S5

It was defended by John Duns Scotus.

That's recently been defended in the 20th and 21st centuries because of developments in modal logic, especially a system of modal logic called S5 that holds that if something necessary is possible, then what's possibly necessary is necessarily necessary.

okay um modal logic and so if god's exists if god is a necessary being and his existence is possible then god's existence is necessary

right

because what's possible for a necessary being is necessary for a necessary being

right so you you you don't if you want to refute that you have to say not just that uh it's possible that god doesn't exist but it's actually impossible for god to exist And therefore the bar for someone who's a skeptic is raised that much higher if we accept S5 modal logic.

Yeah.

And the big defender of that recently has been Brian Lefto at Oxford.