All other streams of philosophies can be merged in one as subsets or partial views of reality. The nondual is not separate from dual. It is just that, that which is dual is merely an appearance. Nondual is the substratum on which all duality appears in various illusory forms. Reading and discussion on the English translation of the Mandukya Karika by Gaudapada, which is a commentary on the Mandukya Upanishad.