I see no reason trying to explain things that are not part of the system. The world that surrounds us is a very large system, and due to its sheer size plenty of things are possible to happen which we can't notice, but on a larger time-scale it may make a great difference. If we happen to understand all the underlying principles and connections between all sorts of events (which will most definitely take us a while), we should be able to answer pretty much everything from within the system, without the need of using any external possibilities.
Those times are yet to come though, so we are pretty much playing a guessing game. But mind you, accepting "God did it" would be pretty much defying the human nature and the natural curiosity we were born with. We have to keep pushing for answers, as I'm certain that this is not the time when we can or have to stop progress.