It would be very convenient if we had, at least non-constructively, a correspondent formal system that could reproduce any causal event within the universe.
The strength would be that naturalism would hold just from the mere fact that axioms exist and that deduction is a sequent which can be done cut-free, thus every proven statement would be a subformula of some of the premises.
Thus, naturalism would be a crystal clear conclusion.
Perhaps it is a bit much to ask how to solve Hilberts 6th problem, so to ask differently:
Under what circumstances could reality not be reduced to a formal system?
Could it be that spontaneous indeterminacies that are observed in quantum physics violate the demanded rigidity of such a formal system?
∀x: Mine(x)
]. Done.