“But I had a…a friend twenty thousand years ago. Another robot. Not like myself. He could not be mistaken for a human being, but it was he who had the mental powers and it was through him that I gained mine. “It seemed to him that there should be a still more general rule than any of the Three Laws. He called it the Zeroth Law, since zero comes before one. It is: “ ‘Zero. A robot may not injure humanity or, through inaction, allow humanity to come to harm.’
