Why Does Hell Exist?
Currently there is a good deal of discussion among Christians about the morality of hell: it is said that a good God would not condemn people to an eternity of torture. However that has been the belief of most Christians through most of Christian history. It seems to be supported by the Biblical account. The alternative seems about as bad: that God will force himself on people who do not want him.
Note that it is not necessary to say that God imposes hell as punishment. It may be the automatic (indeed logically unavoidable) consequence of rejecting God. It is not clear that God makes it intentionally unpleasant. It may be the nature of the people who are there, and the fact that they are finally given what they want: freedom from God.
Many criticisms of judgement suggest that it is arrogant to say that Christian ideas are true and others are false. "How can you be so arrogant to believe that Christians will go to heaven and everyone else will go to hell." As we will see below, most Christians don't believe this. However the idea that this is arrogant seems odd. We do not criticize mathematics teachers for saying that 2 + 2 is always 4, and that believing sincerely in 5 is not acceptable.
Either there is a God or there isn't. Either Christ died to save us or he didn't. If he did, it's hard to see how it can be arrogant to say so. If he didn't, then Christians are wrong, but not arrogant.
I would say that ultimately hell is a result of the "hardness" of created reality. Let me try to explain: Christianity believes that the universe has a real existence, and that it is distinct from God. (This is a specific position, which not all religions and philosophies accept. For some, there isn't a real distinction between God and the universe.) In order to provide us with a region in which we can make our own decisions and take our own actions, God set up a universe that operates under dependable laws. Possibly there are other ways he could have worked. But we don't know of any other way to set things up so that we have real lives of our own.
The existence of a real universe with dependable laws has consequences. One of those consequences is the fact that people can have incorrect ideas. If they misunderstand the way the universe works, damage may result. Most of us understand this in the realm of science and engineering. There is no reason that theology should be different. If there weren't any distinction between truth and falsehood, nor any consequences to error, we would be living in an amorphous mess (the metaphysical equivalent of "gray goo"). There would be no way to live sensibly.
The standard Christian position is that salvation is only available through Christ. This isn't because God is biased towards Christians. Rather, it's a consequence of the way the universe works. Heaven is by definition eternal life with God. But Christ is God's way of establishing relationships between human beings and himself. He is the divine logos, the agent of creation. It is inherently impossible to be with God without being in Christ. If a human being somehow managed to be in God's presence bypassing Christ, that person would be unmade.
The only alternatives I can see to hell are for God to arrange for everyone to accept Christ, or for him to destroy everyone who does not. As you'll see below, each of these alternatives has its supporters. However most Christians believe that if everyone ends up choosing God, human existence is a sham: God loaded the dice to such an extent that there were no real human decisions. Most Christians also believe that a part of us is immortal. For God to destroy it would be an interference in the created order that would seriously violate its integrity.
Before judging these issues, I'd ask you to look at some additional considerations.
Is Hell Unfair?
The standard Christian position is that anyone who rejects Christ will end up in hell. Does this mean that only Christians can be saved? The Catholic church and many Protestant churches don't think so. They believe it is possible that Christ can come to someone in an inward and spiritual way, even if they've never heard of Christ. Thus someone can be an "anonymous Christian." That is, they can know Christ spiritually without realizing it it Christ.
Most Christians also believe that God's judgement will take into account the sorts of opportunities a person had to learn the truth. A person who has never heard the Gospel can't be said to have rejected Christ. An even worse situation occurs when Christians have persecuted other groups. A person who sees Christ as a persecutor has hardly had a real exposure to the Gospel.
[Historical note: It's worth noting that two major classical Protestant writers thought it was possible for non-Christians to be saved: Zwingli and Wesley. Calvin did not.]
Alternatives to Hell?
There is a substantial minority view, which says that God will find some way to reach everyone. This is called "universalism". A few 20th Cent thinkers have also suggested that those who are not destined for heaven are simply destroyed. This is called "annihilationism".
Most Christians think that both of these alternative views are ruled out by teachings in the Bible. Jesus himself speaks of judgement, and of "Gehenna" and "the outer darkness".
While most Christians reject universalism and annihilationism as doctrines, many orthodox Christians hold positions that are very close. Let's look at them briefly:
There is no statement in the Bible about how many will be damned. When someone asks Jesus this, he deflects the question. He does say that the way to salvation is narrow, and that many follow the road to destruction. However we can still hope that in the end God will deflect those on the easy road to destruction. I believe universalism as a doctrine is unorthodox, but hope for all is possible.
