The future will always be the same. I'll set up an example. Let's say someone is trying to time travel back to fix something bad in the future. You are there and have the option to help him. Would you? The reasonable answer is no, because now whatever you do is what your past self will do at this time when you are your future self. The time traveler will create the bad thing that is happening in the future. tl;dr: A time traveler going back in time to fix something will do nothing new to the future your in.