No one knows what happens when we die, except those people who have died, and they are dead, unless they have come back to life, which does happen sometime. Still, I wonder if saying one does not 'believe' in heaven or hell is akin to saying one does not believe in gravity, or the existence of subatomic particles. We speculate. It's as silly not to believe in heaven and hell as it is to believe. But it's also absurd to talk about these states as if we know what they are, and if they exist, definitively, unless one has been there.
I can't help thinking we are all hell-bound. For all the times I have forgotten God, hell is where I belong. Salvation is not a guarantee, not something to be counted on. My belief in Jesus Christ as Savior would be severely compromised if there was nothing for us to be saved from. If I believe in Jesus, I believe what he says, including his talk of the the afterlife and the last judgment and the 'wailing and gnashing of teeth.' My Christian faith comes with some conditions, and belief in the afterlife is one of them.
But it is just that--a belief. If someone asks me, 'Is there a heaven? Is there a hell?' I will continue to answer, 'I don't know.' But if someone asks me, 'Do you believe in heaven and hell?' I will continue to answer, 'yes,' because I do. My belief is not proof of existence. Still, I would rather live as if there were a hell than die and find out I was wrong.
So, I try to live as if heaven and hell exist, as if my actions in this life have some consequence beyond this life, as if we are playing for keeps, and every play counts. If this life is all there is, I would cash in my chips now.