QUESTION 3: OF THE SIMPLICITY OF GOD
When the existence of a thing has been ascertained there remains the
further question of the manner of its existence, in order that we may
know its essence. Now, because we cannot know what God is, but rather
what He is not, we have no means for considering how God is, but rather
how He is not.
Therefore, we must consider: (1) How He is not; (2) How He is known by
us; (3) How He is named.
Now it can be shown how God is not, by denying Him whatever is opposed
to the idea of Him, viz. composition, motion, and the like. Therefore (1)
we must discuss His simplicity, whereby we deny composition in Him; and
because whatever is simple in material things is imperfect and a part of
something else, we shall discuss (2) His perfection; (3) His infinity;
(4) His immutability; (5) His unity.
Concerning His simplicity, there are eight points of inquiry:
(1) Whether God is a body?
(2) Whether He is composed of matter and form?
(3) Whether in Him there is composition of quiddity, essence or nature,
(4) Whether He is composed of essence and existence?
(5) Whether He is composed of genus and difference?
(6) Whether He is composed of subject and accident?
(7) Whether He is in any way composite, or wholly simple?
(8) Whether He enters into composition with other things?
Article 1: Whether God is a body?
Objection 1: It seems that God is a body. For a body is that which has the
three dimensions. But Holy Scripture attributes the three dimensions to
God, for it is written: "He is higher than Heaven, and what wilt thou do?
He is deeper than Hell, and how wilt thou know? The measure of Him is
longer than the earth and broader than the sea" (Job 11:8,9). Therefore
God is a body.
Objection 2: Further, everything that has figure is a body, since figure is a
quality of quantity. But God seems to have figure, for it is written:
"Let us make man to our image and likeness" (Gn. 1:26). Now a figure is
called an image, according to the text: "Who being the brightness of His
glory and the figure," i.e. the image, "of His substance" (Heb. 1:3).
Therefore God is a body.
Objection 3: Further, whatever has corporeal parts is a body. Now Scripture
attributes corporeal parts to God. "Hast thou an arm like God?" (Job 40:4); and "The eyes of the Lord are upon the just" (Ps. 33:16); and "The
right hand of the Lord hath wrought strength" (Ps. 117:16). Therefore God
is a body.
Objection 4: Further, posture belongs only to bodies. But something which supposes posture is said of God in the Scriptures: "I saw the Lord sitting" (Is. 6:1), and "He standeth up to judge" (Is. 3:13). Therefore God is a body.
Objection 5: Further, only bodies or things corporeal can be a local term
"wherefrom" or "whereto." But in the Scriptures God is spoken of as a
local term "whereto," according to the words, "Come ye to Him and be
enlightened" (Ps. 33:6), and as a term "wherefrom": "All they that depart
from Thee shall be written in the earth" (Jer. 17:13). Therefore God is a
On the contrary, It is written in the Gospel of St. John (Jn. 4:24):
"God is a spirit."
I answer that, It is absolutely true that God is not a body; and this
can be shown in three ways. First, because no body is in motion unless it
be put in motion, as is evident from induction. Now it has been already
proved (Question , Article ), that God is the First Mover, and is Himself unmoved.
Therefore it is clear that God is not a body. Secondly, because the first
being must of necessity be in act, and in no way in potentiality. For
although in any single thing that passes from potentiality to actuality,
the potentiality is prior in time to the actuality; nevertheless,
absolutely speaking, actuality is prior to potentiality; for whatever is
in potentiality can be reduced into actuality only by some being in
actuality. Now it has been already proved that God is the First Being. It
is therefore impossible that in God there should be any potentiality. But
every body is in potentiality because the continuous, as such, is
divisible to infinity; it is therefore impossible that God should be a
body. Thirdly, because God is the most noble of beings. Now it is
impossible for a body to be the most noble of beings; for a body must be
either animate or inanimate; and an animate body is manifestly nobler
than any inanimate body. But an animate body is not animate precisely as
body; otherwise all bodies would be animate. Therefore its animation
depends upon some other thing, as our body depends for its animation on
the soul. Hence that by which a body becomes animated must be nobler than
the body. Therefore it is impossible that God should be a body.
Reply to Objection 1: As we have said above (Question , Article ), Holy Writ puts before
us spiritual and divine things under the comparison of corporeal things.
