Man inhabits, for his own convenience, a homemade universe within the greater alien world of external matter and his own irrationality. Out of the illimitable blackness of the world the light of his customary thinking scoops, as it were, a little illuminated cave — a tunnel of brightness, in which, from the brink of consciousness to its death, he lives, moves, and has his being. …. We ignore the outer darkness; or if we cannot ignore it, if it presses too insistently upon us, we disapprove of being afraid.