Thomas Aquinas
Thomas Aquinas
Brian Davies OP
Thomas Aquinas, son of Landulf d’Aquino and his wife Theodora,
was born sometime between 1224 and 1226 in what was then the
Kingdom of Naples.1 After a childhood education at the Benedictine
monastery of Monte Cassino, he studied at the university of Naples.
Here, possibly under Irish influence, he encountered the philosophy of
Aristotle, which subsequently became a major source of philosophical
inspiration to him.2 The thinking of Aristotle and Aquinas differ in
many ways. So it would be wrong to say, as some have, that Aquinas is
just an ‘Aristotelian’, implying that he merely echoed Aristotle.3 But he
certainly used Aristotle to help him say much that he wanted to say for
himself. And he did more than any other medieval philosopher to make
subsequent generations aware of the importance of Aristotle.
In 1242 or 1243 Aquinas entered the Dominican Order of preaching
friars founded by St Dominic (c. 1170–1221).4 He subsequently studied
under St Albert the Great (c. 1200–80) in Cologne and Paris, and by
1256 he was a professor at the University of Paris. The rest of his life
was devoted to teaching, preaching, administration and writing—not
only in Paris, but elsewhere as well. He taught, for example, at Orvieto
and Rome. He was assigned to establish a house of studies in Rome in
1265. In 1272 he moved to Naples, where he became responsible for
studies at the priory of San Domenico. But by 1274 his working life
was over. In December 1273 he suffered some kind of breakdown. At
around the same time he was asked to attend the second Council of
Lyons. He set out for Lyons, but he became seriously ill on the way
and he died in the Cistercian Abbey of Fossanova.
After his death Aquinas came near to being condemned at the
University of Paris. And teachings thought to derive from him were
condemned at Oxford in 1277. But his standing as a thinker grew
steadily and, in spite of continued opposition to his teaching, he was
canonized as a saint of the Catholic Church in 1323. Later medieval
authors often quote him and discuss him, and, though his influence
waned between the later medieval period and the age of the Counter-
Reformation, his impact on post-Reformation figures was considerable,
chiefly because St Ignatius Loyola arranged for his writings to be used
in the training of Jesuits. After another period in which his thinking
came to be lightly regarded, the study of Aquinas was encouraged by
the papacy in the nineteenth century.
PHILOSOPHER OR THEOLOGIAN?
Does Aquinas deserve a place in a book on the history of philosophy?
Anthony Kenny has described him as ‘one of the dozen greatest
philosophers of the western world’ ([11.27] 1). But others have
expressed a different view. Take, for example, Bertrand Russell.
According to him:
There is little of the true philosophic spirit in Aquinas. He
does not, like the Platonic Socrates, set out to follow
wherever the argument may lead. He is not engaged in an
inquiry, the result of which it is impossible to know in
advance. Before he begins to philosophize, he already knows
the truth; it is declared in the Catholic faith.5
Russell had little time for Aquinas considered as a philosopher. And
even Aquinas’s supporters have sometimes characterized him as a
theologian rather than a philosopher. According to Etienne Gilson, the
philosophy in Aquinas is indistinguishable from the theology.6 The
same opinion is expressed by Armand Maurer. Commenting on
Aquinas’s Summa theologiae, he says that, in this work,
everything is theological, even the philosophical reasoning
that makes up such a large part of it. The water of
philosophy and the other secular disciplines it contains has
been changed into the wine of theology. That is why we
cannot extract from the Summa its philosophical parts and
treat them as pure philosophy.7
Russell’s judgement will strike most modern philosophers as a dubious
one. And, as Kenny nicely observes, it ‘comes oddly from a philosopher
who [in Principia Mathematica] took three hundred and sixty dense
pages to offer a proof that 1+1=2’ ([11.27] 2). But there are good
reasons for agreeing with Gilson and Maurer. Aquinas was a priest
and a Dominican friar. And most of his writings can be properly classed
as ‘theology’. We have reason to believe that his greatest literary
achievement, the Summa theologiae, was chiefly intended as a textbook
for working friars.8 And there is reason to suppose that his second
best-known work, the Summa contra Gentiles, had an equally pastoral
and Christian motive.9
Yet any modern philosopher who reads Aquinas will be struck by
the fact that he was more than your average theologian. His writings
show him to have been expert in matters of philosophical logic. And,
like many medieval theology teachers, he presented his theology with
an eye, not just on Scripture and the authority of Christian tradition,
but also on what follows from what, what it is per se reasonable to
believe, and what it makes sense to say in general. If Aquinas is first
and foremost a theologian, he is also a philosopher’s theologian who
is worthy of attention from philosophers. He had an enviable knowledge
of philosophical writings and he was deeply concerned to theologize
on the basis of this knowledge. He was also a writer of considerable
ability with theses of his own, which are not just restatements of
positions received from the Christian tradition and the history of
philosophy. Whether one calls him a ‘theological’ thinker or a
‘philosophical’ thinker does not really matter. The fact remains that
his writings are full of philosophical interest.
AQUINAS AND GOD
Readers who want to get an overall sense of Aquinas’s teaching are
best advised to see it as defending what is usually called an exitusreditus
picture of reality ([11.12] ch. 11). God, says Aquinas, is ‘the beginning
and end of all things’.10 Creatures derive from God (exitus), who is
therefore their first efficient cause (that which accounts for them being
there).11 But God is also the final cause of creatures, that to which they
aim, tend, or return (reditus), that which contains the perfection or
goal of all created things.12 According to Aquinas, everything comes
from God and is geared to him. God accounts for there being anything
apart from himself, and he is what is aimed at by anything moving
towards its perfection. Aristotle says that everything aims for its good
(Ethics I, i, 1094a3). Aquinas says that any created good derives from
God who contains in himself all the perfections found in creatures. In
so far as a creature moves to its perfection, Aquinas goes on to argue,
the creature is tending to what is to be found in God himself.13 As
Father, Son, and Spirit, Aquinas adds, God is the special goal of rational
individuals. For these can share in what God is by nature.14
Aquinas is sometimes reported as teaching that someone who claims
rationally to believe in the existence of God must be able to prove that
God exists. But this is not what Aquinas teaches. He says that people
can have a rational belief in the existence of God without being able to
prove God’s existence.15 And he holds that, apart from the question of
God’s existence, people may be rational in believing what they cannot
prove. Following Aristotle, he maintains that people may rationally
believe indemonstrable principles of logic.16 He also maintains that
one may rationally believe what a teacher imparts to one, even though
one is in no position to demonstrate the truth of what the teacher has
told one.17 He does, however, contend that belief in God’s existence is
one for which good philosophical reasons can be given. This is clear
from Summa theologiae Ia, 2, 2 and Summa contra Gentiles I, 9, where
he says that ‘we can demonstrate…that God exists’ and that God can
be made known as we ‘proceed through demonstrative arguments’.
‘Demonstrative arguments’ here means what it does for Aristotle, i.e.
arguments using premisses which entail a given conclusion on pain of
contradiction.
Aquinas denies that proof of God’s existence is given by arguing
that ‘God does not exist’ is a contradiction. So he rejects the suggestion,
commonly associated with St Anselm, that the existence of God can be
demonstrated from the absurdity of denying that God exists.18 He also
rejects the view that human beings are naturally capable of perceiving
or experiencing God as they perceive or experience the things with
which they are normally acquainted. According to Aquinas, our
perception and seeing of things is based on sensory experience.19 Since
God is not a physical object, Aquinas concludes that there can be no
natural perception or seeing of God on the part of human beings.20 He
does not deny that people might have a knowledge of God without the
medium of physical objects. In talking of life after death, he says that
people can have a vision of God which is nothing like knowing a
physical object.21 But he denies that human beings in this world have a
direct and unmediated knowledge of God. On his account, our
knowledge of God starts from what we know of the world in which
we live. According to him, we can know that God exists because the
world in which we find ourselves cannot account for itself.
