Our conscious experience of the world is systematically externalized because the brain constantly creates the experience that I am present in a world outside my brain. Everything we know about the human brain today indicates that the experience of being outside the brain, and not in a tunnel, is brought about by neural systems buried deep inside the brain. Of course, an external world does exist, and knowledge and action do causally connect us to it—but the conscious experience of knowing, acting, and being connected is an exclusively internal affair.
