Question Two: On the Mode by Which the Sacraments Cause Grace

41. Notions. - A cause is a principle influencing the being of another. An extrinsic cause is twofold: for either it influences by acting or operating, and then it is efficient; or it influences by way of object, insofar as it is known, and then it is a good moving an agent that for its sake he do something, and this is final.

An efficient cause is divided:

a) on the part of the power by which it acts, into principal, which by its own proper and complete power operates an effect similar or proportioned to itself; and instrumental, which, by exercising its proper action and producing an effect proportioned to itself, is at the same time moved by a principal agent, and thus cooperates toward its effect: the operation of an axe is to cut, but insofar as it is moved by the craftsman, it cuts artfully;

b) on the part of the mode by which it attains the effect, into perfecting, which effects the ultimate perfection of the thing, as an animal generates an animal; and disposing, which effects some disposition requiring from another the introduction of the ultimate perfection: thus the action and seed of the father do not effect the human soul, but a disposition in the matter which requires the infusion of the soul.

A moral or occasional cause is that which, by bringing forward a motive, for example by its dignity, excites, attracts, and thus moves an intelligent cause to produce an effect; it is called moral because, according to the common estimation, the effect of the intelligent cause is rightly imputed to it. By some it is called an efficient cause, because it moves the person to effecting; but it can be called efficient only metaphorically and improperly, for the motive moves, not indeed by producing something, but by way of object, insofar as it is known and someone acts for its sake; and therefore it is reduced rather to the causality of end than to the causality of efficiency.

Now it is asked whether the sacraments are merely occasional or also moral causes, or rather truly efficient instrumental causes, or even physical causes, and how their causality can be understood. In this question it will be difficult to arrive at true certitude; wherefore it is permitted to us in this matter to speak by reporting or opining, rather than by disputing or deciding.