Aquinas considers whether we can prove that God exists in many
places in his writings. But his best-known arguments for the existence
of God come in Ia, 2, 3 (the ‘Five Ways’). His thinking in this text is
clearly indebted to earlier authors, especially Aristotle, Maimonides,
Avicenna and Averroes.22 And it would be foolish to suggest that the
reasoning of the Five Ways can be quickly summarized in a way that
does them justice. But their substance can be indicated in fairly
uncomplicated terms.
In general, Aquinas’s Five Ways employ a simple pattern of argument.
Each begins by drawing attention to some general feature of things
known to us on the basis of experience. It is then suggested that none
of these features can be accounted for in ordinary mundane terms, and
that we must move to a level of explanation which transcends any
with which we are familiar.23
Another way of putting it is to say that, according to the Five Ways,
questions we can raise with respect to what we encounter in day to
day life raise further questions the answer to which can only be thought
of as lying beyond what we encounter.
Take, for example, the First Way, in which the influence of Aristotle
is particularly prevalent.24 Here the argument starts from change or
motion in the world.25 It is clear, says Aquinas, that there is such a
thing—he cites as an instance the change involved in wood becoming
hot when subjected to fire.26 How, then, may we account for it?
According to Aquinas, anything changed or moved is changed or
moved by something else. Omne quod movetur ab alio movetur. This,
he reasons, is because a thing which has changed has become what it
was not to begin with, which can only happen if there is something
from which the reality attained by the thing as changed somehow
derives.27 Therefore, he concludes, there must be a first cause of things
being changed or moved. For there cannot be an endless series of things
changed or moved by other things. If every change in a series of
connected changes depends on a prior changer, the whole system of
changing things is only derivatively an initiator of change and still
requires something to initiate its change. There must be something
which causes change or motion in things without itself being changed
or moved by anything. There must an unchanged changer or an
unmoved mover.
Anything which is moved is moved by something else… To
cause motion is to bring into being what was previously only
able to be, and this can only be done by something that
already is… Now the same thing cannot at the same time be
both actually x and potentially x, though it can be actually x
and potentially y: the actually hot cannot at the same time be
potentially hot, though it can be potentially cold.
Consequently, a thing which is moved cannot itself cause
that same movement; it cannot move itself. Of necessity
therefore anything moved is moved by something else…
Now we must stop somewhere, otherwise there will be no
first cause of the movement and as a result no subsequent
causes… Hence one is bound to arrive at some first cause of
things being moved which is not itself moved by anything,
and this is what everybody understands by God.
(Summa theologiae I q. 2, a. 3)
If we bear in mind that Aquinas believes that time can be said to exist
because changes occur, the First Way is arguing that the reality of time
is a reason for believing in God.28 Aquinas is suggesting that the present
becomes the past because something non-temporal enables the present
to become past.
The pattern of the First Way is repeated in the rest of the Five Ways.
According to the Second Way, there are causes in the world which
bring it about that other things come to be. There are, as Aquinas puts
it, causes which are related as members of a series. In that case, however,
there must be a first cause, or something which is not itself caused to
be by anything. For causes arranged in series must have a first member.
In the observable world causes are found to be ordered in
series; we never observe, nor ever could, something causing
itself, for this would mean it preceded itself, and this is not
possible. Such a series of causes must however stop
somewhere; for in it an earlier member causes an intermediate
and the intermediate a last… Now if you eliminate a cause
you also eliminate its effects, so that you cannot have a last
cause, nor an intermediate one, unless you have a first.
(ibid.)
According to the Third Way29 there are things which are perishable
(e.g. plants) and things which are imperishable (in Aquinas’s language,
imperishable things are ‘necessary’ beings or things which ‘must be’).30
But why should this be so? The answer, says Aquinas, has to lie in
something imperishable and dependent for its existence on nothing.31
Now a thing that must be, may or may not owe this necessity
to something else. But just as we must stop somewhere in a
series of causes, so also in the series of things which must be
and owe this to other things.
(ibid.)
In the Fourth and Fifth Ways Aquinas turns to different questions.
Why are there things with varying degrees of perfection?32 And how
does it come about that in nature there are things which, while not
themselves intelligent, operate in a regular or goal-directed way?33
Aquinas suggests that perfections in things imply a source of perfections.
He thinks that where there are degrees of a perfection there must be
something which maximally embodies that perfection and which causes
it to occur in other things. And he thinks that the goal-directed activity
of non-rational things suggests that they are governed by what is
rational.
Some things are found to be more good, more true, more noble,
and so on, and other things less. But such comparative terms
describe varying degrees of approximation to a superlative; for
example, things are hotter and hotter the nearer they approach
to what is hottest. Something therefore is the truest and best
and most noble of things. Now when many things possess some
property in common, the one most fully possessing it causes it
in the others: fire, to use Aristotle’s example, the hottest of all
things, causes all other things to be hot. There is therefore
something which causes in all other things their being, their
goodness, and whatever other perfections they have.
Some things which lack awareness, namely bodies, operate in
accordance with an end… Nothing however that lacks
awareness tends to a goal except under the direction of
someone with awareness and with understanding…
Everything in nature, therefore is directed to its goal by
someone with understanding.
(ibid.)
WHAT IS GOD LIKE?
Aquinas is often described as someone who first tries to prove the
existence of God and then tries to show that God has various attributes.
But, though this description can be partly defended, it is also misleading.
For Aquinas holds that the attributes we ascribe to God are not, in
reality, anything distinct from God himself. According to Aquinas, God
is good, perfect, knowledgeable, powerful and eternal. But he does not
think that, for example, ‘the goodness of God’ signifies anything other
than God himself. In the thinking of Aquinas, God does not have
attributes or properties. God is his attributes or properties.34 Aquinas
also maintains that, though we speak of God and ascribe certain
attributes to him, we do not know what God is. Aquinas is often thought
of as someone with a precise or definite concept of God, someone who
thinks he can explain just what God is. But in a passage immediately
following the text of the Five Ways, he writes,
Having recognized that a certain thing exists, we have still to
investigate the way in which it exists, that we may come to
understand what it is that exists. Now we cannot know what
God is, but only what he is not; we must therefore consider
the ways in which God does not exist, rather than the ways
in which he does.
(ibid.)
The same move is made in the Summa Contra Gentiles. Book I, Chapter
13 of the treatise is called ‘Arguments in proof of the existence of God’.
Chapter 14 begins with the assertion, ‘The divine substance surpasses
every form that our intellect reaches. Thus we are unable to apprehend
it by knowing what it is.’
In saying that God and his attributes are identical, Aquinas is not
saying that, for example, ‘God is good’ means the same as ‘God exists’.
And he is certainly not saying that God is a property.35 He means that
certain things that are true of creatures are not true of God. More
precisely, he means that God is nothing material. On Aquinas’s account,
material things possessing a nature cannot be identified with the nature
they possess. Thus, for example, Socrates is not identical with human
nature. But what is it that allows us to distinguish between Socrates
and other human beings? Aquinas says that Socrates is different from
other human beings not because of his nature but because of his matter.
Socrates is different from me because he was one parcel of matter and
I am another. It is materiality which allows Socrates to be a human
being rather than human nature. And, since Aquinas denies that God
is something material, he therefore concludes that God and his nature
are not distinguishable. He also reasons that angels and their natures
are not distinguishable. The angel Gabriel is not a material object.
And neither is the angel Michael. So, says Aquinas, Gabriel is his nature,
and Michael is his nature. Or, as we may put it, God, Gabriel and
Michael are not individual members of a species or genus.36
With respect to the question of knowing what God is, we need to be
warned that Aquinas does not deny that we can know ourselves to
speak truly when we make certain statements about God.37 Aquinas
spends a great deal of time arguing that many propositions concerning
God can be proved to be true in philosophical terms. But he denies
that we can understand the nature of God. On his account, our
knowledge of what things are depends on our ability to experience
them by means of our senses and to classify them accordingly. Since he
holds that God is nothing material, he therefore denies that God is
known by the senses and classifiable on the basis of sensory experience.
