ABSTRACT
Point(1)isanecessarydemand,andaconservativedemand.Itprevents regression.Point(2)isoptionalanddesirable.Itisrevolutionary.Notall progressinsciencehasarevolutionarycharacter,althougheveryimportant breakthroughinscienceisrevolutionary.Thetwodemandstogether ensuretherationalityofscientificprogress;thatis,anincreaseinverisimilitude.
