Originally Posted by NichePay - StuartD

That's the thing... it's virtually IMPOSSIBLE to go back in time and simply breath the air without changing things in the future.

The further back you go, the more impact you have simply by being there. If you kill a bug, if you step on a plant, if you say one word to someone, if you have ANY kind of influence at all, it will have an impact on the future.

So to say that you go back in time, you can't have an effect on something that will happen in the future... that's totally bogus. Sure you might not be able to kill your father to stop your birth, but perhaps you'll stop a bird from eating a worm if you step on the worm on the side walk. Just because it didn't inconvenience your future, doesn't mean you didn't change it.