The notion of duality, which must be distinguished from dualism, is common to every human culture. It finds a particular expression in the concept of the couple, an idea understood as a generating agency not only in the field of animal physiology but also in numerical and metaphysical symbology (as, for example, in Pythagorean speculation). According to this, the One and the Two, as generating principles, are perceived as masculine and feminine. The kind of duality expressed by the generating couple need not be viewed as dualistic in itself, but the shift from duality to dualism is obvious when the constituent elements (the One and the Two, male and female) are understood as principles that are, in effect, principal: that is, when their mutual relationship is responsible for the first origins of the world and of human beings and, at the same time, is one characterized...