No Events on Closed Causal Curves

We introduce the Causal Compatibility Conjecture for Events, Trees, Histories (ETH) approach to Quantum Theory (QT) in semi-classical setting. then prove that under assumptions of conjecture, points on closed causal curves are physically indistinguishable context ETH QT and thus conjecture implies a compatibility structures even presence curves. As consequence this result there is no observation could be made by an observer tell any two curve apart. conclude have physical significance QT. This indication time travel will not possible full quantum theory gravity forever remain fantasy.