I just watched this interesting video talking about temporal paradoxes and how we can travel forward but not back because of the relativity of time. I really like the theory and it makes sense to me. How can we go back in time (unless it is just for observation and we are unable to participate) when it would prevent us from having to have to go back in the first place so it would never have occurred. That makes not sense to me. However, the past being able to see the future because the past would not be able to exact any change in it (other then maybe getting the lottery numbers and such to take back with them).