Prudence in Stoicism
The striking text already noted in chapter 3 reminds us how Zeno, Stoicism's founder, retained the foundational role of prudence found in Socrates, Plato, and Aristotle. Plutarch, writing around the end of the first century, reports Zeno's position as follows: [Zeno of Citium … defines prudence in matters of distribution as justice, (prudence) in matters of desire as temperance, and (prudence) in matters of standing firm as courage] (Moralia, 441 A). This text depicts Zeno setting forth the four traditional cardinal virtues—prudence, justice, temperance, and courage—and then making prudence the primary virtue by viewing the other three virtues as versions of it. The Stoic needs prudence, and not justice, temperance, or courage, to know, in any particular situation, what is the virtuous thing to do.
It might seem that Stoic ethics has little need for the kind of deliberative prudential reasoning that we saw in Socrates, Plato, and Aristotle. As we saw in chapter 3, the Stoics believe that all natural reality (phusis) forms a single complete whole permeated by a universal reason (logos) that organizes and directs it. Fortunately, this immanent logos, which some Stoics called a world-soul or a god, is providential—it directs everything for the best. In Stoicism, what looks like a bad thing or a tragedy is merely a part of a predetermined rational plan achieving the best possible outcome.