Murray Rothbard on the upward march of human progress

[H]istorians of economic thought, similar to historians of other disciplines, have habitually treated the development of science as a linear and upward march into the truth.  Each scientist patiently formulates, tests and discards hypotheses, and thereby each succeeding one stands on the shoulders of the one who came before.  What might be called this 'Whig theory of the history of science' has now been largely discarded for the far more realistic Kuhnian theory of paradigms.  For our purposes the important point of the Kuhn theory is that a very few people patiently test anything, particularly the fundamental assumptions, or basic 'paradigm,' or their theory: and shifts in paradigms can take place even when the new theory is worse than the old.  In short, knowledge can be and is lost as well as gained, and science often proceeds in a zig-zag rather than linear manner.  We might add that this is particularly true in the social or humane sciences.  As a result, paradigms and basic truths get lost, and economists (as well as people in other disciplines) can get worse, and not better, over time.  The years may well bring retrogression as well as progress.

~ Murrary Rothbard, Economic Thought Before Adam Smith: An Austrian Perspective on the History of Economic Thought, Volume I, "The celebrated Adam Smith," p. 438