You have a soul mate, VadeRetro, in the great French mathematician Marquis Pierre-Simon de Laplace (1749–1827):
“Given for one instant an intelligence which could comprehend all the forces by which nature is animated and the respective positions of the beings which compose it, if moreover this intelligence were vast enough to submit these data to analysis … to it nothing would be uncertain, and the future as the past would be present to its eyes.”And so, "all you have to know is everthing right now, and all the rules." Do you know "everything right now," and "all the rules?"
It really sounds to me like Laplace is divinizing man here (actually one supposes himself); for he is effectively placing him on the throne of God, who sees and knows all. But how could a man possibly know all the contingencies that bear on any given problem or circumstance? He doesn't stand outside the universe, so to view it entire and in detail, from some Archimedean point outside. He is part and participant in it. Even if you think you know ALL the physical laws (dubious; I imagine there may be some we don't even know about yet), you do not know and cannot know all the details of anything you observe.
Neither I nor Laplace claimed to be in possession of such omniscience, so to that extent it's theoretical. However, it also applies to the dreaded "closed systems" to the extent you can find one.
However, it has turned out that there are real limits to how deterministically the universe will behave. The archetypal illustration is a certain apocryphal half-dead German cat.