Stoic philosophy is driven by four guiding virtues – wisdom, courage, justice, and temperance.
They are the principles that students should seek to practice if they are to exemplify the character of a Stoic.
The virtues are thought to be derived from the teachings of the Greek philosopher Plato, who defined the same four principles in his Republic (Book IV, 426–435).
Below is a handy infographic displaying the definition of each virtue. Feel free to print it and keep it nearby as a reminder to yourself.
(The slightly fuller descriptions are in the text at the bottom.)
Wisdom
(Greek: φρόνησις “phronesis” Latin: prudentia)
The ability which by itself is productive of human happiness; the knowledge of what is good and bad; the knowledge that produces happiness; the disposition by which we judge what is to be done and what is not to be done.
Courage
(Greek: ανδρεία “andreia”, Latin: fortitudo)
The state of the soul which is unmoved by fear; self-restraint in the soul about what is fearful and terrible; boldness in obedience to wisdom; being intrepid in the face of death; the state which stands on guard over correct thinking in dangerous situations; force of fortitude in respect of virtue.
Justice
(Greek: δικαιοσύνη “dikaiosyne”, Latin: iustitia)
The unanimity of the soul with itself, and the good discipline of the parts of the soul with respect to each other; the state that distributes to each person according to what is deserved; the state on account of which its possessor chooses what appears to him to be just; the state underlying a law-abiding way of life; social equality; the state of obedience to the laws.
Temperance
(Greek: σωφροσύνη “sophrosyne”, Latin: temperantia)
Moderation of the soul concerning the desires and pleasures that normally occur in it; harmony and good discipline in the soul in respect of normal pleasures and pains; concord of the soul in respect of ruling and being ruled; normal personal independence; good discipline in the soul; rational agreement within the soul about what is admirable and contemptible; the state by which its possessor chooses and is cautious about what he should.
