Question Three: Concerning the Potential Parts

S. Th. II-II, q. 80.

257. Potential parts are annexed virtues which agree in something with the cardinal virtue, but in another respect fall short of its perfect account; whence they do not have the whole power of the cardinal virtue. This, namely, is concerned with the principal and more difficult matter; the annexed virtues are concerned with secondary, less difficult matter, in which they imitate the principal virtue. Justice, therefore, is concerned with that which is principal in operations, namely, a strict due which is rendered even to equality in every way; — the joined virtues are concerned with a due which either is not strict, or is not rendered to equality.

258. The principal potential parts of particular justice are eight, as St. Thomas shows: Justice consists in this, that what is due is rendered to another according to equality. But several virtues agree with justice in this, that they are toward another, which nevertheless fall short of justice:

A. three fall short in rendering the due, because they do not render an equal thing, that is, they do not render as much as has been received, namely:

1. religion (to which, sin being supposed, penance is added) toward God;

2. piety toward parents;

3. observance toward those constituted in dignity;

B. others fall short because they do not render a strict due which is owed by law, but a moral due which is owed from the honesty of virtue, whether a) that due is necessary for the honesty of morals, either by reason of the one owing:

4. truth, by which someone shows himself to another as he is; or by reason of him to whom it is owed:

5. gratitude, by which someone compensates another in goods; and

6. vindication, in evils; — or b) it is a due insofar as it only contributes to greater honesty of morals, such as

7. liberality, to which mercy is akin,

8. affability, and certain others which could be called by the general name equity.¹

¹ Here, ad 3. This equity is not taken in the same sense as epikeia, which is special equity pertaining to legal justice. Concerning this it was said in the introduction on Laws, n. 286-287, and it will be said below, n. 891.

Therefore those virtues are rightly said to be annexed to justice.