are simultaneous and equivalent manifestations for the same principle of Tao. Finally, in Verse 5, he characterizes the two manifestations as profound 玄. By profoundness, Lao-tzu means that the manifestations cannot be distinctively described as Wu or Yu, or in our ordinary language. It may also mean that we cannot clearly distinguish the two manifestations. All manifestations are “vague and indeterminate” and will appear mysterious to our mind. All mysteries of Tao are in the profoundness of these two manifestations.
Profoundness has a well-defined meaning in our model. If we can understand the nature of this profoundness of these manifestations, we will understand the core mystery of Tao. This means that Tao as an absolute reality can be described by describing the mysterious manifestations of Tao in the phenomenal world. Overall, Chapter 1 sets a positive tone in our ability to discuss Tao.
 Two opposites can conveniently cover a whole domain with two subdomains. It is often called a “bifurcation.”
 Complementarity means that two opposites complement each other to describe the reality.