Hence, when it attributes to God the three dimensions under the
comparison of corporeal quantity, it implies His virtual quantity; thus,
by depth, it signifies His power of knowing hidden things; by height, the
transcendence of His excelling power; by length, the duration of His
existence; by breadth, His act of love for all. Or, as says Dionysius
(Div. Nom. ix), by the depth of God is meant the incomprehensibility of
His essence; by length, the procession of His all-pervading power; by
breadth, His overspreading all things, inasmuch as all things lie under
Reply to Objection 2: Man is said to be after the image of God, not as regards
his body, but as regards that whereby he excels other animals. Hence,
when it is said, "Let us make man to our image and likeness", it is
added, "And let him have dominion over the fishes of the sea" (Gn. 1:26). Now man excels all animals by his reason and intelligence; hence
it is according to his intelligence and reason, which are incorporeal,
that man is said to be according to the image of God.
Reply to Objection 3: Corporeal parts are attributed to God in Scripture on
account of His actions, and this is owing to a certain parallel. For
instance the act of the eye is to see; hence the eye attributed to God
signifies His power of seeing intellectually, not sensibly; and so on
with the other parts.
Reply to Objection 4: Whatever pertains to posture, also, is only attributed to
God by some sort of parallel. He is spoken of as sitting, on account of
His unchangeableness and dominion; and as standing, on account of His
power of overcoming whatever withstands Him.
Reply to Objection 5: We draw near to God by no corporeal steps, since He is
everywhere, but by the affections of our soul, and by the actions of that
same soul do we withdraw from Him; thus, to draw near to or to withdraw
signifies merely spiritual actions based on the metaphor of local motion.
Article 2: Whether God is composed of matter and form?
Objection 1: It seems that God is composed of matter and form. For whatever
has a soul is composed of matter and form; since the soul is the form of
the body. But Scripture attributes a soul to God; for it is mentioned in
Hebrews (Heb. 10:38), where God says: "But My just man liveth by faith;
but if he withdraw himself, he shall not please My soul." Therefore God
is composed of matter and form.
Objection 2: Further, anger, joy and the like are passions of the composite.
But these are attributed to God in Scripture: "The Lord was exceeding
angry with His people" (Ps. 105:40). Therefore God is composed of matter
Objection 3: Further, matter is the principle of individualization. But God
seems to be individual, for He cannot be predicated of many. Therefore He
is composed of matter and form.
On the contrary, Whatever is composed of matter and form is a body; for
dimensive quantity is the first property of matter. But God is not a body
as proved in the preceding Article; therefore He is not composed of
matter and form.
I answer that, It is impossible that matter should exist in God. First,
because matter is in potentiality. But we have shown (Question , Article ) that
God is pure act, without any potentiality. Hence it is impossible that
God should be composed of matter and form. Secondly, because everything
composed of matter and form owes its perfection and goodness to its form;
therefore its goodness is participated, inasmuch as matter participates
the form. Now the first good and the best---viz. God---is not a
participated good, because the essential good is prior to the
participated good. Hence it is impossible that God should be composed of
matter and form. Thirdly, because every agent acts by its form; hence the
manner in which it has its form is the manner in which it is an agent.
Therefore whatever is primarily and essentially an agent must be
primarily and essentially form. Now God is the first agent, since He is
the first efficient cause. He is therefore of His essence a form; and not
composed of matter and form.
Reply to Objection 1: A soul is attributed to God because His acts resemble the
acts of a soul; for, that we will anything, is due to our soul. Hence
what is pleasing to His will is said to be pleasing to His soul.
Reply to Objection 2: Anger and the like are attributed to God on account of a
similitude of effect. Thus, because to punish is properly the act of an
angry man, God's punishment is metaphorically spoken of as His anger.
Reply to Objection 3: Forms which can be received in matter are individualized by
matter, which cannot be in another as in a subject since it is the first
underlying subject; although form of itself, unless something else
prevents it, can be received by many. But that form which cannot be
received in matter, but is self-subsisting, is individualized precisely
because it cannot be received in a subject; and such a form is God. Hence
it does not follow that matter exists in God.
Article 3: Whether God is the same as His essence or nature?
