In a weird way, the fact that there are no time travelers around is troubling. Does this mean that the earth ceased to exist before anyone figured out how to travel back in time, or is backwards time travel simply impossible? It seems, intuitively, that the second option is the more logical option – Occam ’s razor – but is it? If we are this close to understanding time, isn’t it more logical – and simpler – to expect time travel to eventually come to pass? If I were told to invent a time machine in a week it would be impossibly unlikely, but if I had until the end of time it would be as simple as walking to the moon. All I would need to walk to the moon is time, a way to get there, and a promise that it is possible. All I would need to invent a time machine is time, a way to get there, and a promise that it’s possible. Is the fact that there are no time travelers evidence that the human race didn’t make it, or evidence that backwards time travel is impossible?