Definition

(Summa Theologica, II-II, qq. 47-56.)

Definition.—All the definitions of prudence are in substantial agreement, and from them we may formulate a detailed definition as follows: “Prudence is the virtue that consults well about the means to be used for leading a good life and applies the knowledge acquired through consultation to particular contingencies as they arise.”

(a) Thus, prudence consults well, for its office is to study ways and means to right conduct, and to arrive at a sound judgment in spite of various uncertainties or unknown factors. Of the two practical virtues of the intellect, namely, art and prudence, the former deals with the application of right reason to cases in which there are, for the most part, certain and determinate ways of arriving at the end in view (e.g., the rules of logic or grammar, the methods of music or sculpture); while the latter has to do with the application of right reason to cases in which the ways of obtaining the end in view are not certain or determinate (i.e., the infinitely varied questions of lawfulness or unlawfulness that present themselves in concrete and particular situations).

(b) Prudence studies the means to a good life; and hence we do not consider a man as generally prudent, if he consults well for this or that particular good end, but not for the general end of leading a good life. Nevertheless, prudence falls short of the Gift of Wisdom, for prudence is concerned with human good, wisdom with divine good.

(c) Prudence applies knowledge to the direction of conduct, for the purpose of the practical virtues of the intellect is to guide the activities and productions of man according to the light of right reason. It should be noted, however, that whereas the application of knowledge is intrinsic to prudence, it is extrinsic to art; for prudence includes in its very essence a determination of the will to goodness, but not so art. Hence, a painter is not the less skilled in his profession if he voluntarily fails to exercise it or exercises it badly, but a person skilled in moral science is imprudent if voluntarily he fails to use his knowledge or uses it amiss. The sin against art is not to know; the sin against prudence is either not to know what one should know or not to apply rightly what one does know.