"We speak still of "sunrise" and "sunset." We do so as if the Copernican model of the solar system had not replaced, ineradicably, the Ptolemaic. Vacant metaphors, eroded figures of speech, inhabit our vocabulary and grammar. They are caught, tenaciously, in the scaffolding and recesses of our common parlance. There they rattle about like old rags or ghosts in the attic."