The knowledge that is natural to us has its source in the
senses and extends just so far as it can be led by sensible
things; from these, however, our understanding cannot reach
to the divine essence… In the present life our intellect has a
natural relation to the natures of material things; thus it
understands nothing except by turning to sense images… In
this sense it is obvious that we cannot, primarily and
essentially, in the mode of knowing that we experience,
understand immaterial substances since they are not subject
to the senses and imagination… What is understood first by
us in the present life is the whatness of material
things…[hence]… we arrive at a knowledge of God by way
of creatures.
(Summa theologiae, Ia, 12, 12; 88, 1; 88, 3)
On Aquinas’s account, our knowledge of God is derived from what
we know of things in the world and from what we can sensibly deny
or affirm of God given that he is not something in the world. So, says
Aquinas, God is not a physical object which can be individuated as a
member of a class of things which can be distinguished from each other
with reference to genus and species. Among other things, Aquinas also
argues that God is unchangeable and non-temporal (since he is the
first cause of change, and since time is real since changes occur).38
In distinguishing God from creatures, however, Aquinas lays the
greatest stress on the teaching that God is uncreated. One way in which
he does so is to say that there is no ‘potentiality’ in God. To understand
his teaching on God it will help if we try to understand what he means
by saying this.
We can start by noting what Aquinas means by ‘potentiality’. And
we can do so by thinking of my cat Fergus. He is a lovely and loving
creature, and I am deeply fond of him. But he is no Platonic form.
Plato thought of the forms as unchangeable. But Fergus is changing all
the time. He gets fat as I feed him. And he is constantly changing his
position. So he is a serious threat to the local mice.
Aquinas would say that when Fergus weighs nine pounds he is also
potentially eight and ten pounds in weight. Fergus might weigh nine
pounds, but he could slim to eight pounds or grow to ten pounds.
Aquinas would also say that when Fergus is in the kitchen, he is
potentially in the living room. For Fergus has a habit of moving around.
What if Fergus ends up strolling on to a busy road? He stands a
strong chance of becoming a defunct cat. Or, as Aquinas would say,
Fergus is actually a cat and potentially a corpse. Fergus is vulnerable to
the activity of things in the world. And some of them can bring it
about that he ceases to be the thing that he is.
We can put this by saying that Fergus is potentially non-existent as
a cat. And that is what Aquinas would say. But he would add that
there is a sense in which Fergus is potentially non-existent quite apart
from the threat of a busy road and the like. For there might be no
Fergus at all, not just in the sense that there might never have been cats
who acted so that Fergus was born, but in the sense that Fergus might
not continue to exist. According to Aquinas, anything created is
potential since its existence depends on God (since anything created is
potentially non-existent). In his view, we are entitled to ask why
anything we come across is there. And, so he thinks, in asking this
question we need not be concerned with temporally prior causes or
identifiable causes in the world which sustain things in the state in
which they are. We can be asking about the fact that there is anything
there to be produced or to be sustained. What accounts for the fact
that such things exist at all? What accounts for there being a world in
which we can ask what accounts for what within it?
Aquinas holds that, if we take these questions seriously, we must
believe in the existence of something which is wholly lacking in
potentiality, i.e. God. Fergus can change physically and he has
potentiality accordingly. But God is no physical thing, and, since he
accounts for there being a world, he cannot be potentially non-existent.
He does not ‘have’ existence. His existence is not received or derived
from another. He is his own existence (ipsum esse subsistens) and the
reason why other things have it.
Properties that belong to a thing over and above its own
nature must derive from somewhere, either from that nature
itself…or from an external cause… If therefore the existence
of a thing is to be other than its nature, that existence must
either derive from the nature or have an external cause. Now
it cannot derive merely from the nature, for nothing with
derived existence suffices to bring itself into being. It follows
then that, if a thing’s existence differs from its nature, that
existence must be externally caused. But we cannot say this
about God, whom we have seen to be the first cause. Neither
then can we say that God’s existence is other than his nature.
(Summa theologiae, Ia, 3, 4)
In Aquinas’s view, this would be true even if the created order contained
things which are not material. For suppose there were immaterial beings
other than God, as Aquinas took angels to be.39 They would differ
from material things since they would have no in-built tendency to
perish or move around. In the language of Aquinas, they would be
‘necessary’ beings rather than ‘contingent’ ones. They would also be
identical with their natures, for, as we have seen, Aquinas held that
there are no two angels of the same kind or ‘species’. But they would
still be potentially non-existent since they would receive their existence
from God. And, though they could not decay or perish at the hands of
other creatures, it would be possible for God to de-create (annihilate)
them. They would not therefore exist simply by being what they are.
‘Without doubt’, says Aquinas, ‘the angels, and all that is other than
God, were made by God. For only God is his existence; in all else
essence and existence are distinct.’40 Or, as he also explains,
Some things are of a nature that cannot exist except as
instantiated in individual matter—all bodies are of this kind.
This is one way of being. There are other things whose
natures are instantiated by themselves and not by being in
matter. These have existence simply by being the natures they
are: yet existence is still something they have, it is not what
they are—the incorporeal beings we call angels are of this
kind. Finally there is the way of being that belongs to God
alone, for his existence is what he is.
(Summa theologiae, Ia, 12, 4)
GOD AND HIS CREATION
How does Aquinas think of God as relating to his creation? In writing
about the relation between God and creatures, one of the things he
says is that God is not really related to creatures, though creatures are
really related to God. In his own words:
Since God is altogether outside the order of creatures, since
they are ordered to him but not he to them, it is clear that
being related to God is a reality in creatures, but being
related to creatures is not a reality in God.41
But what does he mean in saying this? And how does what he says
connect with his belief that God is the creator and sustainer of everything
other than himself?
One might suppose that the words of Aquinas just quoted constitute
a flagrant violation of obvious truths. If A is related to B, then B must
be related to A. What could be more obvious than that? But Aquinas’s
teaching on God and his relation to creatures is not a denial of the
principle ‘If aRb, then bRa’. If one reads him on the question of God’s
relation to creatures, one will find him endorsing all of the following
propositions.
1 We can speak of God as related to his creatures in view of the purely
formal point that if one thing can be said to be related to another,
then the second thing can be said to be related to the first.
2 Since God can be compared to creatures, since he can be spoken of
as being like them, he can be thought of as related to them.
3 Since God knows creatures, he can be said to be related to them.
4 Since God moves creatures, he can be said to be related to them.
5 Since God can be spoken of as ‘first’, ‘highest’ and so on, he can be
said to be related to creatures since these terms are relational ones.42
In saying that ‘being related to creatures is not a reality in God’, Aquinas’s
primary concern is to deny that God is changed because he has created.
Aquinas denies that God is something which has to create. In his view,
God creates freely, and to understand what God is essentially would not
be to see that he is Creator of the world. God, indeed, has created the
world. But, says Aquinas, he does not produce the world as kidneys produce
urine. For him, God is able to create, but he is not essentially a creator (as
kidneys are essentially producers of urine).43 So Aquinas reasons that the
essence of God is in no way affected by the existence of created things and
that being the Creator of creatures is not something in God. God does not
become different by becoming the Creator of things. Nor does he change
because his creatures change. For Aquinas, the fact that there are creatures
makes no difference to God, just as the fact that my coming to know that
Fred is bald makes no difference to Fred (my coming to know that Fred is
bald does not change him, even though he might be deeply affected by
learning that I have come to know of his baldness). In Aquinas’s view,
God is unchangeably himself. And he remains so even though it is true
that there are things created and sustained by him.
