In the Christian inner tradition, this path of the intense fusion of two beloveds into one abler soul has sometimes been called "the Fifth Way." The term itself is of fairly recent vintage, coined by Boris Mouravieff in imitation of Gurdjieff's Fourth Way, although the teaching it conveys is ancient. If the Fourth Way is the way of consciousness, the Fifth Way is the way of radical meltdown through total self-abandonment in love.
— Cynthia Bourgeault, Love Is Stronger than Death