“We can show that we need virtuous dispositions for three reasons. First, for steadfastness in our operations.... Second, we need them to perform a perfect operation readily.... Third, we need virtuous dispositions to bring our perfect activity to fulfillment pleasurably.”
–St. Thomas Aquinas (Disputed Questions on Virtue)
The Virtues in General
Our word "virtue" comes from the Latin vir, which means power; a virtue is the perfection of a power. Human virtues are firmly established and readily responsive dispositions in the powers of human beings, especially in reason and in the appetites. Aquinas divides the virtues into the theological, containing faith, hope, and charity, and the cardinal, including prudence, justice, fortitude, and temperance; all the other virtues fall under these seven. While the theological virtues are received by grace (and thus are often called "infused" virtues), the cardinal virtues are acquired by effort (also known as "acquired" virtues). A truly liberal education considers what efforts individuals and communities ought to make in order to seek, to preserve, and to promote the virtues.
The Virtues in Particular
“Thus, the theological virtues, whose object is God, are superior to the others. Among these charity is greatest, because it joins us most closely to God. Next, hope is greater than faith, because hope in a way moves our affections to God, while faith causes God to exist in us as an object of thought. Among the other virtues, prudence is the best, because it governs the others. And after it comes justice, by which one is well ordered not only in oneself, but also toward others. After that comes courage, by which one scorns mortal dangers for the sake of the good. And after that comes temperance, by which one scorns the greatest bodily pleasures for the sake of the good.” –Thomas Aquinas (On the Cardinal Virtues, 3. reply)
The Purpose of the Virtues
The purpose of the virtues is to dispose us to act in accord with reason and to receive grace fruitfully. Without virtue, good action is difficult; with virtue, however, good action is not only easier to attain, but also more inherently desirable and enjoyable. In fact, one distinguishing mark of the possession of a virtue is taking pleasure in a good action. Free from evil and free for good thoughts and actions, our faculties incline us toward what is truly noble and beneficial when they are perfected by virtue. The greatest action that man's highest faculties can perform, with the aid of grace, is the contemplation of God. Thus, all the virtues ultimately dispose us for the activity of contemplating God.