Thomas Kuhn's Structure of Scientific Revolutions described the social cycle through which science advances, one stage of which is the paradigm shift for which he is famous.
Curtis Brown's notes provide an excellent summary of the cycle and Kuhn's notion of incommensurability which explains how social behavior creates the cycle:
In The Structure of Scientific Revolutions, especially chapter IX, Kuhn appears to suggest that each "paradigm" carries with it a set of evaluative criteria on which it scores well, so that there are no neutral criteria that will decide which theory is best.
"In learning a paradigm the scientist acquires theory, methods, and standards together, usually in an inextricable mixture. . . . each paradigm will be shown to satisfy more or less the criteria that it dictates for itself and to fall short of those dictated by its opponent"
In later writing, notably "Values, Objectivity, and Theory Choice," Kuhn takes what seems to be a more moderate view (though he claims that this is what he meant all along), holding that there are general criteria for theory choice on which nearly everyone can agree -- things like simplicity, scope, coherence with existing theory, etc. But he also argues that proponents of different theories may well interpret these criteria differently.