This aspect of Aquinas’s teaching allows him to take a view of God’s
activity which is quite at odds with that to be found in the work of
many philosophers and theologians both ancient and modern. It has
often been said that the action of God is a process undergone by God
with effects in the world of created things. When I act, I do something
in addition to what I have been previously doing. I go through a series
of successive states. And my going through these states sometimes leads
to changes in things apart from myself. By the same token, so it has
often been argued, God acts by being a subject under-going successive
states some of which have effects in things other than him. But this is
not Aquinas’s position. On his account, the action of God is not a
process undergone by him. It is a process undergone in things other
than God. For Aquinas, God’s action is the history of created things.
One of the things which Aquinas takes this to mean is that God
cannot, strictly speaking, be thought of as intervening in the world.
According to the usual sense of ‘intervene’, to say that X has intervened
is to say that X has come to be present in some situation from which X
was previously absent. Thus, for example, to say that I intervened in a
brawl is to say that I moved into a fight of which I was not originally
a part. But Aquinas holds that God can never be absent from anything.
On his account, God is everywhere as making all places.44 He also says
that God is in all things as making them to be. Hence, for example, he
refuses to think of miracles as cases of divine intervention. It is often
said that to believe in miracles is to believe in a God who can intervene.
The idea seems to be that a God capable of performing miracles must
be one who observes a given scenario and then steps in to tinker with
it. But God, for Aquinas, can never intervene in his creation in this
sense. He therefore maintains that God is as present in what is not
miraculous as he is in the miraculous. Miracles, for him, do not occur
because of an extra added wonder ingredient (i.e. God). They occur
because something is not present (i.e. a cause other than God, or a
collection of such causes).45
This thought of Aquinas should be connected with another of his
prevailing theses: that free human actions are caused by God. He
frequently alludes to arguments suggesting that people cannot be free
under God’s providence. In On Evil VI, for instance, we find the three
following arguments, from the twenty-four in all, against the thesis
that human beings have a free choice of their actions:
If change is initiated in the human will in a fixed way by
God, it follows that human beings do not have free choice of
their actions. Moreover, an action is forced when its
originating principle is outside the subject, and the victim of
force does not contribute anything to it. So if the originating
principle of a choice which is made voluntarily is outside the
subject—in God—then it seems that the will is changed by
force and of necessity. So we do not have free choice of our
actions. Moreover, it is impossible that a human will should
not be in accordance with God’s will: as Augustine says in
the Enchiridion, either a human being does what God wills
or God fulfils his will in that person. But God’s will is
changeless; so the human will is too. So all human choices
spring from a fixed choice.
A similar kind of argument constitutes the third objection to Ia, 83, 1:
What is free is cause of itself, as the Philosopher says
(Metaphysics 1.2). Therefore what is moved by another is
not free. But God moves the will, for it is written (Prov.
21:1): The heart of the king is in the hand of the Lord;
whithersoever He will He shall turn it; and (Phil. 2:13): It is
God Who worketh in you both to will and to accomplish.
Therefore people do not have free-will.
Yet Aquinas insists that the reality of providence (which means the
reality of God working in all things as first cause and sustainer) is not
incompatible with human freedom.
To begin with, he says, people certainly have freedom. For one thing,
the Bible holds that they do (in Ia, 83, 1 Aquinas cites Ecclesiasticus
15:14 to this effect). For another, people, as rational agents, have it in
them to choose between alternative courses of action (unlike inanimate
objects or animals acting by instinct).46 They also have it in them to act
or refrain from acting. In fact, says Aquinas, human freedom is a
prerequisite of moral thinking.
If there is nothing free in us, but the change which we desire
comes about of necessity, then we lose deliberation,
exhortation, command and punishment, and praise and
blame, which are what moral philosophy is based on.
(On Power, VI; Summa theologiae, Ia, 83, 1)
Secondly, so Aquinas continues, human actions falling under providence
can be free precisely because of what providence involves. In his view
we are not free in spite of God, but because of God.
God does indeed change the will, however, in an unchanging
manner, because of the manner of acting of God’s changeinitiating
power, which cannot fail. But because of the nature
of the will which is changed—which is such that it is related
indifferently to different things—this does not lead to
necessity, but leaves freedom untouched. In the same way
divine providence works unfailingly in everything, but
nevertheless effects come from contingent causes in a
contingent manner, since God changes everything in a
relative way, relative to the manner of existence of each
thing… The will does contribute something when change is
initiated in it by God: it is the will itself that acts, though the
change is initiated by God. So though its change does come
from outside as far as the first originating principle is
concerned, it is nevertheless not a forced change.
(On Evil, VI)
In other words, human freedom is compatible with providence because
only by virtue of providence is there any human freedom. God, for
Aquinas, really does act in everything. And since ‘everything’ includes
human free actions, Aquinas concludes that God works in them as
much as in anything else.
People are in charge of their acts, including those of willing and
of not willing, because of the deliberative activity of reason,
which can be turned to one side or the other. But that someone
should deliberate or not deliberate, supposing that one were in
charge of this too, would have to come about by a preceding
deliberation. And since this may not proceed to infinity, one
would finally have to reach the point at which a person’s free
decision is moved by some external principle superior to the
human mind, namely by God, as Aristotle himself
demonstrated. Thus the minds even of healthy people are not so
much in charge of their acts as not to need to be moved by God.
(Summa theologiae, Ia2ae, 109, 3, ad. 1)
The same idea is expressed in Aquinas’s commentary on Aristotle’s
On Interpretation:
If divine providence is, in its own right, the cause of
everything that happens, or at least of everything good, it
seems that everything happens of necessity… God’s will
cannot be thwarted: so it seems that whatever he wants to
happen happens of necessity… [But] we have to notice a
difference as regards the divine will. The divine will should
be thought of as being outside the ordering of existent
things. It is the cause which grounds every existent, and all
the differences there are between them. One of the
differences between existents is between those that are
possible and those that are necessary. Hence necessity and
contingency in things have their origin in the divine will, as
does the distinction between them, which follows from a
description of their proximate causes. God lays down
necessary causes for the effects that he wants to be necessary,
and he lays down causes that act contingently—i.e. that can
fail of their effect—for the effects that he wants to be
contingent. It is according to this characteristic of their
causes that effects are said to be necessary or contingent,
even though they all depend on the divine will, which
transcends the ordering of necessity and contingency, as their
first cause… The will of God cannot fail: but in spite of that,
not all its effects are necessary; some are contingent.
(On ‘On Interpretation’, Bk I, lectio 14)
By ‘necessary’ here Aquinas means ‘determined’ or ‘brought about by
causes necessitating their effects’. By ‘contingent’ he means ‘undetermined’
or ‘able to be or not to be’. His suggestion, therefore, is that God wills
both what is determined and what is undetermined. Since he believes
that each must derive from God’s will, he locates them within the context
of providence. But since he also believes that the determined and
undetermined are genuinely different, he concludes that providence can
effect what is undetermined as well as what is determined. And, on this
basis, he holds that it can effect human free actions.
One may, of course, say that if my actions are ultimately caused by
God then I do not act freely at all. But Aquinas would reply that my
actions are free if nothing in the world is acting on me so as to make
me perform them, not if God is not acting in me. According to him,
what is incompatible with human free will is ‘necessity of coercion’ or
the effect of violence, as when something acts on one and ‘applies force
to the point where one cannot act otherwise’.47 As Herbert McCabe
explains, Aquinas’s position is that ‘to be free means not to be under
the influence of some other creature, it is to be independent of other
bits of the universe; it is not and could not mean to e independent of
God’.48 For Aquinas, God does not interfere with created free agents
to push them into action in a way that infringes their freedom. He
does not act on them (as Aquinas thinks created things do when they
cause others to act as determined by them). He makes them to be what
they are, namely freely acting agents. In Aquinas’s words,
Free-will is the cause of its own movement, because by their
free-will people move themselves to act. But it does not of
necessity belong to liberty that what is free should be the first
cause of itself, as neither for one thing to be the cause of
another need it be the first cause. God, therefore, is the first
cause, who moves causes both natural and voluntary. And
just as by moving natural causes he does not prevent their
acts being natural, so by moving voluntary causes he does
not deprive their actions of being voluntary: but rather is he
the cause of this very thing in them; for he operates in each
thing according to its own nature.
