The term 'Half of a Theoretical Duality' can be summarized as the concept of yin and yang. This is an ancient Chinese philosophy that states that two opposite forces, such as light and dark, are interconnected and interdependent in the natural world. The term 'yang' is used to refer to the masculine, active, and light side of the duality, while 'yin' is used to refer to the feminine, passive, and dark side. Together, these two forces form a balance that is essential for harmony and balance in the universe.