I've talked about my disappointment with many time travel stories because they don't address basic questions about momentum and try to claim that people can "get away" with time travelling so long as they don't change anything, when quantum mechanics requires them to change everything (at least on the scale of the very small). Here is my last objection to the way people write time travel stories, and also how they read them. I have read a number of essays and blog entries where people dismiss a time travel story as ridiculous because of the way that they "know" causation works, when in fact we are all ignorant of how causation would work in the presence of time travel. There may be good reasons to doubt time travel is possible, but this certainly isn't one of them.
