Quora Answer: Is Taoism a monist or dualist theory?

Neither, it is nondual & nonmonist with the idea of Void (Wu Ji) Wuji (philosophy) based on  無 – Wiktionary

A friend of mine Rodney H. Swearengin suggested we should call it non-cardinal and we note that zero is the only non-cardinal number.

Non-cardinal is an alternative beyond all the possible logical alternatives. So for instance zero is a non-cardinal alternative to all the numbers.

Void is normally associated with empty spacetime, and thus with the nondual aspect of nature and extensionality as such.

It is distinguished from Emptiness of Buddhism which is defined as something other than the tetralemma (A, ~A, Both, Neither) i.e. something other than the logical possibilities.

When Buddhism first came to China the Chinese scholars thought that by Emptiness the Buddhists in India mean the same thing as they meant by Void. But eventually they realized that the Buddhist Emptiness was different from the Void. Eventually they developed very sophisticated philosophies which dealt with both Emptiness and Void, i.e. internal and external non-cardinality. The best example of this is Hua Yen Buddhism of Fa Tsang, which reinterpreted emptiness as interpenetration. Fa Tsang talks about both interpenetration and interinclusion, i.e. mass-like and set-like ways of approaching other things, which should be contrast with intrapenetration and intrainclusion to cover all the possibilities.

Basically these four cover both set and mass approaches to what is external and internal. Note that emptiness which is internal is associated with inter-x and void which is external is associated with intra-x. In other words there is mirroring between emptiness and void.

We see in the poetry of Stonehouse (Shiwu) the zen taoist hermit lines of poetry where one line is empty and the next line is void and then the next line is empty etc.Thus in the Chinese tradition they become very sophisticated in balancing and distinguishing these two types of non-cardinality both internal and external both mass-like and set-like whose exhausted possibilities (inter/intra//in/exclusion) points to the possibility of a deeper nonduality beyond the difference between emptiness and void.