Opposites

I think that the Opposites presented in the Daodejing have a lot to do with the concept of an inherent nothingness in the world.  Some of the most obvious opposites exist solely because of a lack of something.  The Daodejing referencing the spokes on a wheel helps to illustrate how something like empty space is an opposite and brings purpose to make the wheel functional.  The wheel would most likely have less optimal functionality if the spokes and empty space didn't exist.  Light and dark only exist as opposites because dark is the absence of light (I equate darkness to a form of nothingness).  Both light and dark are contingent on one another to exist/survive and I feel that is the essence of opposites.  The opposites also juxtapose each other, further enhancing each one's features (the light looks lighter and the dark looks darker).