"The cow is there," said Ansell, lighting a match and holding it out over the carpet. No one spoke. He waited till the end of the match fell off. Then he said again, "She is there, the cow. There, now." "You have not proved it," said a voice. "I have proved it to myself." "I have proved to myself that she isn't," said the voice. "The cow is not there." Ansell frowned and lit another match.