Imagine ... the act of creation. Assume that out of the chaos and fire of the Big Bang came only one electron. This electron moves forward in time for billions and billions of years until it arrives at another cataclysmic event - the end of time, or Doomsday. This shattering experience, in turn, reverses the direction of the electron and sends it back in time. When this same electron arrives back at the Big Bang, its direction is reversed once again. The electron is not splitting up into many electrons; it is the same electron that zigzags back and forth like a Ping Pong ball between the Big Bang and Doomsday. Now, anyone sitting between the Big Bang and Doomsday in the twentieth century will notice a large number of electrons and antielectrons. In fact, we can assume that the electron has traveled back and forth enough times to create the sum total of electrons in the universe. (Of course, an object traveling back and forth in space cannot create more than one copy of itself. However, an object going back and forth in time can indeed have copies of itself.... In principle, this effect of going backward and forward in time can be repeated an arbitrary number of times, thereby creating an infinite number of carbon copies in the present.)

If this theory is true, it means that the electrons in our bodies are the same electron, the only difference being that my electrons are, say, billions of years older than your electrons. If this theory is correct, it also helps to explain a fundamental principle of chemistry: that all electrons are alike. (A modern-day version of this theory would be to have a one-string universe.)