The one essence is the essence of Thusness, or the pure mind. It is called luminous or completely illumined, and inherently pure.
Inherent purity refers to the non-duality of being and emptiness —emptiness is called inherent purity, beyond conception.
The luminosity or complete illumination of being is the state before the dichotomy of subject and object and the development of false consciousness based on this dualism.
—Fa-tsang, Return to the Source