And another thing: I do not accept the
a priori supposition that a phenomenon which raises causality paradoxes is thereby inherently impossible. That's basically an extrapolation of the Fermi Paradox into quantum physics. As I've mentioned in other contexts, I haven't any problem with the unexplained or even with the inexplicable (assuming there is such a thing). My attitude is this: if it appears like a paradox to our perception, it is probably perfectly consistent with reality in a higher dimension (whether actual or theoretic and no matter how far beyond our comprehension).
Maybe the key is to just do what we can do in practice without regard to the theoretic paradoxes. Let God deal with the hypothetical causality violations.. =)
And another thing: I do not accept the a priori supposition that a phenomenon which raises causality paradoxes is thereby inherently impossible. Nor do I. If I am presented with conclusive evidence of causality violation, I will accept it. However, everything I've seen suggests to me that causality is respected in the physical universe.
When I observe that special relativity says that travelling faster than light is equivalent to travelling backwards through time, I am not making any statement about the impossibility of travelling either faster than light or backwards in time. It is merely a mathematical observation about special relativity, and a correct one.