Paycheck/Fridge

Fridge Logic

 * The time scope prophesies are only self-fulfilling if everyone critically fails at foresight. Of course herding the sick together causes an epidemic! If you go to war to prevent a war, you're still at fucking war! Gah!
 * Also contradicted by the movie's basic premise. Jennings is implied to have looked into the future and, each time he saw himself get killed, arranged for his future self to be carrying a gadget which will get him out of the situation. Why can't whoever uses the time scope do the same with policies that create wars and plague?
 * Fridge Brilliance: Jenning's job is to reverse engineer existing technology and improve on it. This means that he's really good an analyzing all aspects of something, while politicians might not be.
 * Ask an epidemiologist which is more likely to spread a cold; twenty people in a crowd that has five people with colds distributed at random, or those same five people identified and isolated in a corner away from everyone else?
 * (To OP) The reason why the people are isolated, and why a war happens, is because the politicians in control of the time scope only saw that the epidemic happened, and that the war happened, but they did not know how it happened, so... Also, the reason why Jennings manages to make all those changes only means that changes can be made to the future, but it is not easy to do it. Making small changes that affect the outcome of one, perhaps two or three, people, is relatively easy, but things that affect entire countries? Not so easy. It is basically the inverse of psycohistory.