The NY Times has an article about how Political Scientists can’t do better than random when attempting to predict outcomes (e.g. the fall of the Soviet Union, whether an official is re-elected, whether a nation will join NATO). The author cites a gem from Karl Popper:
Long-term prophecies can be derived from scientific conditional predictions only if they apply to systems which can be described as well-isolated, stationary, and recurrent. These systems are very rare in nature; and modern society is not one of them.
Update: One reader, a foodie (wow, I have more than 3 readers now!) points out that the study was flawed and makes some good points. Check out his comment.