(If you’ve never heard of the grandfather paradox, head over to the Times piece now. I avoid describing it here so as not to taint what follows.)
One thing that irks me when people talk about the grandfather paradox: It’s not so much that you can’t go back and kill your grandfather; it’s that you always already didn’t do so (to co-opt a suddenly non-bogus phrase from the post-structuralists).
So the same goes for the LHC. I think the prediction on the table isn’t that something will happen to keep it from working; it’s that something already has (or, like, “already will have”—our verb tenses don’t do justice to the physics).
I have a pet peeve around the issue because this kind of not-quite-right summation kept me from really understanding the grandfather paradox for years.