I have a question that bugs me a little, I've explained it as best I can in my own mind but it still somewhat irritates me. So at the end of the DT book 7, we know that Roland is caught in a loop and is forced to repeat his journey to the Tower again and again, we have no idea how any times he has already completed this journey however I feel I am safe in assuming it has been a lot. Philosophically speaking I think I understand the reason behind this, there's lots of theories of course - relating to Roland making mistakes that need to be fixed along the way, or perhaps him never being supposed to reach the Tower at all but rather find greater substance and meaning in his experiences along the way etc.
My question is simply this: Roland being sent back each time he reaches the tower causes a lot of problems in the story. Primarily we are told time in the keystone world can not be changed, you can not move back in time within the keystone world, once something occurs there then it has happened and that's all she sold! However every time Roland is sent back time in the keystone world automatically resets itself. An other interesting problem I find from this same question is the fact that every time the Tower sends Roland back it is threatening it's own(and by extension the Multiverses' existence, as perhaps this time he may not succeed in stopping the King's men at Blue Haven?
I love the Dark tower, and as I originally said I have my own theory's which justify these issues satisfactorily to myself! I simply want to see what other people make of these problems, it's always fun to debate!
P.S Sorry for the spoiler tag if it bugged people, but I talk about so many spoiler things here, it's just better to be safe than sorry - as I likely would have murdered someone who spoiled the series on me back in the day