Problem of Hell
Like the problem of evil, the Problem of Hell points out the contradiction in a supposedly just God who sends people to an eternal Hell to be punished for their transgressions. Religious believers differ over what actions warrant an eternal sentence in Hell, but the idea that not believing in a particular God is sufficient for you to deserve this punishment is common. The justice of this doctrine can be questioned by asking whether or not the punishment is proportional to the crime, as illustrated in the following example:
- The Christian god is a loving, just creator.
- Refusing to accept Jesus' gift of salvation renders an eternity of torment.
This central Christian doctrine leaves skeptics with a slew of objections. Why does God judge belief? Beliefs have little impact upon the world relative to the physical actions they inspire. We even realize this in our courts. A just being would punish wrongdoings and let the criminal go after accounting for their actions. Why would God trust finite beings with their infinite future? We would not allow a child to sign a legal document or make investments bound to affect the rest of their life, and yet God allows his creation complete control of their eternal soul! This objection is especially pertinent given the number of religions that make similar claims on the individual's soul. Since no faith appears to have stronger supporting evidence than any of the others, how is it just to punish an individual for making a good-faith effort to follow a different creed and/or philosophy?
Religion has actually convinced people that there's an invisible man living in the sky who watches everything you do, every minute of every day. And the invisible man has a special list of ten things he does not want you to do. And if you do any of these ten things, he has a special place, full of fire and smoke and burning and torture and anguish, where he will send you to live and suffer and burn and choke and scream and cry forever and ever 'til the end of time!
But He loves you.
- — George Carlin 
A related problem is "Why does God allow Satan to continue to exist?"
Other perspectives on the problem
- "It would be absurd to suppose that God inflicts eternal punishment on his creates, which would render their non-existence infinitely preferable to their existence on the whole. "
"The existence of a world without God seems to me less absurd than the presence of a God, existing in all of his perfection, creating imperfect man in order to make him run the risk of Hell."
- — Armand Salacrou
"Must crimes be punished but by other crimes, And greater criminals?"
- — Byron's Manfred
Infinite God, infinite sins
Some theologians have argued that since crime committed against a finite being leads to a finite punishment, sin against an infinite god has infinite consequences. The problem is that we judge the severity of a crime based on the harm inflicted on the victim, not its lifespan. If God is omnipotent, by definition he can't be harmed. He is therefore punishing his creation for deeds that had absolutely no effect on himself. Furthermore, this objection falls short in failing to discriminate between different degrees of transgression. The real-life justice system gives out different punishments to offenders based on the severity of the crimes they committed. Under this standard of justice, there is only one crime--rejecting the word of God--and one punishment--eternal damnation in Hell. Given the indiscriminate nature of this punishment, one might question its desirability as a standard of justice. However we can concede that, despite the despicable nature of a system that issues punishment based not on the severity of the offense but rather on the size of the offended, this fact alone does not prove that hell does not exist. Such a system would speak volumes about the grotesquely evil nature of the being who designed it, but would say nothing about its feasibility; none-the-less, if we take this notion seriously we find largely incompatible with most notions of salvation or post-life reward and punishment. For if we accept that a sin of any variety (from petty theft of an apple to the rape and murder of an entire nation) is offensive to an infinite god; and that an offended infinite being is infinitely offended by virtue of it's infinite nature; and that the person responsible for this offense is therefore deserving of an infinite punishment, then the converse must be true as well. By this infinite standard, any act which pleases god (according to the major theistic faiths this could range from a minor act of worship to the burning of an entire heard of cattle in ritual sacrifice) must bring it infinite pleasure and thus the person responsible is deserving of an infinite reward as a consequence. If this is true, then ultimately salvation can be earned by a single minor act of worship in much the same manner as a single minor offense can make one deserving of eternal damnation. It should be evident that any being capable of designing such a system of reward and punishment could not be characterized as either sane or as remotely concerned with fairness and justice. In all likelihood, if there were a being with the ability to design and create our universe, it would posses a level of sanity that wouldn't allow for the inclusion of a realm of eternal torture.
By ignoring God, humans choose hell
Theists have suggested that by ignoring God or rejecting the atonement, humans also reject all prospects of a pleasant afterlife: God would not want to be with humans who denied him, and he wouldn't force them to be with him. On an infinite time scale, this is also morally unsound because the judging god is still giving thoughts and beliefs priority over physical actions. Religious belief is not a choice. If it were a choice, most skeptics would prefer a continued existence with a god not believed in to eternal torment or eternal death.
A related argument is that people who reject God go to hell, where they continue to reject God and the punishment continues forever. This rashly supposes that no one in hell has ever changed their mind!
- "Insofar as the inhabitants of hell continue to hate God and reject Him, they continue to sin and so accrue to themselves more guilt and more punishment. In a real sense, then, hell is self-perpetuating. "
Moral actions require belief
Other Christians believe that God judges humans by their glorification of him and his will, based on their adherence to his message as described in the Gospels. They believe that the only way to have the moral resume required to get into heaven is by believing in and accepting God. Like the other counter-arguments, this response forgets about the infinite time scale attached to it. It also implies belief in God to be the single most important moral action. The biblical God's omnibenevolence can still be questioned on the grounds that he prefers belief-inspired actions to regular good actions with infinite consequences.
The existence of hell is necessary for the existence of heaven
By far the cruelest response to the problem of hell. The argument goes something like this.
- P1: A heaven where everyone is eternally happy and no one is excluded would not be possible.
- a) People get used to anything.
- b) People define happiness and pleasure in contrast to lack of happiness and pain.
- P2: Pain or a lack of happiness cannot exist in heaven, even for a moment.
- C1: Heaven can only exist if there is some pain outside of heaven, which can be observed by those within heaven.
- P3: Those who go to heaven stay there forever.
- C2: For all eternity, there must be some people outside of heaven who experience pain.
- P4: The greatest possible happiness can only exist in contrast with the greatest possible pain.
- C3: Some people outside of heaven must experience the greatest possible pain, i.e. the eternal torture called hell.
- P5: God can only produce suffering upon those who deserve it (but that includes every person because everyone sins), so hell must be just.
- P6: Those who go to heaven become morally perfect and must agree with God's moral judgments.
- C4: The infinite pleasure felt by those in heaven is an exultation of God's justice in torturing the damned and his mercy in saving believers.
- P1: A heaven where everyone is eternally happy and no one is excluded would not be possible.
Note that the gist of this argument is not a proof for the existence of heaven or hell. Rather it is an argument claiming that in order for heaven to exist, the people who go there must watch (or at least constantly be aware of) other people being tortured in hell. Otherwise heaven wouldn't be pleasant enough to deserve the name. One can attack the premises in this argument, such as by denying P1.b), and/or by defining a heaven like what C.S. Lewis suggested, which eternally gets better and better so that one never tires of it.
However, perhaps a more powerful argument against this line of reasoning is the incredible sadistic cruelty that it entails. The suggestion is that the most important function of hell is for those in heaven to observe it as if it were a spectacle in the Roman Colosseum. That is, one gets to watch non-believers endure punishments like eternally burning without being able to die, and laugh and think "Well, glad that's not me!" and that is the only way that heaven is prevented from becoming boring. Most people would not want to go to a heaven like that, and they shouldn't!
The suggestion here is that the only way to be eternally happy is to feel a smug sadistic pleasure in being infinitely better and more prosperous than most other people. If that is true, the whole system seems to be built on selfishness, arrogance, and ill-will towards others. In that case, perhaps heaven and hell, as they are traditionally conceived of, should not exist. (That is, being morally repugnant, it would be a crime against all that is good and loving were it to exist.)