Objection 1: It seems that God is not the same as His essence or nature. For
nothing can be in itself. But the substance or nature of God---i.e. the
Godhead---is said to be in God. Therefore it seems that God is not the
same as His essence or nature.
Objection 2: Further, the effect is assimilated to its cause; for every agent
produces its like. But in created things the "suppositum" is not
identical with its nature; for a man is not the same as his humanity.
Therefore God is not the same as His Godhead.
On the contrary, It is said of God that He is life itself, and not only
that He is a living thing: "I am the way, the truth, and the life" (Jn. 14:6). Now the relation between Godhead and God is the same as the
relation between life and a living thing. Therefore God is His very
I answer that, God is the same as His essence or nature. To understand
this, it must be noted that in things composed of matter and form, the
nature or essence must differ from the "suppositum," because the essence
or nature connotes only what is included in the definition of the
species; as, humanity connotes all that is included in the definition of
man, for it is by this that man is man, and it is this that humanity
signifies, that, namely, whereby man is man. Now individual matter, with
all the individualizing accidents, is not included in the definition of
the species. For this particular flesh, these bones, this blackness or
whiteness, etc., are not included in the definition of a man. Therefore
this flesh, these bones, and the accidental qualities distinguishing this
particular matter, are not included in humanity; and yet they are
included in the thing which is man. Hence the thing which is a man has
something more in it than has humanity. Consequently humanity and a man
are not wholly identical; but humanity is taken to mean the formal part
of a man, because the principles whereby a thing is defined are regarded
as the formal constituent in regard to the individualizing matter. On the
other hand, in things not composed of matter and form, in which
individualization is not due to individual matter---that is to say, to
"this" matter---the very forms being individualized of themselves---it is
necessary the forms themselves should be subsisting "supposita."
Therefore "suppositum" and nature in them are identified. Since God then
is not composed of matter and form, He must be His own Godhead, His own
Life, and whatever else is thus predicated of Him.
Reply to Objection 1: We can speak of simple things only as though they were like
the composite things from which we derive our knowledge. Therefore in
speaking of God, we use concrete nouns to signify His subsistence,
because with us only those things subsist which are composite; and we use
abstract nouns to signify His simplicity. In saying therefore that
Godhead, or life, or the like are in God, we indicate the composite way
in which our intellect understands, but not that there is any composition
Reply to Objection 2: The effects of God do not imitate Him perfectly, but only
as far as they are able; and the imitation is here defective, precisely
because what is simple and one, can only be represented by divers things;
consequently, composition is accidental to them, and therefore, in them
"suppositum" is not the same as nature.
Article 4: Whether essence and existence are the same in God?
Objection 1: It seems that essence and existence are not the same in God. For
if it be so, then the divine being has nothing added to it. Now being to
which no addition is made is universal being which is predicated of all
things. Therefore it follows that God is being in general which can be
predicated of everything. But this is false: "For men gave the
incommunicable name to stones and wood" (Wis. 14:21). Therefore God's
existence is not His essence.
Objection 2: Further, we can know "whether" God exists as said above (Question , Article ); but we cannot know "what" He is. Therefore God's existence is not
the same as His essence---that is, as His quiddity or nature.
On the contrary, Hilary says (Trin. vii): "In God existence is not an
accidental quality, but subsisting truth." Therefore what subsists in God
is His existence.
I answer that, God is not only His own essence, as shown in the
preceding article, but also His own existence. This may be shown in
several ways. First, whatever a thing has besides its essence must be
caused either by the constituent principles of that essence (like a
property that necessarily accompanies the species---as the faculty of
laughing is proper to a man---and is caused by the constituent principles
of the species), or by some exterior agent---as heat is caused in water
by fire. Therefore, if the existence of a thing differs from its essence,
this existence must be caused either by some exterior agent or by its
essential principles. Now it is impossible for a thing's existence to be
caused by its essential constituent principles, for nothing can be the
sufficient cause of its own existence, if its existence is caused.
Therefore that thing, whose existence differs from its essence, must have
its existence caused by another. But this cannot be true of God; because
we call God the first efficient cause. Therefore it is impossible that in
God His existence should differ from His essence. Secondly, existence is
that which makes every form or nature actual; for goodness and humanity
are spoken of as actual, only because they are spoken of as existing.
