Yin and Yang

Yang and yin are in some ways parallel to the Buddhist view of form and emptiness, of which the Heart Sutra says, “That which is form is just that which is emptiness and that which is emptiness is just that which is form. - Alan Watts

The yin-yang principle is not, therefore, what we would ordinarily call a dualism, but rather an explicit duality expressing an implicit unity. - Alan Watts