[N]o principality is secure without having its own armies; on the contrary, it is completely dependent on Fortune, because it does not have the valor [virtù] which loyally defends it in the midst of adversity.
Machiavelli frequently asserts the importance of not relying on good fortune and of preparing for the worst. In this case, he strongly believes that a principality without its own army risks all. So much of Europe and especially Italy at this time maintained a state of high alert against invading mercenaries or auxiliary forces loyal to an outside power. By saying the principality completely depends on Fortune without its own army, Machiavelli explains that both mercenary and auxiliary forces, though widely deployed, are completely useless.
[P]rinces become great when they overcome the difficulties and obstacles that confront them, and therefore Fortune, especially when she wants to make a new prince great . . . causes enemies to appear for him and has them undertake campaigns against him[.]
Machiavelli asserts that Fortune has agency over human affairs. While not a god as the Romans believed, he names Fortune as an active force in the world. He believes that Fortune shows preference for certain princes by, ironically, making their jobs harder. A truly great prince will fight and succeed against everything Fortune throws against him, thus winning the acclaim of the people and securing his rule. Machiavelli personifies the role of challenges in the histories of great men, and he may be attributing this intent to Fortune so princes such as Lorenzo de Medici are not discouraged from undertaking the hardships that go along with leadership.
[S]o that our free will may not be extinguished, I think it may be true that Fortune is the arbiter of half of our actions, but that she still leaves the other half of them, more or less, to be governed by us.
Machiavelli worries that people who believe that Fortune controls their destinies will not try to aid themselves. He postulates instead that humans have control over half of their actions, and if prudent, people will make plans to minimize the damage a bad turn of Fortune could cause. Machiavelli likens anticipating Fortune to controlling a river with dikes so the river will be less destructive during a flood. The assertion that free will can balance Fortune, while possibly controversial in Machiavelli’s day, reflects a new humanist philosophy beginning to take root in Europe at the writing.
[I]t is better to be impetuous than cautious, for Fortune is a woman, and it is necessary, if you wish to keep her down, to beat her and knock her about. And one sees that she lets herself be conquered by men of this sort more than by those who proceed coldly.
Although Machiavelli refers to Fortune as a woman, he did not create the idea. His Fortune represents the weaker descendant of the Roman goddess Fortuna, or Fate. Unlike Fortuna, Fortune affects but does not guarantee the final outcome of events. Laying aside the misogyny inherent in the image Machiavelli presents, his metaphor of impetuousness knocking Fortune about makes sense: By making sudden, unexpected movements and changes of plan, a prince can potentially evade bad future outcomes—not so much by surprising Fortune per se, but really, by surprising his enemies.