"A person doesn't seem to know it [the Ultimate reality] only because he is used to seeing things dualistically, where he as subject holds out and looks at an object, either mental or physical, and feels that, yes, he sees that object very clearly, with 'he' and 'that object' being two different things altogether. He, as subject, then automatically assumes that he can also see Brahman [the Ultimate reality] in the same way, as an object out there to look at and grasp. It thus seems that he, the grasper, should be able to get Brahman, the grasped. But Brahman won't split into getter and got. In all of reality there is only one, without a second, and yet out of habit the person tries to make It two, to split It so as to finally grab It and exclaim, 'Aha, I've got it!' He tries to make it an experience to be grasped amongst other experiences. But Brahman is not a particular experience, being one without a second, and so he is left grasping at ghosts and clutching at smoke."
- Ken Wilber Eye to Eye