Not Two, Not One
The two is representative of a dualistic worldview. The one is
representative of a non-dualistic worldview. Not two, not one states
that both are inadequate models of the world. The world is neither two
nor one; both two and one; two and not one; and not two and one.
References
Nagatomo, Shigenori. 2024. “Japanese Zen Buddhist Philosophy.” In The Stanford Encyclopedia of Philosophy, edited by Edward N. Zalta and Uri Nodelman, Fall 2024. Metaphysics Research Lab, Stanford University. https://plato.stanford.edu/archives/fall2024/entries/japanese-zen/.