3 Days, 9 Months, 27 Years (The Time Traveler's Passport)

by John Scalzi

If time travel cannot affect our own history, and every trip back branches a new reality, and those new realities have no effect on our own, then as a practical matter, from our point of view, there are no consequences for intruding into this new reality. Yes, anything one of our clients did would affect them, but that was a them problem, and also, from a philosophical point of view, anything that happened in that reality was meant to happen in that reality, otherwise it would not have happened, or could not have happened.

The politicians, activists, and philosophers asked these scientists how they would feel if people from another reality time-traveled to ours and changed the course of our own history. The answer was: It probably hasn’t happened, because our history shows no evidence of temporal visitation. But if it was going to happen, then it already happened. If it happened, we don’t know that it happened. If we don’t know that it happened, then the impact of it happening must have 13been so negligible that it doesn’t matter that it happened. But it probably hasn’t happened. Some reality had to be the first to figure out time travel. It was probably ours.

I told him the answer was too complicated to explain in the time he had left before his exit, which was probably true and a convenient way to cover my own ignorance.