8. From the standpoint of supreme influence, the argument proceeds as follows. The perfection of influence necessarily requires that influence not be without divine essence, presence, and power; therefore, by equal reason, it cannot be multiplied without the multiplication of essence, power, and presence; therefore, since there are many divine influences, there are also many essences.
9. From the standpoint of causality, the argument proceeds as follows. The first cause is most perfect, is first and immediate, and therefore also proper. But when the effect is multiplied, it is necessary that the proximate and proper cause be multiplied; therefore it is necessary that multiplication be posited in the first cause, since multitude is posited and exists in the effects caused by it.
10. Likewise, from all these considerations an objection is raised against all the foregoing: because the most perfect sublimity in nature and power, wisdom and goodness, influence and causality is the reason for positing multitude in caused effects; therefore, if the same thing is not the cause of opposites, it seems that these considerations lead rather to positing multitude than unity on the part of the efficient cause, and thus tend rather toward the opposite than toward the proposition.
CONCLUSION.
That God is one is a truth not only believable but also intelligible.
I respond: It must be said that this truth, that God is one, is a truth not only believable, but also intelligible: since it is necessary and certain not only from the testimony of Scripture and the illumination of grace, which is found in faith; but it is also certain from itself and from the testimony of creatures.
From itself, therefore: because the divine being, on account of its singular sublimity and sublime singularity, possesses unity in every way. For since God has every perfection in himself, and this in the highest degree and most excellently, he is shown to be one not only from the sublimity of nature and wisdom, power and goodness and influence and causality, but indeed from all his conditions and noble properties that are attributed to him in the highest degree. Hence all conditions attest to the unity of the supreme essence.
From the testimony of creatures also: because every creature, just as it has natural goodness, so also is shown to have unity. " For nothing can exist unless it is one," as Boethius and Augustine say,
and as sense and intellect teach. Therefore, just as every creature by its goodness proclaims that in God there is true and supreme goodness, so by its unity it proclaims that the cause of all things is one in itself.
Nor does the diversity of things stand against this testimony. For every diversity of things is comprehended within one universe, which in itself is indeed finite and limited and perfect. But this would not be so unless that plurality were reduced to something in which there would be a stopping point: and therefore it is necessary that all things be reduced to one ultimate end and one first principle, otherwise there would be a regress to infinity. Therefore the very universe of things testifies that God is one: whence, just as it is impossible for one circumference to have, nor can one rationally conceive, any but one center, from which lines flow and to which they are reduced as to a terminus: so in one universe one cannot posit or understand anything but one God alone.
This is therefore necessary and known, and so well known that no one having the use of reason doubts it, if he knows "what is signified by the name." For if by this name God is signified the first and highest principle of all things; since in this the whole universe is enclosed, whoever understands this consequently affirms that God is one. Whence, just as principles are self-evident, because they are immediately known through knowledge of their terms; so to everyone understanding the signification of the terms it is indubitably certain that God is one.
Many, however, have erred concerning the number of gods: for ignorance of the signification begot deception concerning the supposit, and this introduced the heresy of the plurality of gods. For because men supposed that to be God which surpasses human power, or human knowledge, and they saw that demons could do this; therefore they believed them to be gods: and they erred and were blinded and bent toward the worship of idols: which indeed is most absurd, and no wonder, because "a small error in the beginning is great in the end." From this error philosophy rescues, but much better the Christian faith: which commonly concur in this, that the divine being is supremely one.
Whence the arguments that show this are to be conceded, because they conclude what is true and through a necessary middle term.
1. To that which is objected concerning the falsity of the conclusion, on the grounds that many have supposed there to be many gods: the response is now clear: because they use the supposit and signification of this term God otherwise than its institution warrants: and therefore there is no contradiction there. Whence, just as this name God according to its proper institution has no plural, although it does have one according as it is taken nuncupatively; so also in the present matter it is to be understood: and because on account of the blindness of the mind the false was frequently taken for the true, therefore the illumination of faith was necessary. - It could nevertheless be said that God is one can be proved by reason, insofar as His unity is considered absolutely: but the illumination of faith is necessary insofar as it is compared to the plurality of persons.
