The Principle of Unity, as an extension of the Principle of Duality, does not apply only to the manifest world of form. The first bifurcation in the Universe happens when dual forms arise from Nondual Formlessness, which is the essence of the mystical worldview, which we can simply call Wholeness. The Principle of Duality then becomes the Principle of Unity, which states Wholeness is the union of all opposites, with a similar primary-secondary relationship between Nondual Wholeness and the dual world of form, illustrated in this diagram.
The Principle of Unity—the Sacred Marriage of all opposites—is thus a universal, irrefutable truth, the Ultimate Integral Tantric Yoga, for yoga means ‘union’, as does tantra symbolically. Heraclitus aptly called this fundamental design principle of the Universe the Hidden Harmony, for human beings have been constantly denying this most basic of all truths for thousands of years, living in disharmony, in conflict and suffering, not in Love and Peace.