Duality exists because our minds capture our attention and direct it outward into thoughts, ideas and pleasure of the ego.
In our awareness the knower reveals all things which are true and manifested in existence. The knower is the infinite consciousness of which we are one with. No division exists within the knower, it reveals what is to us.
The knower is the only one that can reveal to us what is true for us. Outside our inner knower exists only that which cannot be known, because it exists in the realm of the unreal.