Originally Posted by Syn
Face it, the effects of time travel in Back to the Future have directly conflicted with each other. Just accept any paradoxes as is and don't try to analyze it.
Even in Episode 4 we have a 'Doc' that never invented time travel yet there's still a time machine. And we still have a 'Doc' that never created time travel yet there's still a Clayton Ravine.
Just enjoy the ride and throw logic out the window.
Yet there's still?
Perhaps you should have tried paying more attention to the third movie. It was the LACK of time travel that resulted in the name Clayton Ravine. Without any time travel 1885 would have reverted to pre-Brown/McFly interference and poor Clara would have died.