What is it with this new ontological wave on the Interwebs? For a mathematical axiom, do you need another axiom that tells us that the first one exists? And so

What is it with this new ontological wave on the Interwebs? For a mathematical axiom, do you need another axiom that tells us that the first one exists? And so forth? How would you prove the existence of the universe? Do we not need a bigger universe that contains ours? And so forth? (Don't mention the big bang, which is a bunch of non-falsifiable formulas.)