In the March 09 Scientific American there is an article ("Impossible Inferences"
about incompleteness theorems and claims that it is impossible for an entity inside the universe to learn everything about how the universe works.
It also talks about predicting the future and presents the question:
"Will your answer to this question not be 'yes'?"
It claims that nobody can correctly answer the question and therefore the future is unpredictable.
I disagree. I think that it is impossible to truthfully answer the question with a 'yes' or a 'no' but that is not equivalent to being unable to predict the future. If you simply don't answer it, that is predictable.