Even if a particle could travel backward in time, information could not. Retrocausality will be replaced by something more sophisticated. There are no perfect symmetries, there is no pure randomness everything is an approximation of something else. Information may appear in a digital form but meaning never does. Spacetime is built up from approximations, not discrete ones and zeros, and the only constant may be ratios. Quantum entanglement and geometry; if we think of a particle as being at one pole of an expanding sphere that is not perfectly symmetrical, this surface would be "rippling" like the surface of the ocean (in the audio world this is called dithering), at the other pole is the entangled particle's pair and it is a property of the sphere that gives the illusion of connectivity. This is not a physical geometry, it is a computational geometry. Is spacetime a product of entanglement? Renate Loll believes that time is not perfectly symmetrical. Her computer models require causality. Possibly some form of quantum random walk in state space. If a photon is emitted by an electron inside of a clock on Earth and it travels to a clock four light years away, time stops for the clock on Earth and time jumps forward eight years for the distant clock also, the electron that will capture the photon becomes infinitely large relative to the photon but the electron that emitted it does not become infinitely small therefore, time is not perfectly symmetrical.
