Who made God?

Some atheists think they can dismiss cosmological arguments by simply asking, "Who made God?" Here's some observations that are pertinent to that riposte:

All the beings we observe seem to be contingent beings; some of them certainly are. It seems reasonable, therefore, to suppose that the following statement is true: 

There are some contingent beings.

Now if the Principle of Sufficient Reason is correct, there is some explanation of the truth of this statement, some answer to the question "Why are there contingent beings?" But what would an explanation of the existence of contingent beings look like? One possible explanation of this state of affairs is the following:

Something necessarily existent, some necessary being, is in some way responsible for the fact that there are contingent things.

This is not, of course, a very detailed explanation, but it seems to be a perfectly satisfactory explanation as far as it goes. It is conceivable that someone might object to it on the ground that it "merely pushes the problem of the existence of things back a step." The worry here is something like this: "All right, the necessary being explains the existence of contingent beings, but what explains its existence? Why does it exist?" But to say this is to neglect the fact that a necessary being is a being whose nonexistence is impossible. Thus, for any necessary being, there is by definition a sufficient reason for its existence: there could hardly be a better explanation of the existence of a thing than that its nonexistence is impossible 

As to the fact that the explanation is almost wholly lacking in specifics, we should note that there are few if any explanations that could not be given in greater detail. The explanation could be "filled in" in various ways… P. van Inwagen, Metaphysics, (Westview Press 2015), 160-61.

i) Some atheists might object that to define God as a necessary being begs the question. That's defining God into existence. Truth by definition. 

ii) But that objection is ill-conceived. To begin with, a debate over God's existence is, in the first instance, a debate regarding the idea of God. What does "God" represent? At that stage of the argument there's nothing wrong with a stipulative definition. To define God as a necessary being doesn't mean God necessarily exists, but that if there's a God, he exists of necessity. In other words, this is a statement about the concept of God under review. Whether there's a reality corresponding to that concept is another stage of the argument, but the idea of God is the idea of a necessary being.

And I mean the idea of God in classical theism, since that's the typical target of Western atheists, as well as what their Christian opponents typically defend. Of course, if this was a debate about Hinduism, then the definition would be different.

ii) In addition, this is not an arbitrary principle. What makes contingent entities contingent is their dependence on something else for their existence. It's possible for them not to exist. They didn't always exist, and some of them cease to exist. 

This in turn raises the question of whether it's possible for everything to be contingent, or must there be something necessary to ground contingent entities? Can it be contingency all the way down? Or must there be something which cannot fail to exist that supports everything else?  That, of course, is a hotly contested issue. But whether or not we can prove that possible things require something necessary, that is, at the very least, a reasonable explanation. If there's something necessary on which contingent entities depend, then that's a straightforward explanation for why they exist, since there's nothing in themselves that requires their existence. 

iii) By the same token, it's not unreasonable to think that the explanatory regress must terminate at some point. Indeed, that's a presupposition of science. But the question is where to draw the line. Some stopping-points are arbitrary or premature. My parents are not the ultimate source of my existence, since they have parents, and grandparents. Moreover, their physical existence is contingent, not merely on their parents, but the earth and the universe. 

iv) This eliminates facile counterexamples like Russell's Teapot and "one fewer god". Russell's Teapot, if it existed, would be a contingent object. So it doesn't have the same explanatory power as a necessary being like God. By the same token, heathen deities are contingent beings.