the existence of God as demonstrated by St. Thomas Aquinas
Introduction
The knowledge of God is
at the peak of metaphysics. By God here we mean a Supreme Being who exists
whether or not humanity exists. Immanuel Kant opines that some concept of God
is essential at the start of any proof for the existence of God. The Dominican
Walter Farrell supports this view.[1]
St Anselm says that God is “that than which nothing greater can be conceived.”[2]
This paper, however, focuses on the existence of God as demonstrated by St.
Thomas Aquinas. First, we shall discuss the arguments for the existence of God
before the time of St. Thomas Aquinas, for St. Thomas and others.
1.0 The Arguments for the Existence of God
before the Medieval Period
That God is understood as
someone who creates what comes into existence is a continuing conviction in
Judaism, Christianity, and Islam.[3]
The first notions of deity were expressed in the Iliad and Odyssey of
Homer. In these epics is found a hierarchy of gods governing the universe. The
ruler of the gods and mortals was Zeus who was not considered the creator of
the universe. His Roman equivalent was Jupiter. Other gods and goddesses in the
Greek pantheon include Athena (the goddess of arts and crafts) and Apollo (the
god of prophecy, medicine and archery.[4]
Zeno, Parmenides and Melissus share the view that all things are always at rest
and nothing is ever in motion. Heraclitus posits that all things are always in
motion. These views pose a challenge to the principles of natural philosophy.
The latter because it says that there is no such thing as rest in the universe
and the former because it says that nothing is ever in motion. In his search
for the eternal, Plato says that only that which is beyond the universe, space
and time could be regarded as the ultimate reality. God, therefore, for Plato,
was the Idea of the Good.
It bears pointing out that Aristotle disproves the view
that all things are apt to be in motion and to rest and that nothing is either
always in motion or always at rest. He refutes this by establishing the
existence of an immobile first mover. In any series of moved movers, according
to Aristotle, we must come to a first unmoved mover. He viewed the Eternal as
the “Prime Mover” and “Uncaused Cause.” Moreover, Aristotle also claims that
man is aware of his finitude. Why? This is because God is continually
impressing man with His infinitude. Therefore, the sense of finitude itself is
proof that an infinite being, God, exists.[5]
Aristotle claims that it is not possible for anything of
finite power to cause motion for an infinite time because infinite power cannot
exist in anything material (magnitude). Moreover, Aristotle was clear on
gravitational motion which is not self-motion since self-motion is proper to
animate bodies which can start or end their motion but heavy bodies are not animate
and must fall if there is no impediment. Hence, the gravitational motion of
heavy things is natural because they have in themselves the principle of their
motion which is in potency to such-and-such an act. It is noteworthy to state
that everything moved is moved by another, but not always here and now because
both natural motion (gravitational or self-motion) and compulsory as in a
projectile last in the mobile after the mover has conferred on it motion.
Furthermore, in view of the fact that there is no infinite series of moved
movers argues for the immobility of the first mover from the perpetuity of
motion. For Aristotle, therefore, there is a single continuous perpetual motion
which accounts for and is prior to all earthly generation and corruption.[6]
Because St. John of Damascus says that the “knowledge of
God is naturally implanted in all people”, some say that the existence of God
is self-evident. But Thomas Aquinas in his Summa
Theologiae or “Summary of Theology” claims that the existence of God is not
self-evident to us. However, the statement “God exists” is self-evident in
itself because the predicate is the same as the subject. In other words, God is
His own existence. Though the existence of God is not self-evident to us, it
can be demonstrated through his effects. It is to St. Thomas Aquinas’ Quinque Viae (Five Ways, or Five proofs)
for God’s existence that we now turn.
2.0 Thomas Aquinas on God’s Existence
In the first part of his Summa Theologiae, St. Thomas Aquinas
treats of God, who is the “first cause, himself uncaused.” The five proofs he
propounded are: the argument from motion, the argument from causation, the
argument from contingency, the argument from the degrees of perfection and the
argument from design. These proofs are discussed below.
2.1 The First Way: The Argument from Motion (Ex Motu)
Life is in motion.
Neutrons, electrons, protons and atoms are also moving or changing. Thomas
employs his knowledge of Aristotle’s potentiality and actuality in order to
explain the existence of God from motion. Everything which moves goes from
potentiality to actuality. It is an actual motion that converts a potential
motion into an actual motion. Each thing is moved by something else but this
sequence of motion cannot extend ad
infinitum. Thus, it is necessary to arrive at a first mover, put in motion
by no other and this first unmoved mover is what we call God.
2.2 The Second Way: The Argument from
Causation (Ex Causa)
The second way Thomas
Aquinas tried to prove the existence of God is from the fact of causation. In
the world perceptible by the senses, there is a series of efficient causes of
things. The efficient cause of a thing is that which causes change and motion
to start or to end.[7]
Nothing exists prior to itself. It follows that nothing is the efficient cause
of itself. If the first thing in a series of things does not exist, nothing in
the series exist. It is quite apparent that above all causes, there must be a
cause whose proper action is to give being. Therefore, it is necessary to admit
a first efficient cause, a First Cause or Uncaused Cause to which we give the
name God. Everything besides God derives its being from God.[8]
2.3 The Third Way: The Argument from
Contingency (Ex Contingentia)
The argument from
contingency is grounded on the distinction between possibility and necessity.
It is possible to be and it is also possible not to be. This is true because
all contingent beings come into being and go out of being. People are born and
people die. If everything has contingent existence, then a time will come when
everything will no longer exist. Thus, we cannot but postulate that there must
exist something the existence of which is necessary. The existence of this
being is not contingent on any other being. This being is God.
