What caused God?

The cosmological argument is not trying to show that there is a cause of things which just happens not to have a cause. It seeks to show if there is an ultimate explanation of things, then there must be a cause of everything else which not only happens to exist, but which could not even in principle have failed to exist. And that is why it is said to be uncaused - not because it is an arbitrary exception to a general rule, not because it merely happens to be uncaused, but rather because it is not the sort of thing that can even in principle be said to have had a cause, precisely because it could not even in principle have failed to exist in the first place. And the argument doesn't merely assume or stipulate that the first cause is like this; on the contrary, the whole point of the argument is to try to show that there must be something like this. Different versions of the cosmological argument approach this issue in different ways. Aristotelian versions argue that change - the actualization of the potentials inherent in things - cannot in principle occur unless there is a cause that is "pure actuality," and thus can actualize other things without itself having to be actualized. Neo-Platonic versions argue that composite things cannot in principle exist unless there is a cause of things that is absolutely unified or non-composite. Thomists not only defend the Aristotelian versions, but also argue that whatever has an essence or nature distinct from its existence - so that it must derive existence from something outside it - must ultimately be caused by something whose essence just is existence and which qua existence or being itself need not derive its existence from another. Leibnizian versions argue that whatever does not have the sufficient reason for its existence in itself must ultimately derive its existence from something which does have within itself a sufficient reason for its existence and which is in that sense necessary rather than contingent. And so on. So, to ask "What caused God?" really amounts to asking "What caused the thing that cannot in principle have had a cause?", or "What imparted a sufficient reason for existence to that thing which has its sufficient reason for existence within itself and did not derive it from something else?" And none of these questions makes any sense. One might say he isn't convinced the cosmological argument succeeds in showing there really is something that could not in principle have had a cause, or that is purely actual, or that has a sufficient reason for its existence within itself. He might even try to argue there is some sort of hidden incoherence in these notions. But merely to ask "What caused God?" - as if the defender of the cosmological argument had overlooked the most obvious of objections - simply misses the whole point. A serious critic has to grapple with the details of the arguments. He cannot short-circuit them with a single, simplistic question.