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Aquinas’ 1st and 2nd ways
- Aquinas created three versions of the cosmological argument.
- 1st way: motion
- Everything is in motion
- There can’t be an infinite regress of motion. It cannot be that there is just an infinite chain of movers going back in time forever. There has to have been a first mover – a start to the motion we observe.
- E.g. if you see dominoes falling, there must have been a first one that was pushed – there couldn’t have just been dominoes falling forever.
- So, there must have been a first mover that was unmoved – that is God.
- 2nd way: causation
- Everything has a cause
- There can’t be an infinite regress of causation – there can’t be an infinite chain of cause and effect going back in time forever.
- There has to be a first cause which is uncaused – that is God.
Hume’s critique of the cosmological argument: objection to the causal principle
- The causal principle is the claim that everything has a cause.
- The cosmological argument assumes that everything has a cause – it assumes the universe must have a cause.
- But Hume claims it’s possible the universe had no cause.
Evaluation: criticism of Hume’s objection to the causal principles
- However – it seems scientifically justified to think everything has a cause `
- Everything we’ve ever seen has a cause.
- So, it’s empirically more reasonable to think the universe also has a cause than to think it doesn’t.
- The cosmological argument is therefore still convincing.
Aquinas’ 3rd way: contingency
- A contingent being is one which depends on something else for its existence.
- Everything we see is contingent.
- There can’t have been an infinite regress of contingent beings – one creating the next, going back in time forever.
- So, there must have been a first contingent being, but that can’t come from nothing, so there must have been a necessary being which created it.
- That necessary being is God. (A necessary being does not depend on anything else for its existence).
Hume & Russell’s critique of the cosmological argument: fallacy of composition
- The fallacy of composition states that just because something is true of the parts, doesn’t mean it is true of the whole.
- E.g. just because every human has a mother, it doesn’t mean the whole human race itself has a mother.
- Similarly – just because all the parts of the universe have a mover/cause/contingency – that doesn’t mean the whole universe itself has a mover/cause/is-contingent.
- If the universe has no cause/mover/contingency, then there is no need for a God to explain its existence.
Evaluation: criticism of the fallacy of composition
- Leibniz points out that It’s illogical for something to happen without a reason/cause.
- The universe must have a cause – nothing comes from nothing.
- Something only comes from something.
- So, the universe must have come from some cause – God.
Hume’s critique of the cosmological argument: the possibility of an infinite series
- Maybe an infinite regress actually is possible.
- For something to be impossible it has to be logically self-contradictory.
- But there doesn’t appear to be anything illogical or nonsensical about things going back in time forever.
Evaluation: criticism of the possibility of an infinite series
- Dominoes example – shows things must have a beginning.
- If you see dominoes falling – there must have been a first one which was pushed.
- Similarly, if you see things in the universe changing, being caused or being contingent – there must have been a first one which started the process off but was not caused, moved or contingent.