The Cosmological Argument

Definition and history:

St Thomas Aquinas 1224-1274 – The 5 Ways

  • The argument from an unmoved mover
  • The argument from an uncaused cause
  • The argument from possibility and necessity

Cosmological = cause

This is the attempt to argue from the fact of the world’s existence to –-a transcendent creator.

This argument is an a posteriori argument – this means that the conclusion is drawn from available evidence or experience.


Arguments in favour:

Aquinas‘ first argument is based on the ‘fact’ that everything that moves is moved by something, but that this chain of moves cannot be infinite – there must have been a time when there was no movement and a time when that movement started. Something outside that movement must exist to will that movement into being and that something we call God – he is the unmoved mover.

Aquinas also believed that all events have causes and since things come into existence and then later cease to exist, at one time none of them existed. However if at one time nothing existed then there must have been an original event to cause something to exist and from which all others stem –– he believed that this was a being – a being which is necessary but whose being is not dependent or contingent on a cause itself – he believed that this first event or cause must therefore be God. He is therefore the uncaused cause and the necessary being.

Between the 9th and 12th centuries AD, al-Kindi and al-Ghazali, two Muslim philosophers expanded the argument.

Simply put:

  • Everything that exists must have a cause for its existence,
  • The universe exists
  • Therefore the universe must have a cause.

Both these arguments assume that:

  • An infinite number of causes cannot exist – this is called infinite regress – (think of the chicken and egg argument!)
  • Therefore they must be finite,
  • Therefore at some time in the past the world began to exist,
  • Therefore there was a time when either of the two states was possible – that there should or should not be a universe!

Al-Ghazali argued that when two states are equally possible then the one which comes about must be willed by a personal agent – i.e. God.



It all boils down to the idea that nothing can be responsible for its own existence and that therefore a first cause was necessary – that is God.


Arguments against:

There are flaws in this argument.

Kant argued that the whole notion of cause and effect was one of the ways our minds interpret the world, because that is the way our lives are lived and therefore an uncaused cause is a mental impossibility to envisage

Hume 1711-1776 said that we observe an event happen before a consequence and separate the two into cause and effect. But in the case of the world we cannot get outside it to watch it objectively. Since we have seen no other worlds can we assume the same cause? (E.g. just because gravity works on our world does it necessarily mean it does on all?)

He saw nothing necessarily wrong with infinite regress – to look for a cause for the whole was to be unnecessarily pedantic. Our minds are too limited and just because we cannot grasp the idea doesn’t necessarily make it impossible!

Hume also said : ‘we can never ascribe to the cause any qualities but what are exactly sufficient to produce the effect.’

What this means is that even if we go along with the idea that there is/ was a first cause why do we necessarily have to call that God?? Or if we call that first cause God why do we have to ascribe to God qualities other than those just needed for creation??



Aquinas knew the limitations of his argument – in response he argued:

‘Any effect of a cause demonstrates that its cause exists…the central link is not what the cause is…but what the name of the cause is used to mean; and as we shall see the word God derives from his effects.’


More recently Richard Swinburne starts at the other end of the argument and asks if there is a personal God, why has he made the world the way it is?

‘God has reason to make an orderly world because beauty is a good thing.’


There is much beauty in the world but it does not have to be here for our survival. Because it is, therefore, there must be more than just some uncaring, automatic, physical process at work behind the universe, this is good and this is what we mean by God!

The philosopher Bertrand Russell famously argued that the existence of the universe was simply ‘Brute fact’, it just is, and that’s it! There is nothing to be gained by making more of it than that!



Aquinas knew that his arguments did not prove that there is a God who is the prime mover, but they do point to the sort of reality a religious person is thinking about when he/she uses the word God. Not one cause among many others but that which lies within and yet beyond all of them.

[Anselm defined God as the greatest being imaginable… ‘that than which no greater can be thought.’]


Points for further consideration:

The Big Bang

A Mobius strip

Inductive arguments – i.e. ones in which the conclusion is not contained within the premises of the argument and therefore it could be wrong! (Burglar…)


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