If the universe has no cause, then it is not necessary for it to exist.
This argument is used in the debate Does God exist?.
This argument is an objection to The universe is contingent.
Summary
Quotes
“But here's the twist: not only is the universe contingent, but "primo" it has no cause, and "secundo" something must necessarily exist (this universe or another). But if the universe has no cause, where does this necessity come from? No law, no principle, no being is available to explain why it's impossible for nothing to exist. If the totality of what is could not exist, then it could really exist nothing, and the existence of anything is contingent. It's impossible to pull a second-order necessity out of the hat and wrap it around the whole, because there's nowhere to take it. So it's one of two things: either the contingency of the universe is real, nothingness is a real possibility and there really could have been nothing at all (if we deny this, then the contingency of the world is just an illusion, or a purely verbal concession); or the contingency of the world is not real, and then the universe is necessary (but in this case, we have to argue such a position, which isn't easy, and besides, Meillassoux is, like us, convinced of the contrary). In our view, it is therefore unjustified for him to simultaneously claim the benefit of both positions.”
