"Supernatural cause" is oxymoronic, a contradiction in terms. And you don't explain anything by positing the biggest unsolvable mystery in the universe. If science and philosophy can't explain something, why think that ancient religious myths can do better?

Indeed, it's scientistic to think that religion should be in the explanation business. That's what religious myths used to be for, before the Scientific Revolution. But religion also performs social functions in reconciling us to life and to the universe. Religion operates at an existential or "spiritual" level, not properly at an intellectual, philosophical, or empirical one. Christianity mixes this up, of course, by historicizing or literalizing its mythic protagonist.