Selection from A Course in Thomistic Ethics | D. Q. McInerny

(Elmhurst, PA: The Priestly Fraternity of Saint Peter, 1997), 142-143.

It is easy to see how habits would have to figure prominently in any serious examination of the moral life. Common sense tells us that someone whom we would be inclined to call either a good person or a bad person is not one or the other simply on the basis of either occasional good acts or occasional bad acts, but rather on the basis of a set pattern of either good or bad activity. One's dominant moral identity derives not from 'now and then' behavior but from behavior which displays consistent configurations over the long term. It is, in other words, habitual behavior. Habitual behavior is especially significant because it is revealing of character. It declares who we are in terms of what we do.

In precise philosophical terms we can define a habit as a permanent form, as a quality which governs a certain human power or capacity for action, or we could say simply that a habit is a principle that draws forth a certain kind of act. Further, we could say that it is a quality that relates to the type of human action which in itself is not always easy to perform, but which, on account of this quality (i.e., the habit), one can not only do but in doing even find a certain amount of pleasure. St. Thomas's term for what we are discussing here is habitus, and he helpfully calls our attention to the fact that this term derives from the verb habere, 'to have.' This bit of etymological information reveals something important about the nature of habit. A habit, in the most basic sense, is something we 'have,' that is to say, it is a permanent possession. It is not a sometime thing, here today and gone tomorrow, but rather represents what a person is as a moral being. By saying that a habit represents what a person is we mean to stress its permanent nature. The permanency of habit, however, is relative, not absolute. Habits can become more or less intense; they can be brought into being, and they can be eradicated. The relative permanency of habit is either good news or bad news, depending upon the moral quality of the habit in question. Of course, the whole purpose of the moral life is to create and build up good habits, and quash bad ones. A habit is not part of man's essence, as such. Man's essence is one, but it contains many powers, and habit has directly to do with those powers.

So, habit is a possession, something we have, and we have it with respect to something else, specifically with respect to action. A habit helps us do difficult things with facility. St. Thomas leans heavily upon Aristotle for the development of his own ethical theory concerning habit, and in his discussion of the subject he quotes liberally from Aristotle's works. From the Metaphysics we hear Aristotle tell us that 'by a habit we mean a disposition by which the one possessing it is either well or ill disposed, with respect to himself or something other than himself.' (S.T., I-II, q. 49, a. 1) And he offers health as an example of what he is talking about here. In the Physics, with good habits especially in mind, Aristotle describes habits as 'certain dispositions of the perfect which are ordered to what is best.' (S.T., I-II, q. 49, a. 2) And in the Ethics, putting stress on the peculiarly moral dimension of habits, he talks about them in terms of those possessions which enable us to deal effectively with the passions.