Prudence in Thomas Aquinas

When referring to prudence, Aquinas did not refer to the same meaning as today we give the word, as a simple synonymous of wariness and precaution. However, there is some remnant of the idea of prudentia in modern prudence. The prudent for Thomas is the one who “envisions the possibilities that can occur in the contingent situations,” but it don´t stays only on that.

Prudence belongs to the field of knowledge, but it is different from other intellectual virtues – wisdom, science and understanding – that deals with the necessary. Prudence, like art, is about what is contingent. In the case of art, what is being dealt with is the external matter. Prudence, instead deals with what can act, that is, the agent itself. It is a virtue of practical reason and not speculative reason. Its role is to apply the universal principles determined by speculative reason in acting (particularly). It does not indicate the end of moral virtues, but rather how to deal with the means to achieve this end.

There are three acts that prudence involves: the act of advising, the act of judging and the act of commanding. The first is a synonymous of inquiring (an act of advising oneself); the second, judging, is the act of evaluating what has been discovered, an act pertaining to speculative reason. The third act, that of commanding, is where what has been advised and judged is applied to action. Of the three acts, this is the closest to practical reason, therefore, the main act of prudence.

If the desired end is a bad end, the result of bad advice and judgment, that type of prudence is considered a false prudence, even if the means found by her are best suited to achieve that purpose. If the end is good and the means to this end are adequate, but the end in question is only a fragmentary sector of human life, not the end common to the totality of human life, prudence is true, but imperfect. Consequently, it is true and perfect the prudence that in relation to the good of life in its wholeness, judges and commands correctly.

There are also three types of prudence parts: the integral parts, the subjective parts and the potential parts . The integral parts are those necessary for the fullness of the act of virtue and are divided into the parts belonging to the cognitive dimension of prudence and its dimension of command , where knowledge is applied to action. The first group includes memory, reason, intelligence, docility and sagacity . The second group includes social security, circumspection and prevention .

The memory is knowledge itself, which refers to the past, the intelligence to present moment. To obtain such knowledge, an openness to learn is necessary , something typical of docility. Another way to obtain such knowledge is through discovery, which is done by well conjecturing, or eustochia, a virtue of which sagacity is part, with sagacity being the conjecturing about the means in a quick and easy manner. From know things the agent passes to judge or know other things, a characteristic of reason. The reason of prudence originates in two types of intelligence, one related to the knowledge of universal principles – both theoretical, and practical, as the principle of to do no harm to anyone – and other intelligence that deals with the singular and contingent, which in the syllogism of prudence it is what provides the smallest premise for action.

For reason to be able to command action in the right way, it is necessary that the reason order something appropriate at the objective, an appropriate function for foresight, the main part of prudence, since all other requirements for the existence of prudence are essential exactly for something go straight to an endthe circumstances of the situation should also be considered, something appropriate to circumspection; and obstacles must be avoided, a function assumed by prevention, which must seek goods and avoid evils .

The subjective parts of prudence are its various species, which is seen in the proper sense, are prudence by which a person directs his self and prudence by which one drives others – that can be various types of prudence, such as military prudence, the prudential to rule, the domestic prudence, the political prudence. In a broad sense, including speculative science, there are three ways of prudence reasoning: from necessary premises, obtained through demonstration; from presumed premises; and judging from conjectures, which induce to a certain suspicion.

The parts attached to a virtue are called potential partsIn the case of prudence, eubulia is attached to it which deals with judgment in relation to things that happen in an ordinary way and gnome, relating to judgment about situations in which sometimes it is necessary to distance oneself from common laws, and to judge according to principles superior to them, since it is bad to comply with an unjust law.

In opposition to the parts of prudence are the precipitation that occurs in relation to the act of advising and contains the lack of docility, memory or reason; the inconsideration that takes place in relation to the act of judgment, which contains the lack of prevention and circumspection; and neglect – the abdication of the act of choosing, where reason is not requested to command what (and how) should command – and the inconstancy containing the unpredictability, and a poor intelligence and sagacity, where there is a failure of reason in commanding what was deliberated and judged.


AQUINO, T. D. (2005). A prudência: a virtude da decisão certa. Tradução de Jean Lauand. Martins Fontes, São Paulo.

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