Commentaria in Summam contra Gentiles, Liber III

Having shown that God preserves all things in being, St. Thomas wishes to show that inferior agents do not give being except insofar as they act in the divine power ¹.

I. And he argues first thus. Nothing gives being except insofar as it is a being in act. But a thing is preserved in being in act through divine providence. Therefore, that something gives being, it has from the divine power.

Secondly. Being is the common effect of all agents. Therefore, all things produce this effect insofar as they are ordered under the first agent, who is God, and act in his power. — The antecedent is proved. Because every agent makes to be in act: understand, directly or indirectly, primarily or secondarily ². — The consequence, however, is proved. Because, since many things do not make one except insofar as they are one, when diverse agents are ordered under one agent, it is necessary that the effect which is commonly produced by them belongs to them according as they are united in participating in the motion or power of that agent. This is made clear from what is seen in an army.

Thirdly. In every action, being in act is principally intended, and ultimate in generation: since, once it is possessed, the action of the agent and the motion of the patient cease. Therefore, being is the proper effect of the first agent, namely God, and all other things produce it in his power. — The consequence is proved. Because in all ordered agents, what is ultimate in generation and first in intention is the proper effect of the first agent. This is made clear in the building of a house.

II. Fourthly. What is most perfect in all agents ³ is being. Therefore, etc. — The antecedent is proved. Because any nature or form is perfected through this, that it is being in act, and is compared to it as potency to act. — The consequence, however, is proved. Because the ultimate in goodness and perfection among those things to which a second agent has power is that to which it has power from the power of the first agent: since the completion of its power is from the power of the first agent.

Concerning the assumption for the proof of the antecedent, it must be considered that, as was shown in the First Book ⁴, being is the ultimate actuality, which can be actualized by no other act, but, if it is limited, this is not through some act, but only through a receptive and potential principle. Therefore, however much a form is a certain act, compared nevertheless to being itself, it has the character of the potential: for, although it is the formal cause of being, yet because it is not constituted in the nature of things except through being itself as through the ultimate actuality, it is necessary that it have a comparison to it as potency to act.

III. Fifthly. The first in all effects is being: since all other things are determinations of it, — understand, after the manner of the potential and the receptive, but not after the manner of act. Therefore, it is the proper effect of the first agent: and second agents, which are as it were particularizing and determining the action of the first agent, produce as proper effects the other perfections, which determine being. Therefore, etc. — The first consequence is proved. Because according to the order of causes is the order of effects.

2. Concerning that proposition, Second agents determine the action of the first agent, it must be noted that this is not to be understood as if secondary agents operate something toward the divine action as it is in itself, since his action is his substance: but it is understood, as is evident from what was said above ⁵, according as it is terminated to some effect through the mediation of second causes. For thus the divine power and action, according as it is received in a second cause, receives limitation and determination from the condition of the second cause, as from the condition of a receptive principle: because whatever is received in another is received after the manner of the receiver.

3. But a doubt occurs. For there seems to be a contradiction in the words of St. Thomas. For in the third argument he assumes that being in act is principally intended and ultimate in generation: but in this argument he assumes that the first in all effects is being. And he seems to understand this of the first in generation: because he adds that all other things are determinations of it; and also because, if he understood it of the primacy of perfection, this argument would not differ from the preceding one, in which he assumes that being is most perfect.

He answers, as was said above in the Second Book, chap. XXI ⁶, that being taken absolutely, as it is compared to this or to that being, is first in generation, just as the indeterminate is to the determinate: but as it is compared to the term of any production whatever as act to potency, thus it is ultimate, as the completion of all perfection.

IV. Sixthly. God alone is being through essence: since he alone is his own being. Therefore, the being of every existing thing is the proper effect of God. Therefore, etc. — The first consequence is proved. Because what is such through essence is the proper cause of what is such through participation.

Note that many of the above-mentioned arguments proceed from the same foundation, namely from this, that being is the proper effect of God: but nevertheless, because that foundation is shown through many and diverse means, St. Thomas establishes several arguments.

The conclusion is confirmed by the authority of Wisdom 1; and by the authority of the Book of Causes, prop. 22.