Question 11: The Unity of God
WHETHER GOD IS ONE
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
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)
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."
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.