[12] These two have the same source..." denotes the fact that both Being-without-form and Being-within-form derive from the same source-the Dao. Some scholars (e.g. Tong Shuye) have proposed that Wu (Being-without-form) and You (Being-withinform), miao (subtlety) and jiao (manifestation) all merge but have different names. In view of tong (togetherness) they appeared so inseparable that they were called xuan (deep and profound).
[13] The Chinese notion xuan is rendered here as "deep and profound," and Being-without-form and Being-within-form as two aspects of the Dao are characterized with such implications as inseparability due to their interrelationship, unpredictability due to their changeability and indescribability or unnameability due to their subtlety.
Chan Wing-tsit translates xuan as either "profound" or "mysterious." He holds that the word itself has a wide range of meanings, as have many other Chinese words. It means dark, abstruse, deep, profound, secret, mysterious, etc. In Daoist religious point of view, the aspect of mystery should be stressed, but in Daoist philosophy, the profound or metaphysical aspect is paramount. Thus xuan-xue should be translated as "metaphysical school," while xuan de should be translated as "profound and secret virtue." These expressions simply have to be understood in their contexts. Xuan ming, for example, is not just "profoundly dark," it also means noumenon (see Chan Wing-tsit. A Source Book in Chinese Philosophy. Princeton, 1973, p. 788).
[14] "The doorway to all subtleties" here refers to the Dao as an all-embracing principle of the myriad things and their endless changes. Since the Dao is the unity of Being-without-form and Being-within-form, it operates at a deeper and more profound level, creating Heaven and Earth, and generating and transforming all things.
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Commentary:
Talking about the Duo, Lao Zi proclaims first of all that language as an instrument for communication is rather limited in terms of its expressiveness. Thus he concludes that "the Dao that can be told is not the constant Dao." It is noteworthy that this observation could date back more than 2,500 years. Historically speaking, it has generated a continuous impact on the development of Chinese theories, experiences and artistic creation in general. This can be testified to, for instance, such conceptions as "It can be perceived but not communicated," "Words are forgotten when implications are obtained; implications are abandoned when imagery is realized," "All the significance and aura are achieved without writing down a single word," "Try to get hold of the inner spirit and go beyond the external shape," and so on. Hence the notion that any verbal language is limited in expression tends to influence the Chinese way of thinking in general, and that of contemplating artworks in particular. These hidden influences will be further clarified as our scrutiny and discussion of the Dao De Jing advance.
In spite of his assertion that "the Dao that can be told is not the constant Dao," Lao Zi still wrote more than 5,000 words in a poetic form to present his ponderings on and expounding of Dao as a key notion in his philosophy. In his book, the Dao has always to be understood in its specific context. It contains such categories of meanings as follows:
(1) The proto-material or substance which constitutes the universe;
(2) The potential driving force that creates all things;
(3) The underlying law related to the motion and development of all things; and
(4) The standard or code with which to measure human conduct.
The Dao discussed in this chapter has a double (i.e. both metaphysical and physical) significance. It is so subtle and profound that it is indescribable and unnameable in ready-made words or concepts. It functions as the ultimate beginning of Heaven and Earth, and as the original source of all that exists. Thus it enjoys infinite potential and creativity. As a matter of fact, the flourishing and transforming of everything between Heaven and earth merely manifest the continuous working of the Dao's potential.
Being-without-form (Wu) and Being-within-form (You) signify two aspects of the Dao in Lao Zi's conception. They are employed to demonstrate a dynamic process of the Dao from its invisible state toward its visible state. The interrelationship between these two facets of the Dao seems analogically identical to that between name and object or thinking and being.
Some scholars tend to use such terms as "Non-being" for the Daoist concept of Wu and "Being" for You. However, it is imperative to point out that this "Non-being" in Lao Zi's thought does not mean "nothing." It is something real both in existence and in effect. It reflects the invisible or hidden character of the Dao as a kind of potentiality beyond our sensory perception. We assume that the concept Wu is used by Lao Zi to describe the state of the Dao before it achieves its actuality or manifestation-You. It is also worth stressing that the Daoist concept of "Being" is far different in meaning from the "Being" as expounded and articulated by Parmenides and Plato. This is just because the former, as the manifestation of the Dao, can be concrete and many, whereas the latter, owing to its transcendental trait, remains abstract and one. In short, the former is said to be a material kind of being, while the latter is an immaterial kind of being.

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