Truth

All that you, with your little brain, can not think, say, define, translate, write... that is, Nothing.
Nothing thinkable, verbalizable, questionable, translatable.
For this reason nobody wants the truth: it is neither teachable nor salable.

Truth school lesson.

Student: Who were you before you were born? That is, who are you?
Liar (School Teacher): Simply myself.
Honest student: Don't know. I can't express who I really am.