2.4 The Fourth Way: The Argument from
Gradation of Being (Ex Gradu)
It is quite observable in
the universe that some things are better, nobler, and truer than other things.
There are varying degrees of perfection in the world. Hence, there ought to be
something which is good, true and noble to the greatest degree. Aristotle says
that whatever is greatest in truth is greatest in being... the maximum in any
category is the cause of everything else in that category.[9]
There must be something which is to all beings the cause of their being,
goodness, and every other perfection and this we call God.
2.5 The Fifth Way: The Argument from Purpose
or Design (Ex Fine)
The argument from design
follows from the occurrence of things in the world. It is observable that
things, animate and inanimate, conscious and unconscious tend toward an end. Is
it not the case that whatever lacks intelligence cannot move towards an end,
unless it be directed by some being endowed with knowledge and intelligence. In
other words, since natural things have no knowledge, there must be some
previously existing intelligence directing them to an end like an archer who
gives a definite motion to an arrow so that it will wing its way to a
determined end.[10]
As a result, the world is governed by the providence of that intellect which
gave this order to nature and one may compare the providence by which God rules
the world to the political foresight of the president of a country or to the
monarchical foresight of a king or queen of a kingdom. Also, since different or
discordant things cannot always or for the most part be parts of one order
except under someone’s control but in the world, things of different natures
are under one control, under one order and this is not accidental. Thus, there
must be a super intelligent being by whose providence the world is ordered and
governed. This being we call God.[11]
3.0 Other Arguments for the Existence of God
Certainly, there are
other arguments on the existence of God apart from those of St. Thomas Aquinas.
Some of these arguments are considered in order to give us a bird’s-eye view of
the prevalent arguments on the existence of God.
3.1 The Argument from the Big Bang
According to the reigning
scientific opinion of our day, the Big Bang Theory was the beginning of the
physical universe, including not only matter and energy, but space, time and
the laws of Physics. Originated by Edwin Hubble in 1929 and backed by
discoveries in astronomy and physics, the Big Bang Theory presents the view
that the universe was once very compact, dense, and hot. At about 15 billion
years ago, a great explosion began the expansion of the universe and it is this
explosion that is identified as the Big Bang. William Lane Craig says that “at
some point in the past the entire known universe was contracted down to a
single mathematical point, from which it has been expanding ever since.”[12]
It is worth stressing that what existed prior to the Big Bang is unknown. But
did the universe created itself? We think, as well as we believe, that
something outside the universe caused the universe to exist and this something
we call God. No doubt, Craig claims that “the Big Bang represents the creation
event; the creation not only of all the matter and energy in the universe, but
also of space and time itself.”[13]
It is necessary to understand that as more researches and observations are
made, the Big Bang Theory is constantly being improved. What about the proof of
God’s existence from mathematical reality?
3.2 The Argument from Mathematical Reality
In her book, 36 Arguments for the Existence of God,[14]
Rebecca Newberger Goldstein explains the existence of God from mathematical
reality. She claims that the fundamental question in the philosophy of
mathematics is how can mathematics be true but not empirical? Mathematical
truths are necessarily true but the truths that describe our physical world are
empirical and truths that require empirical evidence are not necessary truths.
Furthermore, the truths of our physical world cannot explain mathematical
truths because mathematical truths exist on a different plane of existence. It
seems to be the case that only something which itself exists on a different
plane can explain mathematical truths. This something is only God. Hence, God’s
existence is deduced from the trans-empirical existence of mathematical
reality.
Conclusion
In view of the above
presentation, it seems reasonable to conclude that the existence of God can be
proved from reason alone. Though other arguments for and against the existence
of God abound, for instance, William Paley’s argument from design and the
argument from the problem of evil by John Stuart Mill, the arguments we
discussed above are of great importance in arguing for God’s existence.
Perhaps, the greatest contribution of St. Thomas Aquinas is his articulation
that whereas all things have a borrowed existence, God alone is subsistent
being, the only necessary being who cannot not be. It should, however, be noted
that the supreme revelation of God is found in Jesus Christ and, therefore, the
arguments we presented above, no matter their significance, do not negate the
great importance of faith in God as revealed in Christ.
[1] Walter
Farrell, A Companion to the Summa,
vol. 1(London: Sheed and Ward, 1941), p. 32.
[2] St. Anselm’s
ontological argument is found in chapters 2-4 of his Proslogion, in The Religion
of
Science Library, 4th ed. (New Jersey: Prentice-Hall, 1990),
p. 20.
[3] God’s
identification of himself as “I Am Who I Am” (Exodus 3:13-14) has been interpreted
as
“It is
He Who Creates.” See W. F. Albright, Yahweh
and the Gods of Canaan (New
York:
Doubleday, 1968), p. 148.
[4] Cf.
See Microsoft Encarta, Ancient Greek and
Roman Gods, Microsoft Corporation, 2009.
[6] Cf.
See Joseph Kenny, Lesson Notes on
Philosophy of Nature, chapter 12.
[7] See
Aristotle, Physics II 3.
[8] Cf.
Thomas Aquinas, Summa Contra Gentiles, II,
ch. 15.
[10] Cf.
Thomas Aquinas, De Veritate, q. 5, a.
2.
[11] Cf.
Thomas Aquinas, Summa Theologiae, I,
q.2, a. 3.
[12]
William Lane Craig, Reasonable Faith: Christian Truth and Apologetics,
(Wheaton, Illinois:
Crossway Books,
1994), p. 101.
[13] Ibid., pp. 101 – 102.
[14] Rebecca
Newberger Goldstein, 36 Arguments for the
Existence of God (New York: Pantheon
Books, 2010).
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