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
...more
