With all the discussion of Indetermancy in another thread reminded me of this thought experiment.
Imagine a demon that has full knowledge of the present. The location/energy of every molecule everywhere in existance.
Now, as the scenario plays out, this demon can now succesfully predict the future using Newton's laws to calculate the future position/energy of all the molecules, and hence now knows the full future of the universe, from when/where the next hurricane will show up, to when stars will super-nova.
So I guess the question is, is this logical valid? If a demon did know everything about the present, could they could fully predict the future?