Cosmological Argument
How do you prove the existence of god?
Aquinas came up with the ‘five proofs’. These are 5 ways you can prove without a
doubt God exists. The first 3 of the 5 are cosmological. The fourth of the 5 arguments
is the ontological argument, which is a priori argument. The 5th argument is what we
call the teleological argument.
A posteriori is what the cosmological argument is. The cosmological argument
attempts to infer or prove the existence of God from the existence of the cosmos and
the phenomena within it. The cosmos cannot have made itself, it says, therefore it
must be made by God. Plato and Aristotle had already said these ideas over 1000
years ago. In philosophy we have something called the Ockhams Razor theory, which
is that the simplest explanation must always be accepted. The cosmological argument
is the simplest explanation.
In the 13th century, Aquinas gave us the popular cosmological argument that we know
today. Famous philosophers like Descartes and Leibniz developed it further later on.
Leibniz wrote his book ‘Theodicy’ in 1710: ‘nothing takes place without sufficient
reason’. When we look at the universe of the cosmos science tells us how the world
was created, but it never tells us why it was created. He says that God gives us the
‘why’.
Modern day supporters of the argument are Craig and Swinburne. The opponents of
the argument are Hume and Kant.
Aquinas’s Ideas
Aquinas was around between 1225-1274, and he was later canonised [he became a
saint]. He is still highly regarded by Roman Catholics. Aristotle’s ideas were
fashionable in the 13th century, and so was the idea of applying philosophy to the
development of Christian thought. Aquinas tried to apply Aristotle’s ideas to
Christianity. He develops Aristotle’s idea of the Prime Mover. Aquinas’s book was
called the ‘Summa Theologica’ and was over 4000 pages long! He only devoted 2
pages in the whole book to the existence of God. It is because his explanation of this
was so short that it became popular, and was known as the ‘five ways’. The first way
is ‘the un-moved mover’, the second way is ‘the un-caused causer’, the third way is
‘possibility and necessity’, the fourth way is ‘goodness, truth and nobility’ and the
fifth way is ‘telos’ [purpose and design].
The First Way – the un-moved mover [the un-changed changer]
Aquinas discovered that in the universe there are all sort of causes and effects, there is
lots of movement and things change. Everything moves from ‘potentiality’ to
‘actuality’ – so everything has its potential, and then everything moves how it’s meant
to eventually. He said that what is potentially ‘x’ is not actually ‘x’, yet the actual ‘x’
can only be produced by something that is actually ‘x’. For example, an acorn is
produced by an oak tree, and will become an oak tree. Aquinas doesn’t like the idea of
infinite regression. Aquinas said that whatever is moved or changed must be moved or
changed by another which was itself moved or changed. He said that we have to go
back to something which itself was moved by no other, because infinite regression is
impossible. Swinburne uses this idea as well, and he teaches that God sustains the
universe, and that without God, the universe would cease to be. There must be an
initiator of the change whose continued existence is depended upon.
Problems with this argument:
 You can’t prove that there is no infinite regression.
 Even if things do go back to a starting point which created everything, it
doesn’t have to be in the form of the Christian idea of God. Neitsche said that
God is dead.
 The world may have no cause.
 If we are saying that we can’t infinitely regress because we can’t accept
infinity, there must be a starting point or a God. But then something must have
created God. How can we accept that God is an infinite being if we have just
rejected infinity?
 If numbers can go on and on forever then why can’t regression do the same?
The Second Way – the un-caused causer
This is similar to the line of argument of the first way, but it replaces the word change
with cause. Aquinas said that every effect has a cause. Nothing can cause itself
because it doesn’t exist before it is caused. Again Aquinas said that we cannot have
infinite regression, therefore we need an un-caused causer. This un-caused causer has
to be God. This fits in with Aristotle’s theory of the Prime Mover.
The Third Way – contingency [changing and dependent] and necessity [un-changing
and independent]
Aquinas said that everything has property, and everything is made up of something.
Everything is referred to as a being and everything in the world in contingent. [To link
it to Plato, everything in the world of senses is contingent. Plato said that everything
in the WOF is unchanging, whereas the material world is contingent]. This means that
everything comes into being [is generated] and perishes. It also points to the fact that
everything depends on the things around it. Aquinas goes on with his logical
argument to say that if all things are contingent, then at one time nothing would have
existed. There must be a point in history in which nothing existed, [Aquinas does not
accept infinity as a solution], and a time before everything came into existence. He
said that if this is so, how did things come into existence if nothing existed before
them. He said that everything has to have a prior cause.
Aquinas said, therefore, that not all things can be contingent. There must be one thing
which is not contingent but which is a necessity. That necessity, Aquinas concluded,
is God because God is outside the world of contingents [Plato]. His line of argument
follows:
 Stage one – some contingent beings exist
 Stage two – if any contingent being exists then a necessary being must also
exist
 Stage three – God exists as that necessary being
Problems with this argument:
 Even though this argument is logical and is the simplest explanation, there are
much deeper things to the argument that need to be considered.
 This argument depends on your belief in God.
 Why does there have to be a point where nothing existed?
 God cannot be the answer, because we don’t know why He/She created the
world.

There can’t be a reason for everything.
Other Forms of the Cosmological
1] The Principle of Sufficient Reason
A man called Leibniz in the 17th century avoided the problem of infinite regression.
He reinterprets history as an endless series of explanations, not events. He says that
even if the universe had always existed, there is nothing to show why it exists.
According to Leibniz, everything has a sufficient reason. He calls this God. In the 18th
century a man called Hume argued against Leibniz saying that just because each event
in the universe has a cause, it does not mean that the whole universe has a cause. In
1957 a man called Bertrand Russell supported Hume criticisms, and supported them
in this way; by saying that just because all humans have a mother, it doesn’t mean that
the whole of human kind has one big mother. Russell said this in his book ‘Why I am
not a Christian’. Here is a quote from this book: ‘the universe is just there, and that is
all there is to say’.
2] The Beginning Argument
This argument has its origins in Islamic thought of the 9th century, but it was
popularised in the west by a man called John Locke, in the 17th century, and a man
called William Craig in the 20th century. They said that everything that begins to exist
must have a cause. This cause must be transcendent, therefore it must be God,
because they said that everything has a cause, but there must be something outside of
this world with no cause. This has to be God. Sub-atomic physics can argue with this
point; it is found that electrons can pass out of existence at one point and pass into
existence at another point. A cosmologist would argue that this just shows how
limited our knowledge is, we just haven’t found the cause yet of these electrons, but
we will eventually find where these electrons have come from.
The cosmological argument revolves around the idea that the universe had a
beginning. Some people could support this argument with the big bang theory.
Nietzsche said that God could be the cause of it, but he could also cease to be.