upward grade will always reach a point beyond which they cannot rise
further, but they will not remain permanently on this level, they
will begin to decline; for human things are always in motion and
therefore must go up or down. Similarly, declining states will
ultimately touch bottom and then begin to ascend. Thus a good
constitution or social organisation can last only for a short time.
[Footnote: Machiavelli's principle of advance and decline: Discorsi,
ii. Introduction; Istorie fiorentine, v. ad init. For the cycle of
constitutions through which all states tend to move see Discorsi,
ii. 2 (here we see the influence of Polybius).]

It is obvious that in this view of history Machiavelli was inspired
and instructed by the ancients. And it followed from his premisses
that the study of the past is of the highest value because it
enables men to see what is to come; since to all social events at
any period there are correspondences in ancient times. "For these
events are due to men, who have and always had the same passions,
and therefore of necessity the effects must be the same." [Footnote:
Discorsi, iii. 43.]

Again, Machiavelli follows his ancient masters in assuming as
evident that a good organisation of society can be effected only by
the deliberate design of a wise legislator. [Footnote: Ib. iii. 1.
The lawgiver must assume for his purposes that all men are bad: ib.
i. 3. Villari has useful remarks on these principles in his
Machiavelli, Book ii. cap. iii.] Forms of government and religions
are the personal creations of a single brain; and the only chance
for a satisfactory constitution or for a religion to maintain itself
for any length of time is constantly to repress any tendencies to
depart from the original conceptions of its creator.