dividing problems into theory and empiricism, specifying your theory exactly then looking for evidence to either confirm or deny the theory, or finding evidence to later form an exact theory.

The main advantage of having this feedback loop is that the deviations from the search for "truth" are self-correcting. Less-than-rational thinking may slow you down, but it will still let you get to a better model of the world eventually. On the other hand, even the most rational thinking without the feedback inevitably results in very inaccurate models.

Basically, the scientific method alone completely trumps rationality alone, though of course you get best results when combining the two.