Abstract
I discuss Aquinas’s view of habit—the genus to which virtue belongs. The first article in both of Aquinas’s sustained treatments of the virtues in general (STh I.II.55-67 and QDV 1) asks whether virtues are habits. Thus, Aquinas’s pedagogical strategy is to elucidate the virtues in terms of their nature as habits. Following this strategy, I explore Aquinas’s discussion of habits in Questions 49-54 of the prima secundae by tracing three important topics: the essence of habits, the cause of habits, and the increase of habits. By the end of this paper, the reader will have a strong grasp of the nature and types of habits and the different ways in which they can increase.