The Real Rules for Time Travelers

This article fried my brain a little:

Some of our understanding of time is based on logic and the known laws of physics, but some of it is based purely on convenience and reasonable-sounding assumptions. We think that the ability to uniquely determine the future from knowledge of our present state is important, but the real world might end up having other ideas. If physicists discover that closed timelike curves really can exist, we will have to dramatically rethink the way we understand time. In that case, the universe could not be nicely divided into a series of separate “moments” of time.