The word ku, here and elsewhere translated "valley," is one of Lao-tzu's difficult key-words. All authorities agree that the word as used in the Tao-teh-king does not refer to the visible vale in which vegetation grows, but to the empty (?) space enclosed by the hills—a characteristic example of our author's fine power of compression.

It is significant that Lao-tzu's concept of space is never an endless extension without limitation, but always something that is bounded—the space confined between two hills, a valley. Two ideas are here suggested: 1. That cosmic-space is a portion only of the illimitable field, marked off or set apart by the Eternal, within which his activities operate. This is bounded by two eternities—a manvantara between pralayas. 2. That creation is a valley, a self-limitation or humiliation of the All-Consciousness.

Hence in the text the "Valley-God" (or Spirit, the original is incapable of exact definition) corresponds to Aditi, "The Boundless" (Akâsha), otherwise known as the Deva Matri or the Mother of the Gods (Cosmic Space). We have still another aspect of Her in the Rig Veda, where she is described as Vâch, "Mystic Speech"—the root whence Occult Wisdom proceeds. We meet her again in the teaching of the Kabalists as the Female Logos, or Sephira, the mother of the Sephiroth. In the Old Testament we find her personified as Wisdom, the Chokmah, or male Sephira of the Zohar, for, as Philo

points out, THIS is both male and female—perfect wholeness.

The commentator Su Cheh says: "The epithet 'valley' here applied to God (or spirit) expresses existence in the midst of non-existence, and as THAT is unborn, it is undying. It is called God (or spirit) to express its perfections, and 'Mother of the Abyss' because of its achievements. All Nature springs from The Mother, who is called abysmal, because, while we can perceive what She produces, her methods of production remain inscrutable."

The word ku recurs in chaps. 15, 28, 32, 39, 41 and 66, but not again in this connection.