The Law of three is the most significant abstract principle of life and living systems. In has been recognised as such as a informing pattern of a wide range of metaphysical systems.
It was introduced to the west by George Gurdjieff and later refined by one of his students (in my opinion the most significant of them), John G Bennett who extended beyond the triad (3), heptad (7) and enneagram (9) to a whole new field he called Systematics.
Every system (of the 3 laws) is a part of a larger system and is itself a whole to contained systems ("multiordinality")
It is interesting that in searching for a better label for the 3 laws than Bennett's that the LO3 expresses itself in the hunt for a label that "reconciles" its dualistic nature of being & becoming.
The law of three is the name Gurdjieff gave to a 3 term system; that is any system that has 3 terms or nodes. Each of the terms of the triadic has a particular unique character, often called a force. Together these 3 forces combine to create a larger whole or holon.