(Summa theologiae, Ia, 83, 1, ad. 3)
HUMAN BEINGS
On this account, people are totally dependent on God for all that they
are. But the account is a very theological one. And one might wonder
how Aquinas thinks of people without also thinking about God. What,
for example, would he write if asked to contribute to a modern
philosophical book on the nature of human beings?49
The first thing he would say is that human beings are animals. So
they are, for example, capable of physical movement. And they have
biological characteristics. They have the capacity to grow and
reproduce. They have the need and capacity to eat. These characteristics
are not, for Aquinas, optional extras which people can take up and
discard while remaining people. They are essential elements in the makeup
of any human being. And they are very much bound up with what
is physical or material.
This line of thinking, of course, immediately sets Aquinas apart from
writers who embrace a ‘dualistic’ understanding of human beings—
writers like Descartes, for instance.50 For Aquinas, my body is not
distinct from me because it is a different substance or thing from me.
On his account, if a human being is there, then so is a human body.
For as it belongs to the very conception of ‘this human being’
that there should be this soul, flesh and bone, so it belongs to
the very conception of ‘human being’ that there be soul, flesh
and bone. For the substance of a species has to contain
whatever belongs in general to every one of the individuals
comprising that species.
(Summa theologiae, Ia, 75, 4)
Aquinas often refers to the thesis that people are essentially substances
different from bodies on which they act (a view which he ascribes to
Plato). But he emphatically rejects this thesis.
Plato and his followers asserted that the intellectual soul is not
united to the body as form to matter, but only as mover to
movable, for Plato said that the soul is in the body ‘as a sailor
in a ship’. Thus the union of soul and body would only be by
contact of power… But this doctrine seems not to fit the facts.
(Summa contra Gentiles, II, 57)
If our souls moved our bodies as sailors move ships, says Aquinas, my
soul and my body would not be a unity. He adds that if we are souls
using bodies, then we are essentially immaterial, which is not the case.
We are ‘sensible and natural realities’ and cannot, therefore, be
essentially immaterial.51
But this is not to say that Aquinas thinks of people as irreducibly
material. He is not, in the modern sense, a philosophical ‘physicalist’.52
We have just seen that he is prepared to speak about people as having
souls. And, on his account, a proper account of the human soul (anima)
will deny that it is wholly material. By ‘soul’, Aquinas means something
like ‘principle of life’. ‘Inquiry into the nature of the soul’, he writes,
‘presupposes an understanding of the soul as the root principle of life
in living things within our experience’.53 And, in Aquinas’s thinking,
the root principle of life in human beings (the human soul) is nonmaterial.
It is also something ‘subsisting’.
In arguing for the non-corporeal nature of the human soul, Aquinas
begins by reminding us what anima means, i.e. ‘that which makes living
things live’. And, with that understanding in mind, he contends that
soul cannot be something bodily. There must, he says, be some principle
of life which distinguishes living things from non-living things, and
this cannot be a body. Why not? Because if it were a body it would
follow that any material thing would be living, which is not the case. A
body is alive not just because it is a body. It is alive because of a principle
of life which is not a body.
It is obvious that not every principle of vital activity is a soul.
Otherwise the eye would be a soul, since it is a principle of
sight; and so with the other organs of the soul. What we call
the soul is the root principle of life. Now though something
corporeal can be some sort of principle of life, as the heart is
for animals, nevertheless a body cannot be the root principle
of life. For it is obvious that to be the principle of life, or that
which is alive, does not belong to any bodily thing from the
mere fact of its being a body; otherwise every bodily thing
would be alive or a life-source. Consequently any particular
body that is alive, or even indeed a source of life, is so from
being a body of such-and-such a kind. Now whatever is
actually such, as distinct from not-such, has this from some
principle which we call its actuating principle. Therefore a
soul, as the primary principle of life, is not a body but that
which actuates a body.
(Summa theologiae, Ia, 75, 1)
In other words, if bodily things are alive just because they are bodies,
all bodily things (e.g. my alarm clock) would be alive, which they are
not. So what makes something a living thing cannot be a body.
But why say that the human soul is something subsisting? The main
point made by Aquinas in anticipating this question is that the human
animal has powers or functions which are not simply bodily, even
though they depend on bodily ones. For example, people can know
and understand, which is not the case with that which is wholly material.
As Aquinas puts it, people enjoy an intellectual life and they are things
of the kind they are (rational animals) because of this. Aquinas calls
that by virtue of which people are things of the kind they are their
‘souls’. So he can say that human beings are bodily, but also that they
are or have both body and soul. The two cannot be torn apart in any
way that would leave what remained a human being. But they can be
distinguished from each other and the soul of a human being can
therefore be thought of as something subsisting immaterially.
The principle of the act of understanding, which is called the
human soul, must of necessity be some kind of incorporeal
and subsistent principle. For it is obvious that the
understanding of people enables them to know the natures of
all bodily things. But what can in this way take in things must
have nothing of their nature in its own, for the form that was
in it by nature would obstruct knowledge of anything else. For
example, we observe how the tongue of someone sick with
fever and bitter infection cannot perceive anything sweet, for
everything tastes sour. Accordingly, if the intellectual principle
had in it the physical nature of any bodily thing, it would be
unable to know all bodies. Each of them has its own
determinate nature. Impossible, therefore, that the principle of
understanding be something bodily. And in the same way it is
impossible for it to understand through and in a bodily organ,
for the determinate nature of that bodily organ would prevent
knowledge of all bodies. Thus if you had a colour filter over
the eye, and had a glass vessel of the same colour, it would not
matter what you poured into the glass, it would always appear
the same colour. The principle of understanding, therefore,
which is called mind or intellect, has its own activity in which
body takes no intrinsic part. But nothing can act of itself
unless it subsists in its own right. For only what actually exists
acts, and its manner of acting follows its manner of being. So
it is that we do not say that heat heats, but that something hot
heats. Consequently the human soul, which is called an
intellect or mind, is something incorporeal and subsisting.
(Summa theologiae, Ia, 75, 2)
Aquinas’s notion that the human soul ‘subsists’ does not entail that it
is a complete and self-contained entity, as, for example, Descartes
thought the soul to be. For Aquinas, my human soul subsists because
I have an intellectual life which cannot be reduced to what is simply
bodily. It does not subsist as something with its own life apart from
me, any more than my left hand does, or my right eye. Both of these
can be spoken of as things, but they are really parts of me. We do not
say, ‘My left hand feels’ or ‘My right eye sees’; rather we say, ‘I feel
with my left hand’ and ‘I see with my right eye’. And Aquinas thinks
that something similar should be said about my soul. I have a human
soul because I have intellect and will. But it is not my soul which
understands and wills. I do.
One might put this by saying that my soul is not I. And Aquinas
says exactly this in his Commentary of St Paul’s first letter to the
Corinthians.54 In that case, however, what happens to me when I die?
Aquinas maintains that people are essentially corporeal. This means
that I am essentially corporeal. For I am a human being. So am I to
conclude from what Aquinas holds that I cease to exist at death? Can
I look forward to nothing in the way of an afterlife?
Aquinas has a number of answers to these questions. Since he thinks
of people as essentially corporeal, he agrees that there is a sense in
which they cease to exist at death. But, since he believes that God can
raise the dead to bodily life, he denies that the fact that I die entails
that I cease to exist. On the other hand, he does not believe that most
of those who have died have been raised to bodily life. He is certain
that Christ has been raised to bodily life. But he would deny that the
same can be truly asserted of, for example, Julius Caesar. He would
therefore say that the soul of Caesar survives, though Caesar himself
does not.
