Economics

Economics, it has been widely stated, is the only science that has been awarded the Nobel Prize one year apart for completely different theories, findings, and interpretations.  The problem with economics, and economic policies is that they are based on theories and have been applied in differing situations. As a theory, therefore, they are not proven as facts to return an exact and permanent answer. As they have been applied at and for varying times, to varying degrees (ie, some policies adopted, others altered, others eliminated, etc), and for varying reasons, there is little practical proof that one theory is entirely better than the others.  What do you make of this line of thought?