  We introduce a quantum mechanical model of time travel which includes two
figurative beam splitters in order to induce feedback to earlier times. This
leads to a unique solution to the paradox where one could kill one's
grandfather in that once the future has unfolded, it cannot change the past,
and so the past becomes deterministic. On the other hand, looking forwards
towards the future is completely probabilistic. This resolves the classical
paradox in a philosophically satisfying manner.