2. To the objection that they could similarly conclude regarding the persons: it must be said that it is not similar, because in all the persons there is one nature and power and wisdom and goodness and influence and causality; but it would not be so if there were diverse divine natures: and therefore multiple persons are in no way repugnant to these.
3. To the objection that the merit of faith is emptied: it must be said that this would be true if one assented to this truth solely on account of reasons: but now, since one does not assent principally on account of reasons, but on account of the truth itself, therefore it can have merit on account of faithful assent. For nothing prevents the same thing from being known and believed under different respects and considerations.
4. To the objection concerning sublimity with respect to great and similar beings: it must be said that this would hold if something accrued to the divine sublimity from the subjection of others; but this is not true, because God is just as sublime in Himself and existing alone as if He were lord over a thousand worlds.
Furthermore, it would not contribute to His sublimity if something of a similar nature had a servile condition: whence even if such sublimity might in some way seem to contribute to exaltation, nevertheless in truth it contributes to diminishment.
5. To the objection concerning power, it must be said that each statement can be understood regarding that which indeed to be able belongs to power. For a certain ability is rather of weakness than of sublimity: for to be able to have a nature equal to oneself yet differing from oneself, this belongs to the dignity of limited power, and thereby is repugnant to omnipotence; therefore, although it can be said in speech, it nevertheless cannot be attributed to God: nor is the magnitude of divine power measured according to the magnitude of this possible, but according to the dignity of His proper act, which is immense, inasmuch as His power is immense.
6. To the objection concerning wisdom, that He knows another: it must be said that although God knows another than Himself eternally, and this befits supreme wisdom, nevertheless it does not befit Him to know another through another, but through Himself; and this can only be if the other is something born to proceed from God Himself, which is in Him as in its originating principle. For even if evil is known by God, this is through the idea of the good opposed to it. Whence for the perfection of divine knowledge it is not required that the knowable be a being in act: nor is it required that it be a supreme being, since He knows earthly things most nobly and most perfectly through Himself. That, however, holds for knowledge which takes its origin from things, which kind of knowledge God does not have.
7. To that which is objected, that supreme diffusion and a multitude of goods belong to the supreme good: it must be said that supreme diffusion into something outside does not belong to it, according as supreme is said absolutely: but within, supreme communication does belong to it. For there ought to be only one supreme good, which indeed cannot be increased by a multitude of goods. Hence what is said, that the supreme good is supremely diffusive: this must be understood as having truth according as that supremely determines diffusive by reason of power, not by reason of act. And to what is said, that many goods are more to be chosen: it must be said that this has truth in finite goods, of which one adds to another, and of which each one lacks something of the good, which is supplied through the adjoined good.
8. To that which is objected concerning influence, that it cannot exist without God, therefore neither can it be multiplied: it must be said that this does not hold, nor is it similar: because it belongs to the perfection of the agent that the effect cannot exist without its presence, because it depends totally upon it, and the agent acts more nobly by acting immediately than through a medium. But it is not so concerning number and multitude. For it does not belong to the perfection of the agent that it be multiplied according to the multitude of effects, but rather its contrary, namely that remaining one in itself it be the cause of diverse things.
9. To that which is objected concerning the proximate and immediate cause, that it is multiplied: it must be said that this has truth in a cause acting by way of nature, whose power is also limited, and thus is a proper cause, but not a universal one. But the first cause acts by way of art and will in the production of creatures: and therefore it is a most free cause, limited to nothing, and at once both universal and proper, because whatever nobility is in the creature must necessarily be posited in the creative essence.
10. To that which is objected, that those are means for proving multitude and diversity: it must be said that they do not prove just any diversity in creatures, but diversity with order and connection and inclination toward unity, and thus diversity in unity, and by reason of that unity they infer unity in the cause; nor yet are they a way to opposites, because unity in the cause does not conflict with multitude in things caused, as is evident in unity, from which proceed infinite species of numbers. So also supreme wisdom and power and goodness, although they are one, yet because they are not sufficiently manifested through one effect, therefore they bring about diversity in effects caused by it. - And thus the response to all the objections is clear.
ARTICLE II.