Then energy-power is known as two types, the bright and thus the dark;
Of these, the bright and the dark, there is no co-existence.
Commentary
Energy-power is of two types, the bright and the dark, and other pairs can be formed like knowledge, non-knowledge, happiness-suffering, etc. In the Vivekachudamani (verse 110 ff) Sankaracharya speaks about the veiling and projecting powers of illusive relativity. The Varaha Purana says this about Sakti: "Her dark energy power is called Raudri... Her clear energy-power is called Brahmi."
The sage further says that the bright and the dark cannot co-exist. They are a dualistic pair and each one is limited to its own sphere. Supreme Sakti is the Absolute beyond duality. The Sarasvatirahasya Upanishad (verses 52-53) has this interesting statement about illusive relativity: "Illusive relativity has two energy-powers, one is projection (and) the other is concealment; the first projects the cosmos, all that is subtle and gross. The second (energy-power) conceals, being inward like an abyss between the seer and seen, as well as being outward like an abyss between emanation and the Absolute; illusive relativity causes endless cosmic becoming."