The popularity of C. S. Lewis among fundagelicals is a bit puzzling, because he was, relative to them, a liberal. One thing he does for them, though, is give them an orthodox-sounding way to make the doctrine of Hell less odious. Lewis, you see, thought Hell was something people inflict on themselves by rejecting God. But Randal Rauser, a (also relatively liberal) evangelical scholar isn’t satisfied. After explaining the problems in terms of Biblical interpretation, he says:
Now for the philosophical problem. Even if Lewis were correct and the suffering were self-imposed, that wouldn’t remove the moral offense of hell.
Imagine a man so disordered that he continually inflicts suffering on himself. He cuts himself, bangs his head into the wall, hits his hand with a hammer, pulls out his own finger nails with pliers, and worse.
Would anybody say that the rest of us have no moral obligation to put a stop to this man’s self-imposed misery? Of course we would. We would restrain him to prevent him from inflicting further suffering on himself.
Let’s say that he then responded by biting his own tongue off. Though restrained he continued to find new ways to inflict suffering on himself in a singular quest for his own self-destruction.
Eventually we might conclude that the most charitable thing to do in this impossible situation would be to induce a coma. Perhaps that would be the only way to stop his endless spiral of self-imposed misery.
And that’s the problem. Even if the misery of those in hell is purely self-imposed, even if the gates of hell are locked on the inside and God doesn’t actively torture anyone, the moral problem with eternal conscious torment remains. Even if that torment is self-imposed we must ask why an infinitely loving God would ever allow it.
The one thing I’d add is that Lewis thought non-Christians could go to heaven, whereas fundagelicals tend to try to combine his view of what Hell is with the view that everyone who’s not a Christian is going there. This requires thinking that all non-Christians are deciding to reject God, which is pretty implausible.