Is duality all?

Is duality all?

Everything seems to come in packs of two. Two brain halves, as above so below….what is life beyond duality like?

If someone knows ,please contact me, and tell me all about it. For the time being I guess black is needed to perceive white, a mountain comes with a valley, no night without a day. 

Non-duality is hard to talk about? Who has really experienced it and how to talk about it from a dual existence, intellectually?