Therefore existence must be compared to essence, if the latter is a
distinct reality, as actuality to potentiality. Therefore, since in God
there is no potentiality, as shown above (Article ), it follows that in Him
essence does not differ from existence. Therefore His essence is His
existence. Thirdly, because, just as that which has fire, but is not
itself fire, is on fire by participation; so that which has existence but
is not existence, is a being by participation. But God is His own
essence, as shown above (Article ) if, therefore, He is not His own existence
He will be not essential, but participated being. He will not therefore
be the first being---which is absurd. Therefore God is His own existence,
and not merely His own essence.
Reply to Objection 1: A thing that has nothing added to it can be of two kinds.
Either its essence precludes any addition; thus, for example, it is of
the essence of an irrational animal to be without reason. Or we may
understand a thing to have nothing added to it, inasmuch as its essence
does not require that anything should be added to it; thus the genus
animal is without reason, because it is not of the essence of animal in
general to have reason; but neither is it to lack reason. And so the
divine being has nothing added to it in the first sense; whereas
universal being has nothing added to it in the second sense.
Reply to Objection 2: "To be" can mean either of two things. It may mean the act
of essence, or it may mean the composition of a proposition effected by
the mind in joining a predicate to a subject. Taking "to be" in the first
sense, we cannot understand God's existence nor His essence; but only in
the second sense. We know that this proposition which we form about God
when we say "God is," is true; and this we know from His effects (Question , Article ).
Article 5: Whether God is contained in a genus?
Objection 1: It seems that God is contained in a genus. For a substance is a
being that subsists of itself. But this is especially true of God.
Therefore God is in a genus of substance.
Objection 2: Further, nothing can be measured save by something of its own
genus; as length is measured by length and numbers by number. But God is
the measure of all substances, as the Commentator shows (Metaph. x).
Therefore God is in the genus of substance.
On the contrary, In the mind, genus is prior to what it contains. But
nothing is prior to God either really or mentally. Therefore God is not
in any genus.
I answer that, A thing can be in a genus in two ways; either absolutely
and properly, as a species contained under a genus; or as being reducible
to it, as principles and privations. For example, a point and unity are
reduced to the genus of quantity, as its principles; while blindness and
all other privations are reduced to the genus of habit. But in neither
way is God in a genus. That He cannot be a species of any genus may be
shown in three ways. First, because a species is constituted of genus and
difference. Now that from which the difference constituting the species
is derived, is always related to that from which the genus is derived, as
actuality is related to potentiality. For animal is derived from
sensitive nature, by concretion as it were, for that is animal, which has
a sensitive nature. Rational being, on the other hand, is derived from
intellectual nature, because that is rational, which has an intellectual
nature, and intelligence is compared to sense, as actuality is to
potentiality. The same argument holds good in other things. Hence since
in God actuality is not added to potentiality, it is impossible that He
should be in any genus as a species. Secondly, since the existence of God
is His essence, if God were in any genus, He would be the genus "being",
because, since genus is predicated as an essential it refers to the
essence of a thing. But the Philosopher has shown (Metaph. iii) that
being cannot be a genus, for every genus has differences distinct from
its generic essence. Now no difference can exist distinct from being; for
non-being cannot be a difference. It follows then that God is not in a
genus. Thirdly, because all in one genus agree in the quiddity or essence
of the genus which is predicated of them as an essential, but they differ
in their existence. For the existence of man and of horse is not the
same; as also of this man and that man: thus in every member of a genus,
existence and quiddity---i.e. essence---must differ. But in God they do
not differ, as shown in the preceding article. Therefore it is plain that
God is not in a genus as if He were a species. From this it is also plain
that He has no genus nor difference, nor can there be any definition of
Him; nor, save through His effects, a demonstration of Him: for a
definition is from genus and difference; and the mean of a demonstration
is a definition. That God is not in a genus, as reducible to it as its
principle, is clear from this, that a principle reducible to any genus
does not extend beyond that genus; as, a point is the principle of
continuous quantity alone; and unity, of discontinuous quantity. But God
is the principle of all being. Therefore He is not contained in any genus
as its principle.
Reply to Objection 1: The word substance signifies not only what exists of
itself---for existence cannot of itself be a genus, as shown in the body
of the article; but, it also signifies an essence that has the property
of existing in this way---namely, of existing of itself; this existence,
however, is not its essence. Thus it is clear that God is not in the
genus of substance.
