A giant airplane appeared, heading straight toward the window through which Earl watched. It grew larger. For a brief second he looked into its control cabin and saw its pilot and co-pilot. They were human, but their faces were harsh and cruel, their eyes cold and inhuman. In the next instant they were gone. "That is a typical scene on--the other Earth," the voice of the Cyberene explained. The scene of the desolate city vanished. In its place appeared another scene. A city under construction. Giant building machines were placing it together, and the parts that were completed were even more beautiful than had been that other city. Earl, from his vantage point, seemed to drop closer and drift over the scene of construction to a part that was inhabited. He saw the people below. They wore no clothes and didn't seem to mind. Each appeared to be intent on going somewhere. None of them were talking or paying any attention to one another. Their expressions were blank, their eyes vacant. The vantage point followed one of them. Shortly the man being followed turned into an archway, up an incline, and into a large hall. He went through a door into the room filled with cell-like vats. In each transparent vat Earl saw a human embryo, alive and growing. He "followed" the man through this place to another, where children were playing with psychological toys designed to increase mechanical and scientific aptitudes. "This, too, is a typical scene on--this Earth," the Cyberene said. The scene vanished. Once again Earl looked into the video eyes of the Brain. "They are both Earth in the year 3042," the Cyberene said, "but not the _same_ Earth. In 1980 there was a split. Earth followed two independent futures. The first, filled with wars and eternal carnage, ever more perfect weapons of destruction, developed from _one_ decision you made. The second, my world, filled with perpetual peace and happiness, developed from the alternative decision. _You_ created these two futures." "I?" Earl said. "You must be crazy. How?" "In the first you discovered the vital nerve fluid that makes me possible. You thought you were God. You thought you could see a future in which I would work the human race harm. You suppressed your discovery by the simple process of giving a negative lab report on the substance. In the second world--_my_ world--you did as you were supposed to do. You announced your discovery. _I_ came into being." "You mean to say _my actions_ caused the whole planet to split into two identical worlds?"