A number of orthodox 20th Century writers point out that those who are in hell are not the same kind of people as those in heaven. Human beings are designed to live with God. In heaven our humanity is perfected. Hell is not described in any detail in the Bible. The descriptions that most people hear are based on speculative fiction, such as Dante's. However if humanity is created to be with God, then it is reasonable to believe that those who are finally separated from God in hell are less than fully human. Several writers refer to them as equivalent to "ashes", the remnants of what used to be a human life. Thus we may not have two groups of people living next to each other, with the saved watching the damned living in torture. Hell, whatever it is, has less reality than heaven. This is suggested by Jesus' most common way of referring to it. He calls it Gehenna. This was the garbage pit outside of Jerusalem, although the term also was used in discussions of the last judgement.
Could Hitler end up in Heaven?
Heaven and hell are not a matter of totaling up good deeds and bad deeds and seeing which predominates. From the Christian perspective, if it comes to merit, no one merits heaven, and we've all done enough bad for hell to be justified. However God doesn't want anyone to end up in hell. Anyone who depends upon him for rescue will be saved from hell.
There are several questions that are asked so commonly that I think they're work looking at here. Here are two examples:
Could Hitler end up in heaven if he repented at the last minute?
It seems unfair for God to save people just because they are Christians. There are lots of rotten Christians and lots of good non-Christians.
I'm going to try to deal with that whole class of questions here. Note that in doing so I'm going to make my own opinions a bit more obvious than I do elsewhere in these essays. I am quite sure that there are answers from Catholic and Orthodox perspectives, but I'm not in a position to argue convincingly from those viewpoints.
First, the Bible doesn't give us precise information as to who will end up in heaven or hell. We are warned particularly not to judge other people (except to the extent that we have specific responsibilities for church discipline or as officials involved with the legal system). This means that discussing specific people such as Hitler is dangerous. We don't know what is going on with individuals. Hitler looks particularly evil. But someone completely unremarkable may be just as evil, but may not have had enough political power to have the terrible effect that Hitler did. Perhaps Hitler was completely insane, and not responsible for his actions. (I seriously doubt it, but we don't know for sure what was going on in his heart.)
However more important, I need to warn you that heaven isn't a reward for being good. The basic Protestant model for salvation is as follows:
*God chooses us
*We respond with faith, which basically means that we rely on God for salvation
*God forgives us, and simultaneously starts renewing us and getting rid of our sin
There is certainly a connection between faith and being good: Faith is our side of the bond that connects us to God. God will use that connection to regenerate us and get rid of our sin. The process isn't finished in this life, but it certainly is started. Christians should be better than if they weren't Christians. Jesus said that you will know his followers by the fruit that they bear.
It would be nice if we could say that the best half (or whatever) of mankind are Christians and the worst half are non-Christians. Unfortunately, I'm afraid it isn't going to be quite that neat. Some people become Christians late in their life, and so the process has only started when they die. Some Christians may be in more dangerous positions than non-Christians. Some Christians may have been born with really bad tempers, etc, which makes them look more evil than they actually are.
So I'd say that there should be real evidence of regeneration operating in the lives of Christians, but you shouldn't expect that all the people who look good are Christians and all those who look bad are non-Christians.
Here's one thing to think about: What happens to someone who is relatively good in this life, but who does not have faith? Unfortunately, he may end up in hell. In theory this person could be the best person who ever lived (except Jesus, who was without sin).
The problem is that by not having faith, they do not have the connection through which God will take care of their remaining sin. Even though there aren't very many visible problems, they (and the underlying addiction to sin of which they are symptoms) can't be dealt with. Thus this person can't be made fit for heaven.
Now the obvious response to this is: so why shouldn't people just go ahead and be evil, if heaven isn't based on being good? While heaven isn't a reward for reaching a certain quota of good acts, you won't get in unless you have a relationship with God through which you can be renewed. Someone who says "let me be evil for my whole life, and repent at the last minute" almost certainly isn't going to be capable of repenting in any way that does him any good. In having that intention, he has already rejected the kind of faith that is needed for salvation.
Strictly speaking, heaven isn't even a reward for having faith. It's not that God is rewarding you for faith and punishing you for not having faith. Rather, it's that God uses a certain kind of relationship in order to make you fit for heaven. Faith is a key part of that relationship. If you're sloppy about building a bridge it may fall down. Nature isn't consciously punishing you. It's just the way the universe is built. In my view,
one of the spiritual laws of the universe is that in order to end up in heaven, you have to have justifying faith (not just intellectual belief in the Trinity -- justifying faith means that you rely on and commit yourself to God as your savior).
http://geneva.rutgers.edu/src/christianity/heavenhell.html