Ta Chuan / The Great Treatise   CHAPTER VI. On the Nature of the Book of Changes in General   1. The Master said: The Creative and the Receptive are indeed the gateway to the Changes. The Creative is the representative of the light things and the Receptive of dark things. In that the natures of the dark and the light are joined, the firm and the yielding receive form. Thus do the relationships of heaven and earth take shape, and we enter into relation with the nature of the light of the gods. (Wilhelm/Baynes, The I Ching, 1950 Bollingen Foundation, Inc. pps. 343-344)   So much good stuff is packed into this single paragraph. I don't know where to begin. Wilhelm gives his own interpretation, which is quite good. One item that I don't see Wilhelm comment upon specifically is the wording light things and dark things. I find it odd that there are things with the quality of light and dark. Light and dark are not things in themselves. It's not The Light or The Dark, rather it is something else to which light and dark are attributes or descriptors. This harkens back to DDJ chapter one where Lao Tsu says "The Tao that can be told is not the eternal Tao. The name that can be named is not the eternal name." (Feng/English, Tao Te Ching, 1972 Vintage Books) In DDJ Tao is also a descriptor. It's not the thing itself but rather a placeholder for the thing that has no name.   This is basic stuff but easy to overlook and easier to forget.