chaotic is good, but I don't personally think you could ever determine the state of the world in the future. To do that you would have to factor in human behavior which is entirely to complex to ever account for.
The main reason the world would not be deterministic is because of Heisenberg's Law (or whatever it's called), which states that at some level there is true, utter randomness.
However, the human brain isn't really much more than a bunch of particular molecules arranged in a specific way with lots of little electrical impulses being stored and shot around - at least in my worldview. Assuming you can capture all the physical information about a person's brain and what they are seeing around them, you can problably calculate their next frame of thought. ymmv.