Given what we have now seen of Aquinas’s teaching, it should be
evident why he would deny that now, when he has not been raised to
bodily life, Caesar survives his death. But why should Aquinas think
that Caesar’s soul would survive his death? Does he subscribe to the
view that the human soul is immortal? Does he maintain that, though
Caesar might die, his soul must survive the death of his body?
The answer to the last two questions is ‘Yes’. Aquinas does believe
that human souls are immortal. He also believes that they must survive
the death of human beings. That by virtue of which I understand and
think, he reasons, is not the sort of thing which can die as bodies can
die.55 He is well aware that people die and that their bodies perish. As
we have seen, however, people, for Aquinas, are rational, understanding
animals who are what they are by virtue of what is not material. He
therefore concludes that there must be something about them capable
of surviving the destruction of what is material. He does not think we
can prove that the soul of Caesar must survive his death. In Aquinas’s
view, whether or not Caesar’s soul survives the death of Caesar depends
on whether God wills to keep it in being. And Aquinas does not think
that we are in any position to prove that God must do that. For him,
therefore, there is no ‘proof of the immortality of the soul’. He holds
that Caesar’s soul could cease to exist at any time. But he also thinks
that it is not the sort of thing of which it makes sense to say that it can
perish as bodies can perish.
On the other hand, however, he does not think of it as the sort of
thing which can survive as a human animal can survive. So the survival
of Caesar’s soul is not the survival of the human being we call ‘Julius
Caesar’. People, for Aquinas, are very much part of the physical world.
Take that world away and what you are left with is not a human person.
You are not, for example, left with something able to know by means
of sense experience.56 Nor are you left with something able to undergo
the feelings or sensations that go with being bodily. On Aquinas’s
account, therefore, a human soul can only be said to survive its body
as something purely intellectual, as the locus of thought and will.
Understanding through imagery is the proper operation of
the soul so far as it has the body united to it. Once separated
from the body it will have another mode of understanding,
like that of other disembodied natures… It is said, people are
constituted of two substantial elements, the soul with its
reasoning power, the flesh with its senses. Therefore when
the flesh dies the sense powers do not remain… Certain
powers, namely understanding and will, are related to the
soul taken on its own as their subject of inhesion, and
powers of this kind have to remain in the soul after the death
of the body. But some powers have the body-soul compound
for subject; this is the case with all the powers of sensation
and nutrition. Now when the subject goes the accident
cannot stay. Hence when the compound corrupts such
powers do not remain in actual existence. They survive in the
soul in a virtual state only, as in their source or root. And so
it is wrong to say, as some do, that these powers remain in
the soul after the dissolution of the body. And it is much
more wrong to say that the acts of these powers continue in
the disembodied soul, because such powers have no activity
except through a bodily organ.
(Summa theologiae, Ia, 75, 6 ad. 3 and Ia, 77, 8)
Peter Geach observes that Aquinas’s description of the life that would
be possible for disembodied souls is ‘meagre and unattractive’.57 And
many will agree. But the description now in question is all that Aquinas
feels able to offer as a philosopher. As a Christian theologian he feels
able to say that the dead will be raised to a newness of life of a highly
attractive kind. His final position is that, following the Incarnation of
God in Christ, people can be raised in their bodies to share in God’s
life.58 But the truth of this position, on Aquinas’s own admission, is in
no way demonstrable by means of philosophical argument. It follows
from the teachings of Christ. On Aquinas’s account, we are warranted
in believing what Christ taught. For Christ was divine. Yet, so Aquinas
adds, though we can give some rational grounds for believing in the
divinity of Christ, we cannot prove that Christ was God.59 Belief in the
divinity of Christ is a matter of faith. It is not a matter of knowledge.
Though it is not unreasonable, it is not demonstrably true. If we
subscribe to it, that can only be because God has given us the theological
virtue of faith.60
FAITH AND PHILOSOPHY
Aquinas’s writings on faith provide good examples of texts which
should lead us to challenge a view of medieval philosophy which has
been referred to as ‘separationism’.61 Some students of Aquinas try
rigidly to separate his theology from his philosophy. They then go on
to write about him on the assumption that some of his texts are
‘theological’ while others are ‘philosophical’. But Aquinas himself made
no such sharp distinction between theology and philosophy. And even
what he says of faith shows him to be weaving together what later
authors separate under the headings ‘theology’ and ‘philosophy’. The
object of faith is God, he says.62 Some will call this a statement of
theology. The virtue of faith, he continues, involves holding fast to
truths which philosophy cannot demonstrate.63 That, too, might be
called a theological conclusion. But in calling God the object of faith
Aquinas draws on views about truth, falsity, belief and propositions
which, in his opinion, ought to seem rationally acceptable to anyone.
And in arguing that philosophy cannot demonstrate the truths of faith
he defends himself with reference to what he thinks about human
knowledge in general (apart from revelation) and what he thinks we
must conclude given what our reason can tell us of God. So his teaching
on faith can also be viewed as philosophical.
These facts bring us back again to the question touched on earlier. Is
Aquinas really a philosopher? From what we have now seen of his
thinking, it should be clear why the question cannot be answered if an
answer must presume on our being able to draw a clear and obvious
distinction between the philosophy of Aquinas and the theology of
Aquinas. In his writings, philosophical arguments and theses are used
to reach conclusions of theological import. And theses of theological
import lead to judgements which can readily be called philosophical.
And the result can be studied as something containing matters of interest
to thinkers with any religious belief or none. In this chapter I have
tried to give some indication of what these matters are. A complete
account of Aquinas’s thinking would have to report more than space
here allows me. Those who read Aquinas for themselves, however, will
quickly get a sense of what that might involve.
NOTES
1 For discussion of the date of Aquinas’s birth see Tugwell [11.8], 291ff.
2 For the Irish influence on Aquinas see Michael Bertram Crowe, ‘Peter of Ireland:
Aquinas’s teacher of the ARTES LIBERALES’, in Arts Liberaux et Philosophie
au Moyen Age, Paris, 1969.
3 As well as being influenced by Aristotle, Aquinas was also indebted to elements in the
thought of Plato and to later writers of a ‘Platonic’ caste of mind. He commented on
the Book about Causes (Liber de causis), an excerpted and adapted version of the
Elements of Theology by the late Neoplatonist Proclus (c. 410–85). He also commented
on Dionysu the Areopagite. And ‘Platonic’ theories and styles of argument abound in
his writings.
4 Readers interested in understanding the origins and spirit of the Dominicans are
best advised to consult Simon Tugwell OP (ed.) Early Dominicans, New York,
Ramsey and Toronto, 1982.
5 Bertrand Russell, A History of Western Philosophy, London, 1946, pp. 484ff.
6 For an exposition of Gilson on this matter see John F.Wippel, ‘Etienne Gilson
and Christian philosophy’, in [11.40].
7 St Thomas Aquinas: Faith, Reason and Theology: Questions I–IV of his
Commentary on the De Trinitate of Boethius, translated with introduction and
notes by Armand Maurer, Toronto, 1987, p. xv. Pegis elaborates his position in
‘Sub ratione Dei: a reply to Professor Anderson’, The New Scholasticism 39 (1965).
Pegis is here responding to James Anderson’s ‘Was St Thomas a Philosopher?’, The
New Scholasticism 38 (1964). Anderson asked whether Aquinas was a philosopher
and replied that he was.
8 Cf. Leonard E.Boyle, The Setting of the Summa Theologiae of Saint Thomas
(Etienne Gilson Series 5), Toronto, 1982, pp. 17 and 30.
