This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Ancient sources report the Stoic cardinal virtues as a set of four, each governing a distinct domain of a person's life while remaining, in the Stoic view, ultimately one and the same excellence seen from different angles. Phronesis, practical wisdom, comes first because the school treated it as the root the other three grow from: courage is phronesis applied to danger, justice is phronesis applied to one's dealings with others, and temperance is phronesis applied to one's own appetites. A person could not, on Stoic terms, hold one cardinal virtue without the rest, since a genuinely wise judgment already accounts for how to act bravely, fairly and moderately in the same breath.
Diogenes Laertius, writing centuries after the school's founding, preserves a division of phronesis into further species: good sense in weighing a decision, good calculation in reasoning toward the right outcome, quickness of mind in seeing what a situation calls for, and discretion in judging what to say and when. Stobaeus's later anthology of Stoic ethical doctrine gives a similar breakdown, and both sources agree that phronesis is inseparably the knowledge of what is genuinely good, genuinely bad, and merely indifferent, health, wealth, reputation, pleasure and their opposites, none of which counted as good or evil in Stoic ethics at all.
The Stoics distinguished their phronesis from Aristotle's practical wisdom on exactly this point. Aristotle's phronetic person aims at a good life that still includes external goods in a supporting role; the Stoic sage's phronesis answers to virtue alone as the sole good, so the wise person's practical judgment never has to weigh virtue against anything external, because nothing external is weighed at all. This is also why Stoic sources insist that only the fully wise person, a figure the school treated as vanishingly rare, possesses phronesis in the strict sense; everyone else is progressing toward it or has not begun.