本文既有的研究基礎上，進一步探究多瑪斯德行倫理學之「德行」基礎之「習慣」概念，此一研究主題主要見於多瑪斯大著《神學大全》第二部的第一部份，問題四十九到問題八十九。多瑪斯從「普遍的」(問題49到問題54)和「特殊的」(問題55到問題89)兩方面進行探討；其中普遍的面向又分為：習慣的本性(問題49)、習慣的主體(問題50)、習慣的原因(問題51到問題33)和習慣的區分(問題54)；特殊的面向又以「好的習慣即德行」(問題55到問題70)，以及「壞的習慣即惡行」(問題71到問題89)為探討要點。有主要從普遍的面向探討多瑪斯的「習慣之本性」，並進而中國哲學的習慣之「習」作一初步對比。初步結論為：多瑪斯的「習慣」概念之內涵遠比亞里斯多德所述及者，更為豐富周延；不指實體的活動傾周或狀態，也指人的理智與意志行為的結果及其現實。中國哲學由於文化的差異，哲學家對「習慣」問題的呈現與處理則大相逕庭。

Based on the existing research, this paper is intended to explore further the concept of “habits,” which is the foundation of “virtue” in Thomas Aquinas’s virtue ethics. Such a theme is largely found ion Part I, Summa Theological II, form Question 49 to Question 89. Aquinas approaches this concept both in “general” (Question 49 to Question 54) and in “particular” (Question 55 to Question 89). And the general aspects are divided into the nature of habits (Question 49), the subject of habits (Question 50), the cause of habits (Question 51 to Question 53) and the distinction of habits (Question 54), while the particular aspects are mainly explored on terms of “good habits as virtue” (Question 55 to Question 70) and “bad habits as sin” (Question 71 to Question 89). This article is intended to explore Aquinas’s “nature of habits” in general and contrast it with the idea of “habits” in Chinese philosophy. And the preliminary conclusion is: the content Aquinas’s concept of “habits” is much more well-rounded than Aristotle’s referring not only to the inclination and state of the substance but also to the result and act of human beings’ acts of reason and will. Due to the cultural differences between Chinese and western philosophies, the presentations and treatments of the issue of “habits” by philosophers from both sides are extremely distinct from one another.