Is Game Theory a scientific theory?

A wonderful quote about the nature of Game Theory

Game theory is no doubt wonderful for telling stories. However, it flunks the main test of any scientific theory: The ability to make empirically testable predictions. In most real-life situations, many different outcomes -- from full cooperation to near-disastrous conflict -- are consistent with the game-theory version of rationality. 

by Michael Mandel, on Kahneman and Smith 2002 Nobel Prize in Economics. 

Interestingly enough, as of Dec. 1st 2008, google finds 3 million pages about “game theory”, half of them containing criticisms about it. Mostly about the abuse of the “rationality assumption” but also about the confusion about using it as a normative theory (i.e. a theory of how humans must behave) instead of descriptive picture (i.e. a mathematical way to explain how humans could behave). More on normative vs. descriptive analysis in the wikipedia.