God as first cause
One of the common arguments for the existence of God is the assertion of God as first cause. In other words, the presence of a finely-tuned created universe implies the presence of a creator (Rees, 2003).
However, the common rebuttal to this is that if God had created the universe/world/nature, what/who created God (Dawkins, 2006)?
This is a retort makes two suggestions:
1) That the answer of "God" only pushes the question of origins one step further back.
2) That a complex god that could create a complex creation is sufficiently complex enough to require an explanation.
Biblical interpretation
Christian doctrine generally teaches that God is eternal and thus have no origin (eg: Psalms 90:2 and Psalms 90:4). To put it simply, God is the creator of time, and can exist outside time and thus is able to see the history itself.
On the other hand, some Bible scholars has pointed out that God is portrayed in Scripture as acting in time (Boyd, 2007). For instance, in Genesis 18, Abraham negotiated with God over the fate of two evil cities. Nevertheless, there is no compelling reason why God cannot exist out of time and be able to act within it at the same time.
The infinite regression problem
Answers from the Bible are very unlikely to convince the unbeliever. While many belivers find it satisfying as a solution to an infinite regression problem (if A was created by B, who was created by C, who was created by D... who created E, F, G,.... etc), some non-believers view the "God" answer as a cope-out to avoid questions about origins. If pointed out that God just came to be (ie God as first-cause and self-existant), it can be argued that the same is true of the universe.
However, if the universe did not have a cause, it would be immense difficultly to discuss the origin of the universe as a concept. While it may be argued that the universe "just came to be", it would also hardly be the satisfying answer the sceptic would seek.
Rephrasing the question
Ultimately, the nature of the questioner (both the theist and the atheist) must presume something-- whether everything, including the universe has a cause. If so, then the theist must somehow defend "God" as his answer, while the atheist will be left to the problem what the first cause is.
However, if not everything needs to have a cause, then the question of "who created God?" is meaningless.
Also check out:
Biologos
References
Dawkins, R. (2006) The God Delusion
Boyd, G. (2007) God of the Possible
Rees, M.J. (2003) Just Six Numbers: The Deep Forces that Shaped the Universe
