Thoughts on Doctor Who

My mind refuses to focus on any one thing at any one time. So here I go trying to take a shower and this thought pops into my head. In Doctor Who, the Doctor is always saying that something was not supposed to happen Ina particular way and so he acts to change it back. He also talks about fixed points in time that cannot be changed. If he is convinced enough about history following a certain line then isn't it safe to say that the moments the Doctor goes back to change to his "correct" view of history, happened just as they should. It is the Doctor's added influence that provided the expected historical outcome.