1) Creationists/Intelligent Designers insist that the Theory of Evolution is "just a Theory" but have no problem with the Theory of Relativity being a "just" a "Theory". DUH! There is no use arguing with them as they insist and do not think about "it" any.
2) As for anything "outside" the universe creating the universe: that is a VERY OLD bit of nonsense. The “all” includes all and has no outside and contains all times and all spaces by definition. That includes all causes of any and all things by definition. The universe or the “all” includes all creations and creativity by definition. There is nothing “left over” to “cause” the universe, no space “left over” for the universe to be in, and no “time” for the universe either. This is an old-old-old argument for the incommensurability of god developed in the 1100’s by monastery monks and need not be debated anymore. [The very same monks also developed the notion of uncountable infinite numbers by the contemplation of the number of possible incommensurate angels dancing, as angels do not “stand around”, on an infinitely small space.] As god could have no precursor, god being the creator, so the universe, the “all” that everyone said god created, cannot have any other either, and thus could have no.... UH OH! They had to stop the talk. They adjourned the discussion to FAITH as the absolute limit of the necessary use of reason, a gift from god not to be despised nor unused, and left reason right there as able to go no further. They were at least honest as well as religious monks.