A common objection to the whole family of design arguments is the fact that any god which would have been able to create the universe would itself have to be rather complex and certainly couldn’t be “accidental.” So, if the universe and the human body is too complex to be accidental, what about this god? Who or what created this god?
Theists often respond by claiming this god is a “necessary being” and doesn’t need a “creator.” Unfortunately, this is unsupported and unsupportable. There is no basis for such an arbitrary assertion, except to try to excuse their god from the same standards they wish to apply to the universe. We haven’t observed that God is necessary. There are no tests that have been performed which demonstrate that God is necessary. The idea that God is necessary can’t be logically derived from any observations or tests. No, this is just an asserted attribute which theists pull out in order to counter this objection — it’s not based in reality, just theology.
Moreover, any excuse made for this god can be equally work for the universe. Why can’t the universe be “necessary” or not need a “creator?” No one can say — after all, we really don’t know enough about our universe or universes in general to make such a judgment. We have no idea whether this universe "had" to exist or not. Maybe it did, maybe it didn't.
With a sample size of one and so little knowledge about how it originated, no definitive conclusions can be asserted. At the same time, insisting that God is "necessary" while the universe isn't amounts to little more than "argument by definition." Merely asserting that God exists necessarily isn't the same as providing adequate grounds for believing this is true. Unfortunately, many apologists don't bother with the latter - they seem to feel that merely saying something is enough to warrant believing that it is true.
More on this point can be read in the article "Who Made God? An Atheological Argument from Design"
