If something cannot be known, then there is no point in speaking about such a thing. Meaningful existence of any entity depends on knowability. And by knowability at os, i don't mean noability just by you or me. It must be it must reveal itself to awareness somewhere in some way. Even if it does not, the possibility must be there that it can be known.
Swami Sarvapriyananda teaches one of the shortest and most profound upanishads accompanied by Gaudapada's Karika. This lecture covers Mantra 2.