"The good of the grace of one soul is greater than the good of the nature of the whole universe"
- St Thomas Aquinas Ia IIa, q.24, a. 3, ad 2

— A Commentary on the First Part of St Thomas' Theological Summa

by Reginald Garrigou-Lagrange, O. P.


Question 11: The Unity of God



State of the question. The discussion is not about the absence of division in God for we have already seen, when treating of God's simplicity,(18) that He is absolutely indivisible since there is no kind of composition in Him, either physical, metaphysical, or logical. But the discussion concerns God's unicity. A being, however is, said to be unique, when there cannot be or at least are not other beings of the same species or genus. Therefore God is unique, if there cannot be many Gods. But, as we shall at once see, unicity has its foundation in unity, and God's unicity in the absolute indivisibility of the Deity.

It must be noted that all polytheists denied God's unity, and likewise many heretics who admitted two principles, one of good and the other of evil, such as the Gnostics, the Marcionites, the Valentinians of the second century. Along with these we must include the Manichaeans of the third century, and finally the Albigensians of the thirteenth century. In the sixteenth century, too, the Tritheists, not having a proper conception of the real distinction between the three divine Persons, spoke as if there were three Gods.

Finally, the pantheists implicitly deny God's unity, inasmuch as they admit a necessity of emanation of the divine nature in its external communication, just as the sun's rays of necessity proceed from it. St. Thomas gives three reasons for idolatry or polytheism: (i) an excessive love for certain men, who were the objects of veneration; (2) ignorance of the true God; (3) demoniacal inspiration.

Reply. There is of necessity but one God.

1. This conclusion is of faith, as clearly seen from very many texts of Holy Scripture; e.g., "Hear, 0 Israel, the Lord our God is one Lord." (19) There is scarcely a page of the Old or New Testament in which there is not a reference to monotheism. Likewise the first words of the Nicene Creed are: "I believe in one God." The Fourth Lateran Council says: "We firmly believe that there is only one true God ... the one principle of all things." (20) This same truth is equivalently expressed in the Vatican Counci1.(21)

2. Three proofs from reason are given of God's unicity. It is proved: (1) from God's simplicity; (2) from His infinity; (3) from the unity and order in the world. It is proved from God's simplicity as follows: It is impossible to communicate to many that which any singular thing is this particular thing, for instance, that by which Socrates is this particular man as distinct from others. But because Socrates is not humanity, there can be many men. Since God, however, is His Deity, for the same reason He is both God and this God. Therefore it is impossible that there
should be many Gods.

This reasoning is clear, and is made clearer by contrasting it with its opposite, when it is said: "If Socrates were a man by what makes him to be this particular man, as there cannot be many Socrates, so there could not be many men." Hence, because in the same way God is God and this God, there cannot be many Gods.

For the understanding of the major, it must be noted that this whereby any singular thing is this particular thing cannot be communicated to many, whether we are speaking of individuality resulting from matter which is the foundation of quantity, or whether we are speaking of subsistence or of personality. Indeed, matter which is the foundation of quantity cannot be communicated to inferior things, that is, it cannot be participated by another subject, since matter is the ultimate subject and pure potency, capable of receiving but not of being received. But if we consider subsistence or personality, then that by which this particular thing cannot be communicated is that by which the nature is made incommunicable to another suppositum or person. Therefore in these two acceptations of the term "singularity" we have the verification of the major.

The minor, however, has its foundation in the truth that God is His own Godhead,(22) which means that there is no distinction between either the Godhead and this Godhead (because Godhead is not a form received in matter), or between this Godhead and this God (because God is absolutely simple, and He does not constitute a whole of which the Godhead would be only an essential part).

On the other hand, although there is not any distinction between Michaelness and this Michaelness, Michael is not his Michaelness, because Michael represents the whole, of which Michaelness is the essential part, and besides this there is in Michael contingent existence and accidents.

Moreover, in contradistinction to the Godhead, the angelic nature taken generically can be communicated to many, inasmuch as there can be many subordinated angelic species according to the perfections of their intellectual power. But this plurality does not apply to the Godhead, for this is not only separated from matter, but transcends every species and genus.(23) From this first proof it is clear that God's unicity is deduced from His unity, and from His simplicity or indivisibility.

The second proof is derived from God's infinity.

There cannot be two or many infinitely perfect beings. But God is the infinitely perfect being as stated above.(24) Consequently, there cannot be many Gods.

Proof of major. If there were two infinitely perfect beings, there would have to be a difference between them, and this difference would have to be a perfection and not an imperfection. Hence a certain "perfection would be wanting to one of them." This means that each of them would have to be the self-subsisting Being, and then there would be no way of distinguishing between them, either on our part or in themselves. In other words, there is only one unreceived subsisting Being, just as there would necessarily be but one whiteness, if this were not received in anything. On the other hand, there is a real distinction between God and creatures, inasmuch as these are not their existence, and this, being an imperfection, cannot be in the infinitely perfect Being.

From this proof given by St. Thomas many Thomists deduce that the subsistent relations in the divine Persons, according as they denote regard to another (esse ad), are not absolutely simple perfections, for since filiation is not in the Father, He would be without some absolutely simple perfection and thus would not be God. For an absolutely simple perfection not only implies no imperfection, but it is better for one to have than not to have this. Hence the divine relations, according as they denote regard to another (esse ad), do not add a new perfection to the infinite perfection of the divine nature. The same is to be said of God's free act, for instance, the creative free act.

The third proof is derived from the unity of the universe, and thus the fifth way of proving God's existence is perfected from on high.

Things that are diverse do not harmonize in the same order, unless they are ordered thereto by one, because one is essentially the cause of one. But there is ordination, either of subordination or of coordination, between all existing things in the universe. Therefore all these things are ordered by the one, which must be most perfect, so that all things may be ordered by it. And this one is God.

The major is evident from what we said about unity and multitude; for multitude does not convey the idea of unity that is found in it.(26) There must be an intelligent Ordainer, for He must perceive the reasons for the existence of things, and the means in the end. Moreover, He must be the self-subsisting Intellection, otherwise His intelligence would be ordered to intellection and truth by a higher Ordainer. But there must be only one self-subsisting Intellection, just as there is only one self-subsisting Being.(27)

Reply to second objection. God is said to be one or undivided by a privation of division. But this privation is only according to our mode of apprehension because with us the concept of the composite is prior to that of the simple. Hence we define a point to be "what has no part." (28)


Index Top


18. Summa theol., Ia, q.3

19. Deut. 6: 4.

20. Denz., no. 428.

21. Ibid., nos. 1782, 1801.

22. Summa theol., Ia, q.3, a.3.

23. Ibid., q. 3, a. 5.

24. Ibid., q.q, a.3.

25. Ibid., q. 2, a.3.

26. See above, q.2, a. 3, fifth way.



"Lord, here burn, here cut, and dry up in me all that hinders me from going to You, that You may spare me in eternity."

St Louis Bertrand

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"It is better to be burdened and in company with the strong than to be unburdened and with the weak. When you are burdened you are close to God, your strength, who abides with the afflicted. When you are relieved of the burden you are close to yourself, your own weakness; for virtue and strength of soul grow and are confirmed in the trials of patience."

St John of the Cross, OCD - Doctor of the Church

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"A person who rails at God in adversity, suffers without merit; moreover by his lack of resignation he adds to his punishment in the next life and experiences greater disquietude of mind in this life."

St Alphonsus de Liguori

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