Iamdan, as you stated you cannot know both the exact momentum and position of an object at the same time making it impossible to determine the future, there is no way to circumvent this problem. Even if you knew the momentum and position of everything in the universe, how exactly would you be able to build a computer that could handle all this information and predict the future at a faster rate than the time itself? And even if you somehow would be able to build this computer it wouldn't work anyway because some things that happen are truly random, such as radioactive decay, which also means nothing is fated, but random. Ever heard about the Conservation of energy?