 So far we have had an account of what scientists typically do do and what Lakatos thinks that they ought to do. But what about the Demarcation Criterion between science and non-science or between good science and bad? Even if it is sometimes rational to persist with the hard core of a theory when the hard core plus some set of auxiliary hypotheses has been refuted, there must surely be some circumstances in which is it rational to give it up! The Methodology of Scientific Research Programme has got to be something more than a defence of scientific pig-headedness! As Lakatos himself puts the point: