According to J.C. Cooper in An Illustrated Encyclpaedia of Traditional Symbols, numbers have represented for many traditions and cultures an organizing principle from which all things originate and are the basis for the underlying harmony of the universe. The number two is a symbol for both balance and the passage of time.
The Chinese system of numerology is based on the number two as it represents the dual nature of the cosmic forces yin (female) and yang (male). Taoists believe yin and yang are forces which are in opposition and yet complementary. An even number, two is terrestrial and mutable. Two is the Buddhist symbol of duality of samsara; female and male, theory and practice, wisdom and method. The number two in Taoist belief is The K’ua or the Two Determinates, the yin and yang.
In Roman myth, Janus (son of Apollo) is a two headed god who looks in both directions and to whom all gateways are sacred. Janus is associated with beginnings; sunrise, sunset, and each season. To this day, January 1 is a day to look both forward and back and to reflect on the new year.
Pythagoras, who believed “everything is disposed according to numbers”, stated that two is the first number of the female principle.
Hindu belief states that numbers are the primary substance of the universe. Two represents duality or the shakta-shakti.
Simply stated, the Kabbalah is a complex system of symbols used to understand the spiritual dimensions of the universe. Each letter of the Hebrew alphabet has a number associated with it. The Kabbalistic sefirah, Hokhmah, symbolizes wisdom. Two is the Hebrew symbol of life force.
Cooper, J.C., An Illustrated Encyclpaedia of Traditional Symbols, Thames & Hudson Inc, New York, 1995