1 Summary: Unmoved mover – everything that moves is moved by something:
Clock / pendulum
And expanding universe
Uncaused cause – everything which is caused is caused by something
2 Aquinas’ 3rd Way: possibility and necessity
If the universe didn’t exist at some stage in the past then two states equally possible: existence and non-existence;
For something then to come into existence it needed to be willed by something;
For us that’s like the decision between a holiday in Wales and in Tunisia; or most of the time willing a baby into existence requires a deliberate act of love and commitment!
The universe exists therefore something had to will it into existence – that something is God.
Nothing is responsible for its own existence; if not you then your parents…logically then at the start something outside the universe – God.
Therefore if the condition of existence is only a possibility there must be a necessary being who is not like us contingent upon others for existence, but outside of it and whose existence is necessary for all others to occur.
So Aquinas said God is that necessity: a necessary Being; it is impossible for God not to exist.
Or as Copleston put it, He is “a being that must and cannot not exist.”
Swinburne likewise agreed: if there is a starting point to time then something caused time and space to exist outside of that time and matter – that something is God.
Evidence from the bible comes in the form of God’s description of himself as given to Moses: “I am.” This implies eternally present and existent.
3 Arguments against
Objectors would say if everything has a cause so should God – you are making a special case by exempting him.
Hume called the conclusion – God- a “leap too far.”
Russell regarded the analogy as stretched as if you said well each of us has a mother then the whole human race has a mother. It is an error of degree.
What’s wrong with infinite regress; negative numbers go back infinitely.
Hume also said that even if there had to be a first cause why did it have to be God.
4 Leibniz and the Principle of Sufficient Reason
Need for an absolute cause – no need to back beyond it if it sufficiently answers the question; e.g. why did you break his nose? Because he insulted my football skills, because I let a goal in, because I fell over…..because my parents had me! Unnecessary!
Therefore God is sufficient reason no need to go beyond.