9 On the basis of a fourteenth-century life of St Raymund of Peñafort (c. 1178–
1280), tradition holds that the Summa contra Gentiles was commissioned as an
aid for Dominican missionaries preaching against Muslims, Jews and heretical
Christians in Spain and North Africa. This theory has been subject to recent
criticism, but it has also been recently defended. Cf. Summa contra Gentiles, I,
text and French translation, with an Introduction by A.Gauthier, Paris, 1961,
and A.Patfoort, Thomas d’Aquin: les Clés d’une Théologie, Paris, 1983.
10 Introduction to Summa theologiae, Ia, 2.
11 Summa theologiae, Ia, 44, 1.
12 Summa theologiae, Ia, 44, 4
13 Summa theologiae, Ia, 6, 1.
14 Cf. Summa theologiae, Ia, 12, 5; Ia2ae, 62, 1; Ia2ae, 110, 1; Ia2ae, 112, 1.
15 Cf. Summa theologiae, 2a2ae, 2, 4.
16 For Aristotle, see Posterior Analytics, I, 10. For Aquinas, see Summa theologiae,
Ia, 2, 1; On Truth, I, 12; XV, 1. I am using ‘believe’ here in the loose sense of ‘take
to be true or accept’. Aquinas himself would not speak of believing first principles
of demonstration. These, for him, are known or understood.
17 Cf. Summa theologiae, Ia, 1, 1; 2a2ae, 2, 3. See also Aquinas’s inaugural lecture
(principium) as Master in Theology at Paris (1256). This text can be found in the
Marietti edition of Aquinas’s Opuscula theologica, Turin, 1954, and is translated
in Tugwell [11.8], 355ff.
18 For Anselm, see Proslogion, II and III. For Aquinas, see Summa theologiae, Ia, 2, 1;
Summa contra Gentiles, I, 11. The argument discussed in the passages from Aquinas
just cited was not so much Anselm’s as a version of Anselm’s argument current in
the thirteenth century and offered by writers such as Alexander of Hales (c. 1186–
1245). For a discussion of the matter, see Jean Chatillon, ‘De Guillaume d’Auxerre
à saint Thomas d’Aquin: l’argument de saint Anselme chez les premiers scholastiques
du XIIIe siècle’, in Jean Chatillon, D’Isidore de Séville à saint Thomas d’Aquin,
London, 1985.
19 Cf. On Truth, X, 4–6; Summa theologiae, Ia, 84–8. For reasons of space I am not
here going into details on Aquinas’s teaching on the source of human knowledge.
For an introductory account see Marenbon [Intr. 10], 11631 and 134–5.
20 Cf. Summa contra Gentiles, I, 14; Summa theologiae, Ia, 12, 4 and 11.
21 Cf. Summa theologiae, Ia, 12, 1.
22 See William Lane Craig, The Cosmological Argument from Plato to Leibniz,
London, 1980, ch. 5; Elders [11.16], ch. 3; van Steenberghen [11.36], 165ff.
23 One might reasonably deny that God is an ‘explanation’ of anything for Aquinas.
One might say that an explanation of such and such is something we understand
better than the thing with respect to which we invoke it as an explanation. Aquinas
would agree with this observation. But if ‘explanation’ means ‘cause’, he would
insist that God is an ‘explanation’ of what we find around us.
24 Aristotle presents an argument like that of Aquinas in Physics VII. Aquinas
acknowledges his debt to Aristotle’s argument in Summa contra Gentiles, I, 13
where he offers a longer version of what appears in the Summa theologiae as the
First Way.
25 Aquinas here is concerned with what he calls motus. For him this includes change
of quality, quantity or place (hence the legitimacy of translating motus as ‘change’
or ‘movement’).
26 Aquinas calls the First Way ‘the most obvious’ (manifestior) proof. That, I presume,
is chiefly because what he calls motus is something which impinges on us all the
time. Maimonides and Averroes are two other authors who thought that the
truth of the reasoning which surfaces in the First Way is particularly evident. Cf.
Maimonides (see [4.13], I, 70) and Averroes (see [3.17] IV).
27 Aquinas does not mean that the world does not contain things which can be thought
of as changing themselves, e.g. people. He means that nothing in the world is wholly
the source of its change. Cf. Christopher Martin [11.22] 61.
28 For Aquinas on time and change see Summa theologiae, Ia, 10, 1 and Lectures
15–20 of Aquinas’s commentary on Aristotle’s Physics. That the First Way is an
argument from the reality of time is suggested by David Braine, The Reality of
Time and the Existence of God, Oxford, 1988.
29 Some of the key concepts in the Third Way are found in Aristotle. Maimonides
offers an argument very similar to that of the Third Way in The Guide of the
Perplexed II, 1. One can also compare the Third Way with a proof of God’s
existence given by Avicenna (cf. Arthur J.Arberry, Avicenna on Theology, London,
1951, p. 25 for the text in English). But Aquinas’s Third Way is a distinct argument
and not just a straightforward repetition of earlier arguments with which it may
be compared.
30 Cf. Patterson Brown, ‘St Thomas’ doctrine of necessary being’, in Kenny [11.27].
31 There is a textual problem concerning the Third Way which my brief account of
it bypasses. For a discussion of the issues and for a treatment of different
interpretations of the Third Way see van Steenberghen [11.36] 188–201, and
Craig, Cosmological Argument, pp. 182–94.
32 In the Fourth Way the background to the argument seems chiefly Platonic. Aquinas
holds that perfection admits of degrees, a notion found in Plato, St Augustine, St
Anselm and many others. The Platonic theory which seems to lie behind the Fourth
Way is expounded with reference to the Way in Kenny [11.28] ch. 5.
33 Here Aquinas invokes the notion of final causality or teleological explanation,
which can be found in Book II of Aristotle’s Physics. For Aristotle, a final cause
or a teleological explanation was an answer to the question ‘To what end or
purpose is this happening?’ For an exposition and discussion of Aristotle on
purpose in nature, see Richard Sorabji, Necessity, Cause and Blame: Perspectives
on Aristotle’s Theory, London, 1980, chs 10 and 11. The argument of the Fifth
Way is given in more detail by Aquinas in On Truth, V, 2.
34 For a more detailed account of this proposal see Brian Davies, ‘Classical theism
and the doctrine of divine simplicity’, in Brian Davies (ed.) Language, Meaning
and God, London, 1987.
35 In Does God have a Nature?, Milwaukee, 1980, Alvin Plantinga erroneously
attributes to Aquinas the suggestion that God is a property.
36 Summa theologiae, Ia, 50, 4.
37 P.T.Geach properly draws attention to this point in Three Philosophers, Oxford,
1973, p. 117.
38 Cf. note 27 above.
39 Cf. Summa theologiae, Ia, 50, 2.
40 Summa theologiae, Ia, 61, 2.
41 Summa theologiae, Ia, 13, 7. Cf. also Summa contra Gentiles, II, 11 and On
Power, VII, 8–11. For modern philosophical discussion of the suggestion, see
Peter Geach, ‘God’s relation to the world’, Sophia 8, 2 (1969):1–9 and C.J.
F.Williams, ‘Is God really related to his creatures?’, Sophia 8, 3 (1969):1–10.
42 On Power, VII, 10.
43 Cf. Summa theologiae, Ia, 19, 1, 3, 10.
44 Summa theologiae, Ia, 8, 2.
45 Aquinas therefore holds that only God can produce miracles (Summa theologiae, Ia,
110, 4). Aquinas treats of miracles at some length in Summa theologiae, Ia, 105, Summa
contra Gentiles, III, 98–102, and De potentia, VI.
46 Summa theologiae, Ia, 83, 1 and On Evil, VI.
47 Summa theologiae, Ia, 82, 1.
48 Herbert McCabe OP, God Matters, London, 1987, p. 14.
49 The honest answer to the question is, ‘We do not know’. What follows is merely
an opinion based on what Aquinas actually said.
50 Cf. René Descartes, Meditations on First Philosophy. For modern presentations
of dualism see H.D.Lewis, The Elusive Self, London, 1982 and R.G.Swinburne,
The Evolution of the Soul, Oxford, 1986.
