DrChinese said:
No, there is no known analogous explanation.
1. Most quantum physicists do not think such exists, and current theory does not provide for such an explanation.
If it is not intial conditions, is probability itself thought to be acting on the photons, is it just left as an unknown, or is there some other cause postulated?
No one really knows. If you follow the interpretations of Quantum Mechanics, you will see that there are opinions all over the place. But everyone pretty well accepts that Quantum Mechanics, where it does speak, is correct.
So a lot of the interpretations are considered philosophical in some respects as the predictive results are all the same in every interpretation. Again, there are no shortage of viewpoints. That does not mean you are free to invent your own and it would be accepted: any interpretation that yields predictions different than QM wouldn't make sense. So there are significant constraints.