Aquinas Day By Day


Aquinas’s Topic: The range of the practical sciences

Scripture: Heb 3: 12: “Take care, brethren, that none of you may have an evil and unfaithful heart, leading you to fall away from the living God. Encourage yourselves daily while it is still ‘today,’ so that none of you may grow hardened by the deceit of sin. For we share in Christ if only we hold our first confidence firm to the end.”

Church Calendar: St. Hilary of Poitiers

Aquinas’s text: Prologue to his Sententia libri ethicorum, written Paris, 1271-2

Br. Thomas explains his rationale for distinguishing the three practical disciplines of ethics, economics, and politics. For him, all three are moral disciplines:

One must realize that the whole that is the many who live in a city or is a family living in a household have only the unity of an order, which is not something absolutely one. Therefore, a part of this whole can have an operation that is not an operation of the whole. For example, a soldier in an army can have an operation that is not the operation of the whole army. Nonetheless, the whole has some operation that is not proper to one of its parts but is proper to the whole. For example, an engagement of the whole army or the movement of a ship is the operation of the many who are rowing the ship. Now there is another kind of whole that not only has a unity of order but also a unity of composition or connection or continuity, and in accord with this kind of unity it is absolutely one and consequently there is no operation of a part that is not also an operation of the whole. For in continua the motion of whole and part are the same, and likewise in things composed or connected the operation of a part is the cause of the operation of the whole. Therefore, it is necessary that consideration of such wholes and parts pertain to the same science. But it does not pertain to the same science to consider the whole that only has a unity of order and its parts.

This is why moral philosophy is divided into three parts. The first of these considers the operations of one human that are for the sake of an end, and this is called individual morality. The second considers operation of the many who live in one house, and this is called economics [or family morality]. And the third considers operations of the many who live in a city, and this is called political morality.

Sciendum est autem, quod hoc totum, quod est civilis multitudo, vel domestica familia habet solam ordinis unitatem, secundum quam non est aliquid simpliciter unum; et ideo pars huius totius potest habere operationem, quae non est operatio totius, sicut miles in exercitu habet operationem quae non est totius exercitus. Habet nihilominus et ipsum totum aliquam operationem, quae non est propria alicuius partium, sed totius, puta conflictus totius exercitus. Et tractus navis est operatio multitudinis trahentium navem. Est autem aliud totum quod habet unitatem non solum ordine, sed compositione, aut colligatione, vel etiam continuitate, secundum quam unitatem est aliquid unum simpliciter; et ideo nulla est operatio partis, quae non sit totius. In continuis enim idem est motus totius et partis; et similiter in compositis, vel colligatis, operatio partis principaliter est totius; et ideo oportet, quod ad eamdem scientiam pertineat consideratio talis totius et partis eius. Non autem ad eamdem scientiam pertinet considerare totum quod habet solam ordinis unitatem, et partes ipsius.

Et inde est, quod moralis philosophia in tres partes dividitur. Quarum prima considerat operationes unius hominis ordinatas ad finem, quae vocatur monastica. Secunda autem considerat operationes multitudinis domesticae, quae vocatur oeconomica. Tertia autem considerat operationes multitudinis civilis, quae vocatur politica.

[Introductions and translations © R.E. Houser]