"I don't know," he said. "Perhaps it can't be done. Perhaps it would involve a parallel time stream, if there is such a thing. All I know is that I must try. If I can, she might still consent to be my wife later, if the difference in our ages isn't too great. That would be up to her." "I don't see how you even know where to start on such a project," I confessed. "The chances are slim," he admitted, "but I have some hope. The only actual time reversal we know, scientifically, is at the sub-atomic level. The theory was advanced by Feynman that annihilation of an electron-positron pair upon contact might be, not actual annihilation, but a 'time reversal' of the electron. The emission of a photon of energy, in such cases, is powerful enough to cause a recoil in time, and the positron is merely the electron traveling backward through time after the energy explosion." I looked extremely blank. "Look," said Wyn, taking up a pencil. He drew a big "Z" on a piece of scrap paper, labelling the two arms "E" and the connecting line "P". The angles he marked "A" and "B:" * * * * * "The flow of Time is from left to right," he explained. "At left is the past, at right the future. This electron, E, is moving normally along at the top of the diagram when it runs into an energy explosion at A. It reverses itself, going back through time as the positron, P, until it hits another energy explosion at B. Then it is reversed again into the right time direction, continuing as the electron E, at the bottom. You follow the line, as the pencil point does in making the Z, and it's a single body." E --------- /A / / /P / / / E B --------- "But," and he drew a vertical line through the Z, "we move always forward in time. To us, the energy explosion at B happens before the one at A. Suddenly at B, a positron and an electron are created out of nothing. The electron at the top apparently has nothing to do with either of them. But the positron moves along and collides with it at A, leaving nothing there again--except, once more, an apparently unrelated electron, the one at the bottom of the diagram." "But you're saying the same thing can exist in three places at once," I objected. "Exactly, but in one of those places, it's traveling backward in time. So, if Summer's time reversal occurred or will occur after birth, she may be existing somewhere else, as a younger girl, right now; besides being here in the house with us." "Your example is, as you say, at the atomic level," I said. "How can you transfer that into terms of human beings?" "The only thing I know to do," he said, "is to create an energy explosion which I know won't hurt Summer physically, but may reverse her back to a normal direction. It would be like the energy explosion that meets the positron at B and forces it to continue existence as an electron."