Non-duality

Before thinking, judging, rationalizing, using brain as a tool; what is it that enables brain to do so? Does the ability to perceive exist because of brain or is it the presence of That that lets your brain function? Certainly, That came first, then the brain could think. What is that That? Is that That the same That which permeates all the beings, matter, and every manifestation that there is? 'I' - a pointer to That 'my' brain can perceive - am That, and That is 'I'. There is no separate me, I, we, they, or you. There is That. Just That. This is non dualism; oneness. Advaita !