The brain
The relationship between consciousness and the brain is a form of double-ended causality. We might say that we are limited by our brains, but we could just as well say that the brain is a representation of our limitations. Contrary to popular belief, the brain does not create experiences—at most, it receives them, and perhaps not even that. The eye doesn’t create light, nor the ear sound, and so too the brain does not create consciousness, meaning, experience or the soul. These things already existed before the brain came into being.
Where is the brain? It seems to be inside the world. But then, where is the world? The world seems to be inside the brain, since the brain is allegedly what mediates our experience of it. So then, the brain is inside itself. This is a useful meditation technique: one sits down and closes one’s eyes, then attempts to locate one’s brain in the world, and reminds oneself that the brain is inside itself. Meditating on this paradox can reveal a way out of the materialist way of thinking and into reality. Of course the brain does not really exist in the world, and the world is not really taking place “inside the brain”. As for how these things are connected, that’s unclear.