Contemporary authors have expressed their appreciation for Thomas Aquinas’s holistic approach to our ethical lives. In an age when virtues are often emphasized without an explicit and well-worked-out moral psychology, scholars find solace in panoptic treatments like that of Aquinas. This medieval mendicant has girded his conception of virtue with a profound anthropological depth. That account begins with why humans need the virtues. The human person is capable, by his own free will, to become so many different things. He is free to shape, hone, and altogether determine his various human powers in a multitude of ways. Just as a doctor can use his knowledge to either save life or take it, so too each person can mold his or her own natural powers for either good or evil deeds. Over time, these natural powers can become inclined toward such deeds and aims. By this inclination, the power becomes a determining force among the other powers of the human person.