If I read, I change. If I eat, I change. If I sleep, work out, travel, or do virtually anything, I change. Yet I myself have only an indirect effect on how it is that I change by putting myself into the environment that forms me. And as much as I might like to think that sitting in a black box I can learn just as much as through interaction, I am starting to have to come to terms with the simple idea that my uniqueness is only defined by that which surrounds me. And, consequently, it would simply be impossible for me to think of anything that I am not exposed to.
Moreover, as I have poor memory, if I segregate myself from the world for a period of time, I start to disappear. If I am with people with whom there is no discussion, I start to fade out. I am still here – I know it, the people around me seem to know it, but nevertheless, the only proof that I have is the disturbance my presence might introduce.
Then we can take this to extremes… suppose there is a world where people become transparent ghosts if they close their eyes and stand there for long enough. Nobody sees them, and they see nobody, and so long as they do not open their eyes, they can move anywhere they please. Yet as soon as they begin to see, they aqcuire substance and are consequently grounded – lose their lucidity. Sleep?