For a start, it should be noted that the unmoved mover, for which Aristotle argues, is not a personal God, like that of Christianity, it has no religious significance, it is simply seen as the ultimate cause of the Cosmos. The concept of a personal God, perhaps, only becomes apparent when Leibniz takes the argument further with his ‘Principle of Sufficient Reason’. This states that everything, including the universe itself must have a reason for its existence, and that this must mean that there is an ultimate, uncaused cause – God.

There is a compelling logic in both of these arguments. In fact, they serve to heighten the believer’s understanding of God’s omnipotence and transcendence. However, the unbeliever may find them less convincing. David Hume said that it was wrong to go from saying that all events in the universe have a cause to saying that the universe itself must have a cause, in the same way that it is wrong to say that every human being has a mother so that therefore the human race must have a mother! Bertrand Russell was equally cynical, believing the universe to be just ‘a brute fact’. However, one could argue that they both miss the point. Leibniz and Aquinas did not argue that because every event in the world had a causal explanation, the series of events that made the world also required a causal explanation. Leibniz simply believed that a sufficient reason, or cause, was needed to bridge the gap between something and nothing. Similarly, Aquinas believed that you could not have a series of events, each explained by something prior to it, without wondering how the entire chain started in the first place. Frederick Copleston believed that it was difficult to respond to Hume and Russell when they both refused to stick their necks out, ‘If one refuses to even sit down at the chess board and make a move, one cannot, of course, be checkmated.’

However, the argument is flawed in other ways. The argument from motion does not work with the scientific knowledge that we now hold today. We have presumed that actual x can only be brought about by x, but we now know that two cold objects can be rubbed together to produce heat. However, one could ask what this proves – it might prove that heat does not need to be caused by heat itself, but it does still have a cause, and it still requires energy. Equally, it has also been argued that the Big Bang could be the uncaused causer, as the explanation works in exactly the same way as if we are talking about God. This goes hand-in-hand with John Hick’s question, ‘Why should the argument stop with God? Why should God not in turn need to be explained?’ Therefore, perhaps the Cosmological Argument need not look beyond the Big Bang. One could even argue that such a view is what Aristotle was proposing from the start. However, Leibniz took the argument further when he spoke of a ‘Sufficient Reason’ and the Big Bang does not appear to provide this.

In conclusion, the strengths of the original Cosmological Argument, as argued by Aristotle, appear to be immune to criticism. However, one might wonder what exactly it proves, in this guise, – besides the fact that the universe must have had some kind of origin greater than itself. The argument only supports the view of a personal, even Christian God, when one examines Leibniz’s development of it. This is open to greater criticism, as we might ask what evidence there is to suggest that anything in the universe has a purpose – Natural Law struggles, on greater inspection, to tie any one thing down to a particular purpose. However, cosmologists have tried to take the argument beyond an impersonal ‘God’, a mere cause of the cosmos, when the philosophy is twinned with the teleological argument. At that point, one could argue, we not only have an omnipotent God, but a benevolent one, also.