Economics it has been widely stated is the only science that has been awarded th

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?