Reply to Objection 2: This objection turns upon proportionate measure which must
be homogeneous with what is measured. Now, God is not a measure
proportionate to anything. Still, He is called the measure of all things,
in the sense that everything has being only according as it resembles Him.
Article 6: Whether in God there are any accidents?
Objection 1: It seems that there are accidents in God. For substance cannot be
an accident, as Aristotle says (Phys. i). Therefore that which is an
accident in one, cannot, in another, be a substance. Thus it is proved
that heat cannot be the substantial form of fire, because it is an
accident in other things. But wisdom, virtue, and the like, which are
accidents in us, are attributes of God. Therefore in God there are
Objection 2: Further, in every genus there is a first principle. But there are
many "genera" of accidents. If, therefore, the primal members of these
genera are not in God, there will be many primal beings other than
God---which is absurd.
On the contrary, Every accident is in a subject. But God cannot be a
subject, for "no simple form can be a subject", as Boethius says (De
Trin.). Therefore in God there cannot be any accident.
I answer that, From all we have said, it is clear there can be no
accident in God. First, because a subject is compared to its accidents as
potentiality to actuality; for a subject is in some sense made actual by
its accidents. But there can be no potentiality in God, as was shown
(Question , Article ). Secondly, because God is His own existence; and as Boethius
says (Hebdom.), although every essence may have something superadded to
it, this cannot apply to absolute being: thus a heated substance can have
something extraneous to heat added to it, as whiteness, nevertheless
absolute heat can have nothing else than heat. Thirdly, because what is
essential is prior to what is accidental. Whence as God is absolute
primal being, there can be in Him nothing accidental. Neither can He have
any essential accidents (as the capability of laughing is an essential
accident of man), because such accidents are caused by the constituent
principles of the subject. Now there can be nothing caused in God, since
He is the first cause. Hence it follows that there is no accident in God.
Reply to Objection 1: Virtue and wisdom are not predicated of God and of us
univocally. Hence it does not follow that there are accidents in God as
there are in us.
Reply to Objection 2: Since substance is prior to its accidents, the principles
of accidents are reducible to the principles of the substance as to that
which is prior; although God is not first as if contained in the genus of
substance; yet He is first in respect to all being, outside of every
Article 7: Whether God is altogether simple?
Objection 1: It seems that God is not altogether simple. For whatever is from
God must imitate Him. Thus from the first being are all beings; and from
the first good is all good. But in the things which God has made, nothing
is altogether simple. Therefore neither is God altogether simple.
Objection 2: Further, whatever is best must be attributed to God. But with us
that which is composite is better than that which is simple; thus,
chemical compounds are better than simple elements, and animals than the
parts that compose them. Therefore it cannot be said that God is
On the contrary, Augustine says (De Trin. iv, 6,7): "God is truly and
I answer that, The absolute simplicity of God may be shown in many ways.
First, from the previous articles of this question. For there is neither
composition of quantitative parts in God, since He is not a body; nor
composition of matter and form; nor does His nature differ from His
"suppositum"; nor His essence from His existence; neither is there in Him
composition of genus and difference, nor of subject and accident.
Therefore, it is clear that God is nowise composite, but is altogether
simple. Secondly, because every composite is posterior to its component
parts, and is dependent on them; but God is the first being, as shown
above (Question , Article ). Thirdly, because every composite has a cause, for
things in themselves different cannot unite unless something causes them
to unite. But God is uncaused, as shown above (Question , Article ), since He is
the first efficient cause. Fourthly, because in every composite there
must be potentiality and actuality; but this does not apply to God; for
either one of the parts actuates another, or at least all the parts are
potential to the whole. Fifthly, because nothing composite can be
predicated of any single one of its parts. And this is evident in a whole
made up of dissimilar parts; for no part of a man is a man, nor any of
the parts of the foot, a foot. But in wholes made up of similar parts,
although something which is predicated of the whole may be predicated of
a part (as a part of the air is air, and a part of water, water),
nevertheless certain things are predicable of the whole which cannot be
predicated of any of the parts; for instance, if the whole volume of
water is two cubits, no part of it can be two cubits. Thus in every
composite there is something which is not it itself. But, even if this
could be said of whatever has a form, viz. that it has something which is
not it itself, as in a white object there is something which does not
belong to the essence of white; nevertheless in the form itself, there is
nothing besides itself. And so, since God is absolute form, or rather
absolute being, He can be in no way composite. Hilary implies this
argument, when he says (De Trin. vii): "God, Who is strength, is not made
up of things that are weak; nor is He Who is light, composed of things
that are dim."
