2001 (a) Describe the main strengths and weaknesses of the cosmological argument for the existence of God. 
The cosmological argument was most notably propounded by Thomas Aquinas in the first three of his five Ways. In the first two he suggested that all things that are moved are moved by something and that all effects need a cause and that the first mover and the first cause are God.
This argument was refined by two Muslim scholars in the Kalam argument: that everything that exists has a cause; the universe exists; the universe must have a cause; that cause is God.
In Aquinas’ third Way he suggested that God was a necessary being on the basis that we are all contingent beings, that is, we are dependent on our parents for our existence and following the chain back logically to its beginning there must be something outside of the chain upon which all contingent beings are dependent but which is not itself dependent upon anything else for its existence. That is a necessary being and that is God; he is self-causing and self-sustaining.
Among the strengths of this argument are the fact that it is a posteriori, based on evidence; on the observation and experience of our senses. We see cause and effect; we see things come into existence and then die. It is logical then that the universe likewise had a beginning and a cause. However there are two weaknesses here. One is that, as Hume pointed out, cause and effect may not in fact be linked it may just be our way of interpreting the evidence. “We observe an event and a consequence and separate the two into cause and effect. But because we are limited and cannot get outside the universe, so we cannot assume they are always linked.”
And the second is that the analogy becomes too stretched; it is a leap too far from individual causes for specific things to one cause for all things.
Another weakness of this argument is the assertion that God is a necessary being. By making God the only thing in the universe that is not caused we are making Him into a special case and to say that God just has to exist, is not a legitimate defence. In addition it is also weak to assume that just because we cannot explain the cause of the universe yet that we need to look outside the universe for an explanation of it.
A strength in this argument is that philosophers are aware of man’s need for answers to life’s most difficult questions and as Leibniz suggested in his principle of Sufficient Reason that God was a good enough reason for the existence of the universe and there is no need to look beyond Him for a further answer and it could be argued that until a better explanation comes along this conclusion should suffice.
However another weakness of this argument lies in that it rests on the assumption that there cannot be an infinite chain of causes and effects, infinite regress. But why not? Again just because our human minds are too limited to grasp it doesn’t mean it cannot be.
Above all, the major weakness is the adoption of just one of a number of conclusions which could be drawn from the same evidence and even if we agreed with the intermediate conclusion the final conclusion: God, is still reliant on faith and is not a logically necessary conclusion.
2001 (b) To what extent do the weaknesses of this argument limit its effectiveness?
The weaknesses of this argument are stronger than the strengths which greatly limits the effectiveness of the argument.
This is because the whole argument is based on the evidence that cause and effect go together. Although this seems likely it is not certain that every single effect that has ever happened has had a cause. Hume argued that the link between the two was not proven. He regarded cause and effect as concepts linked together by our need to impose order on the world. It also stretches the analogy too far to suggest that because we all individually have mothers, that the whole human race has a mother. Therefore the argument is not conclusive.
Secondly who says the universe hasn’t always just existed, as Bertrand Russell suggested? Infinite regress is only logically improbable based on our experience but this does not make it impossible. Just because we cannot get our heads round an infinite chain of cause and effect does not mean it can’t be true.
A major problem with this argument is its circular logic and the apparent contradictions which lie within it. It begins from the assumption of God’s existence and then sets out to use the fact of His existence to prove His existence! As Copleston said ‘a being that cannot not exist,’ is something that can only be acceptable to those with pre-existing faith.
And Hume again argues that even if there was a first cause why does it have to be God? It is an inductive argument and therefore more than one conclusion can be drawn. In addition the cosmological argument is an a posteriori argument which is strong in the sense that it is based on evidence but that evidence can be interpreted to form more than one conclusion. Perhaps God isn’t the reason for the universe perhaps it has a more prosaic cause such as the big bang. And as Hume said: “We can never ascribe to a cause any qualities but what are exactly sufficient to produce the effect.”
Of course the strengths of the argument can help a person who already believes to have a firmer foundation for their beliefs but for the atheist the weaknesses, particularly in the absence of any definite proof, will never convince them of the existence of God. And the theory of Ockham’s Razor which states that the simplest explanation for anything is usually the correct one, which seems to suggest that God is the simplest explanation, is not logically satisfying to non-believers. However to do as Russell suggested and not discuss it, that the universe ‘just is. Brute Fact’, is not satisfying either.
This argument is an attempt to explain why there is something rather than nothing but even Aquinas knew that this argument could not absolutely prove the existence of God, it remains, therefore, a matter for faith.