 This flexibility yields the core of the “practical” advice that Machiavelli offers to the ruler seeking to maintain his state: exclude no course of action out of hand, but be ready always to perform whatever acts are required by political circumstance. Yet Machiavelli himself apparently harbored severe doubts about whether human beings were psychologically capable of generating such flexible dispositions within themselves. In spite of the great number of his historical examples, Machiavelli can point in The Prince to no single ruler who evinced the sort of variable virtù that he deems necessary for the complete control of fortune. Rather, his case studies of successful rulers repeatedly point to the situation of a prince whose characteristics suited his times but whose consistency of conduct (as in the case of Pope Julius II) “would have brought about his downfall” if circumstances had changed (Prince CW 92). Even the Emperor Severus, whose techniques Machiavelli lauds, succeeded because he employed “the courses of action that are necessary for establishing himself in power”; he is not, however, to be imitated universally (Prince CW 73). Machiavelli's evaluation of the chances for creating a new, psychologically flexible type of character is extremely guarded, and tends to be worded in conditional form and in the subjective mood: “If it were possible to change one's nature to suit the times and circumstances, one would always be successful” (Prince CW 91, translation revised). Such observations must make us wonder whether Machiavelli's advice that princes acquire dispositions which vary according to circumstance was so “practical” (even in his own mind) as he had asserted.