lack of a human known answer does not mean something else must exist that knows the answerHowever, in your same vein of logic, the incapability to prove the existence of a designer does not invalidate the existence of a designer in the equation.
This same flimsy logic is applied within scientific naturalism, where we assume that because the existence of a designer is not capable of being proven, that the only way we can conclude something "coming about" is by inferring from only what is empirically given.
Surely you would not try to argue with me that because a child is not present (and thus logically unprovable to exist) that the existence of a sand castle on the beach could only be explained by the waves and functions of the ocean.
Obviously in that example we have external information to invalidate our faulty logic (i.e. seeing prior children build sand-castles), but it serves to highlight the absurdity that comes about when trying to infer from what is only empirically given. Now take that simple sand castle example and apply it to the insane complexity of trying to explain the creation of the universe. Not to mention remove the external information that enables us to validate/invalidate our claims.
I hope you can see why I choose to merge my intuition for recognizing intelligent design with empirical science.