Sometimes I imagine a debate over whether God created the heavens and the earth.
The negative side says, "God could not have create the heavens and the earth, because God doesn't exist
The positive side says, "Yes, we agree that God doesn't exist, but I believe that God still created the heavens and the earth."
This seems quite ridiculous. Things that don't exist don't create the heavens and the earth.
But at least we can debate whether God exists to create the heavens and the earth. We know that non-existence never exists. Non-being is a lack of existence and therefore a lack of existence of power to cause to be. So when the debate becomes over something else, like whether God exists, the possibility that we came from nothing should be excluded, for the same reason the possibility that the non-existent God created the heavens and the earth should be excluded.