As such there is a continual ‘time-line’ of the same electron. It is, initially e2, it then collides with the positron and, in the guise of the positron goes backwards in time to become the original electron e1 that was caused by the first collision. It then changes time direction by becoming an electron again and carries forward in time. As Davies says:
“In its normal, electron phase, (e2) emits a photon and bounces back in time, then absorbs a photon and rebounds back to the future again. An observer located in time would see two electrons and a positron. But Feynman says this is really only one particle seen three times”.[i]
From this Feynman postulated that all the electrons in the universe are just this one particle bouncing backwards and forwards in time. In other words, as Paul Davies says:
“You and I, the Earth, the sun, the Milky Way and all other galaxies are composed of just one electron (and one photon and one neutron too) seen sqillions of times over. This offers a neat explanation as to why all electrons appear to be identical”.
This will also predict that the universe must be made up of equal amounts of matter and anti-matter, because every ‘zig’ must have a ‘zag’."