51 Summa contra Gentiles, II, 57, 3–5.
52 I take physicalism to be the belief that people are nothing but bodies operating in
certain ways. Cf. J.J.C.Smart, ‘Sensations and brain processes’, Philosophical
Review, 68 (1950): 141–56.
53 Summa theologiae, Ia, 75, 1.
54 Lecture on the first letter to the Corinthians, XV; cf. Summa theologiae, Ia, 77, 8.
55 Cf. Summa theologiae, Ia, 75, 6.
56 Cf. On Truth, XIX.
57 Anscombe and Geach [11.11] 100.
58 Summa contra Gentiles, IV, 82–6.
59 Cf. Summa theologiae, 2a2ae, 1, 4, ad. 2.
60 For Aquinas on the virtue of faith see Summa theologiae, 2a2ae, 1–16.
61 Marenbon [Intr. 10], 83ff.
62 Summa theologiae, 2a2ae, 1, 1.
63 Summa theologiae, 2a2ae, 1, 4–5.
BIBLIOGRAPHY
Original Language Editions
The most authoritative study in English of Aquinas’s works is I.T.Eschmann, ‘A
catalogue of St Thomas’s works: Bibliographical notes’, in Gilson [11.17]. It is
supplemented by ‘A brief catalogue of authentic works’, in Weisheipl [11.9]. The
definitive text of Aquinas’s writings is being published by the Leonine Commission,
established by Pope Leo XIII in 1880, which has already produced editions of Aquinas’s
most important works (e.g. Summa contra Gentiles, Summa theologiae). But the
work of the Leonine Commission is still unfinished.
Publication of Aquinas’s writings prior to the Leonine edition include Opera omnia,
Parma, 1852–73 (the Parma edition), and Opera omnia, Paris, 1871–82 (the Vivès
edition). Over many years most of Aquinas’s writings have also been published in
manual size by the Casa Marietti, Turin and Rome.
Translations
For a modern English translation of the Summa theologiae, with notes and
commentary, readers are best advised to consult the Blackfriars edition of the Summa
theologiae, London 1964–81. The translation is, unfortunately, sometimes
unreliable. For a more literal rendering of the text, see St Thomas Aquinas Summa
Theologica, translated by Fathers of the English Dominican Province, London, 1911
and Westminster, Maryland, 1981. For an English translation of the Summa contra
Gentiles see Saint Thomas Aquinas: Summa contra Gentiles, translated by Anton
C.Pegis, James F. Anderson, Vernon J.Bourke and Charles J.O’Neil, Notre Dame,
Ind. and London, 1975. The best modern translation of De ente et essentia is
Aquinas on Being and Essence: a Translation and Interpretation by Joseph Bobik,
Notre Dame, Ind., 1965. For other English translations of Aquinas, see the Brief
Catalogue in Weisheipl [1 1.9].
Bibliographical Works
11.1 Bourke, Vernon J. Thomistic Bibliography: 1920–1940, suppl. to The
Modern Schoolman, St Louis, MO., 1921.
11.2 Ingardia, Richard (ed.) Thomas Aquinas: International Bibliography 1977–
1990, Bowling Green, Oh., 1993.
11.3 Mandonnet, P. and Destrez, J. Bibliographie Thomiste, 2nd edn, revised by
M.-D.Chenu, Paris, 1960.
11.4 Miethe, Terry L. and Bourke, Vernon J. Thomistic Bibliography, 1940–1978,
Westport, Conn. and London, 1980.
Biographical Works
11.5 Ferrua, A. (ed.) Thomae Aquinatis vitae fontes praecipuae, Alba, 1968.
11.6 Foster, Kenelm (ed.) The Life of Thomas Aquinas, London and Baltimore,
Md., 1959.
11.7 Torrell, Jean-Pierre, Saint Thomas Aquinas, vol. 1, The Person and his Work,
Washington, DC, 1996.
11.8 Tugwell, Simon (ed.) Albert and Thomas: Selected Writing, New York,
Mahwah and London, 1988.
11.9 Weisheipl, James A. Friar Thomas D’Aquino, Oxford, 1974: republished
with corrigenda and addenda, Washington, DC, 1983.
General Studies and Introductions
11.10 Aertsen, Jan Nature and Creature: Thomas Aquinas’s Way of Thought,
Leiden, 1988.
11.11 Anscombe, G.E.M. and Geach, P.T. Three Philosophers, Oxford, 1961.
11.12 Chenu, M.-D. Towards Understanding Saint Thomas, trans. A.M.Landry
and D.Hughes, Chicago, 1964.
11.13 Chesterton, G.K. St Thomas Aquinas, London, 1943.
11.14 Copleston, F.C. Aquinas, Harmondsworth, 1955.
11.15 Davies, Brian The Thought of Thomas Aquinas, Oxford, 1992.
11.16 Elders, Leo J. The Philosophical Theology of St Thomas Aquinas, Leiden,
1990.
11.17 Gilson, Etienne The Christian Philosophy of St Thomas Aquinas, London,
1957.
11.18 Kenny, Anthony Aquinas, Oxford, 1980.
11.19 Kretzmann, Norman and Stump, Eleonore (eds) The Cambridge Companion
to Aquinas, Cambridge, 1993.
11.20 McInerny, Ralph St Thomas Aquinas, Notre Dame, Ind. and London 1982.
11.21 ——A First Glance at St Thomas Aquinas: a Handbook for Peeping
Thomists, Notre Dame, Ind. and London, 1990.
11.22 Martin, Christopher (ed.) The Philosophy of Thomas Aquinas, London and
New York, 1988.
Studies of Particular Topics
11.23 Boland, Vivian Ideas in God according to Saint Thomas Aquinas, Leiden,
1996.
11.24 Bonnette, D. Aquinas’ Proofs of God’s Existence, La Haye, 1972.
11.25 Hankey, W.J. God in Himself Aquinas’s Doctrine of God as expounded in
the Summa Theologiae, Oxford, 1987.
11.26 Henle, R.J. Saint Thomas and Platonism, The Hague, 1956.
11.27 Kenny, Anthony (ed.) Aquinas: a Collection of Critical Essays, London and
Melbourne, 1969.
11.28 ——The Five Ways, London, 1969.
11.29 ——Aquinas on Mind, London and New York, 1993.
11.30 Kretzmann, N. The Metaphysics of Theism: Aquinas’s Natural Theology in
‘Summa contra Gentiles’ I, Oxford, 1996.
11.31 Lisska, Anthony Aquinas’s Theory of Natural Law, Oxford, 1996.
11.32 Lonergan, Bernard Verbum: Word and Idea in Aquinas, ed. D.B.Burrell,
Notre Dame, Ind., 1967.
11.33 McInerny, Ralph Aquinas on Human Action, Washington, DC, 1992.
11.34 Owens, Joseph St Thomas Aquinas on the Existence of God: Collected Papers
of Joseph Owens S.Ss.R., ed. J.R.Catan, Albany, NY, 1980.
11.35 Person, Per Erik Sacra Doctrina: Reason and Revelation in Aquinas, Oxford,
1970.
11.36 Steenberghen, Fernand van Le Problème de l’existence de Dieu dans les
écrits de S.Thomas d’Aquino, Louvain, 1980.
11.37 ——Thomas Aquinas and Radical Aristotelianism, Washington, DC, 1980.
11.38 te Velde, Rudi A. Participation and Substantiality in Thomas Aquinas, Leiden,
1995.
11.39 Westberg, Daniel Right Practical Reason: Aristotle, Action, and Prudence
in Aquinas, Oxford, 1994.
11.40 Wippel, John F. Metaphysical Themes in Thomas Aquinas, Washington,
DC, 1984.
Routledge History of Philosophy.
Taylor & Francis e-Library.
2005.