Trinity and the Law of Three
The vast majority of the world’s metaphysical systems are binary. They work on the principle of paired, equal opposites. We see great archetypal polarities that are somehow held in balance: male/female, dark/light, conscious/unconscious, good/evil, action/being. Our dualistic minds feel comfortable in that kind of binary swing. Binary systems prefer symmetry and come to resolution in stasis or stillness.
.. Ternary systems have three independent forces coming together to form something new, a fourth thing. Perhaps the simplest example is a braid. You need at least three sections of hair for a braid to hold; the braid is then a new creation. The interweaving of threeness results in something that didn’t exist before. It is not just a swinging back and forth between two old things that were already there, but a drive into a brand new dimension.