Wikipedia wrote:Although time travel has been a common plot device in fiction since the 19th century, and one-way travel into the future is arguably possible given the phenomenon of time dilation based on velocity in the theory of special relativity (exemplified by the twin paradox), as well as gravitational time dilation in the theory of general relativity, it is currently unknown whether the laws of physics would allow backwards time travel.

I used to take it for fact that travel backwards in time was impossible, because this would create a paradox. In fact, my logic was this. If paradox, then fiction (I developed this idea to fix a lot of paradoxes popping up in books; the idea is that these paradoxes exist because the book makes a statement that could not possibly be true in the real world, such as: magic exists). So I took the idea of backwards time travel and I branded it as impossible.

Well, Wikipedia, which is usually well known for its clear and concise statements, obviously disagrees with me. So I was wondering, is there a property of logic (or something) that states that paradoxes are proofs of impossibility?