Reply to Objection 1: Whatever is from God imitates Him, as caused things imitate
the first cause. But it is of the essence of a thing to be in some sort
composite; because at least its existence differs from its essence, as
will be shown hereafter, (Question , Article ).
Reply to Objection 2: With us composite things are better than simple things,
because the perfections of created goodness cannot be found in one simple
thing, but in many things. But the perfection of divine goodness is found
in one simple thing (Question , Article  and Question , Article ).
Article 8: Whether God enters into the composition of other things?
Objection 1: It seems that God enters into the composition of other things,
for Dionysius says (Coel. Hier. iv): "The being of all things is that
which is above being---the Godhead." But the being of all things enters
into the composition of everything. Therefore God enters into the
composition of other things.
Objection 2: Further, God is a form; for Augustine says (De Verb. Dom.,
[*Serm. xxxviii]) that, "the word of God, which is God, is an uncreated
form." But a form is part of a compound. Therefore God is part of some
Objection 3: Further, whatever things exist, in no way differing from each
other, are the same. But God and primary matter exist, and in no way
differ from each other. Therefore they are absolutely the same. But
primary matter enters into the composition things. Therefore also does
God. Proof of the minor---whatever things differ, they differ by some
differences, and therefore must be composite. But God and primary matter
are altogether simple. Therefore they nowise differ from each other.
On the contrary, Dionysius says (Div. Nom. ii): "There can be no
touching Him," i.e. God, "nor any other union with Him by mingling part
Further, the first cause rules all things without commingling with them, as the Philosopher says (De Causis).
I answer that, On this point there have been three errors. Some have
affirmed that God is the world-soul, as is clear from Augustine (De Civ.
Dei vii, 6). This is practically the same as the opinion of those who
assert that God is the soul of the highest heaven. Again, others have
said that God is the formal principle of all things; and this was the
theory of the Almaricians. The third error is that of David of Dinant,
who most absurdly taught that God was primary matter. Now all these
contain manifest untruth; since it is not possible for God to enter into
the composition of anything, either as a formal or a material principle.
First, because God is the first efficient cause. Now the efficient cause
is not identical numerically with the form of the thing caused, but only
specifically: for man begets man. But primary matter can be neither
numerically nor specifically identical with an efficient cause; for the
former is merely potential, while the latter is actual. Secondly,
because, since God is the first efficient cause, to act belongs to Him
primarily and essentially. But that which enters into composition with
anything does not act primarily and essentially, but rather the composite
so acts; for the hand does not act, but the man by his hand; and, fire
warms by its heat. Hence God cannot be part of a compound. Thirdly,
because no part of a compound can be absolutely primal among beings---not
even matter, nor form, though they are the primal parts of every
compound. For matter is merely potential; and potentiality is absolutely
posterior to actuality, as is clear from the foregoing (Question , Article ):
while a form which is part of a compound is a participated form; and as
that which participates is posterior to that which is essential, so
likewise is that which is participated; as fire in ignited objects is
posterior to fire that is essentially such. Now it has been proved that
God is absolutely primal being (Question , Article ).
Reply to Objection 1: The Godhead is called the being of all things, as their
efficient and exemplar cause, but not as being their essence.
Reply to Objection 2: The Word is an exemplar form; but not a form that is part
of a compound.
Reply to Objection 3: Simple things do not differ by added differences---for this
is the property of compounds. Thus man and horse differ by their
differences, rational and irrational; which differences, however, do not
differ from each other by other differences. Hence, to be quite accurate,
it is better to say that they are, not different, but diverse. Hence,
according to the Philosopher (Metaph. x), "things which are diverse are
absolutely distinct, but things which are different differ by something."
Therefore, strictly speaking, primary matter and God do not differ, but
are by their very being, diverse. Hence it does not follow they are the