 Everything from the change of seasons to the movement of planets and alternation of emotions can be understood in terms of yin and yang. The pair gives us a way to make sense of the constructive and deconstructive aspects involved in any change. We can understand any change or any state as involving contrastive elements that alternate with one another during change. These two complementary and oppositional principles of yin and yang (not forces or substances but something more like causally efficacious qualities or categories) explain the movement and change of things in the world. In most early Chinese texts, yin and yang are given a balanced priority. They are equally responsible for the emergence of things, each governs half of the year, the day, and growth. The Chunqiu Fanlu makes the unusual move of elevating the position of yang, making it responsible for a greater amount, of more potency, and thus ultimately higher value.