A beam or pillar can be used to batter down a city wall, but it is no good for stopping up a little hole - this refers to a difference in function. Thoroughbreds like Qiji and Hualiu could gallop a thousand li in one day, but when it came to catching rats they were no match for the wildcat or the weasel - this refers to a difference in skill. The horned owl catches fleas at night and can spot the tip of a hair, but when daylight comes, no matter how wide it opens its eyes, it cannot see a mound or a hill - this refers to a difference in nature. Now do you say, that you are going to make Right your master and do away with Wrong, or make Order your master and do away with Disorder? If you do, then you have not understood the principle of heaven and earth or the nature of the ten thousand things. This is like saying that you are going to make Heaven your master and do away with Earth, or make Yin your master and do away with Yang. Obviously it is impossible.
Zhuangzi, The Complete Works of Chuang Tzu
duality, good-and-bad, interdependence, nonduality, opposites, right-and-wrong, taoism, unity, wholeness, yang-and-yin, yin-and-yang