I'll respond to a statement that a commenter left on my blog:
I'm not sure how to answer the atheist objection that it's special pleading and ad hoc to appeal to God's special prerogatives (as God) to get out of the dilemma that the types of evils God allows/permits (and ordains in the case of Calvinism) would be evil on our part if we allowed or planned them but somehow not evil for God if He allows or plans/ordains them.
I believe that by faith, but I'm not sure how to rationally defend that to an atheist (though, it's much easier against an Arminian who accepts Biblical authority). Especially if I include in the problem of evil the uniquely Calvinistic view of reprobation (and pre-damnation as some Calvinists make a distinction).
The atheist question is "How does appealing to God's superior ontology and status as Creator, the most perfect and supreme being and who is allegedly the standard of goodness exempt Him from being guilty of evil for allowing and ordaining such things when of all beings in existence He's the most capable of preventing them?" It's not merely that God is supposed to be guilty, but especially guilty because God, in His omnipotence, can prevent them from occurring.
And in the case of Calvinism, God doesn't passively permit, but actively ordains evils and reprobation. As I've been asked, "How can Calvinists claim God is good with a straight face?" Allegedly, there's cognitive dissonance involved.
Ryan Hedrich already gave a good response. Now for me:
i) It's true that some Calvinists are too quick to invoke divine authority as a solution. Although that response is true at a certain level, it's not an explanation, and it's only persuasive for someone who already agrees with the theological framework–yet that's the very issue in dispute.
In fairness, I've seen Arminians stipulate that God has a morally sufficient reason for permitting inscrutable evils. But, of course, that appeal has no explanatory value, and begs the question. Likewise, Marilyn McCord Adams contends that divine and human goods are ontologically incommensurate. So these maneuvers are hardly confined to Calvinists.
ii) Suppose you have a fictional character in a story who enjoys foresight regarding the future. To be precise, he foresees two possible futures: what will transpire if he intervenes and what will transpire if he doesn't intervene. He often finds himself in situations where he could prevent some tragedy, yet he refrains from doing so. For instance, he sees a house fire. He's in a position to rescue one of the children who's trapped inside. Yet he does nothing. To outside observers, his inaction appears to be reprehensible.
But here's the dilemma: what if by preventing a short-term evil he causes a long-term evil or preempts a second-order good? Whenever he intervenes, there are tradeoffs. By preventing harm to some people, his action has the side-effect of harming others, or eliminating some resultant good.
What if he knows that the child, had he survived, would have a tenth-generation descendent who's a serial killer? Or what if he knows that if the child dies, the parents will procreate another child to take the place of the child they lost in the house fire. If he intervenes, he deprives the replacement child of existence. So which life takes precedence? On either scenario, someone loses out. Someone will benefit from his action or be harmed by his action. There's no timeline that secures all the same goods while eliminating every evil. In each alternate timeline, some evils are offset by some goods while some goods come at the cost of some evils.
A fallen world is a network of good and evil. Some evils cause some goods. Some goods cause some evils. Some goods preempt other goods.
iii) Or suppose you had a video game with artificially intelligent characters. Should the gamer forestall harm to his characters? Well, that depends. The game has a plot. One thing leads to another. Some characters come into existence as a result of what other characters do, including the actions of villainous characters. You might even have the heroic son of a villainous father. By preventing certain harms to certain characters, the gamer is robbing some potential characters of existence. Likewise, by eliminating all the villains, he eliminates some of the heroes, whose existence is contingent on the prior actions of the bad guys. Some good guys wouldn't exist if some bad guys didn't exist. Suppose a bad guy kills the boyfriend of a female character. As a result, she marries someone else, and has a son by him, who turns out to be a hero. (Or has a daughter who turns out to be a heroine.) In this case, preventing one murder takes another life. So eliminating some evils must be balanced off the resultant goods that you thereby eliminate, or alternative evils that take their place.
iv) The fact that humans are related to other humans, whereas God is inhuman, can in some measure justify differential treatment. To take a few examples, suppose a grown son commits a heinous murder. He is sentenced to death. It would be cruel to require his family to carry out the sentence. It's better to delegate execution to a disinterested third-party.
Likewise, suppose you're given a choice between saving your mother's life and saving the lives of fifty innocent people. Objectively speaking, it could be argued that saving fifty innocent lives is better, or more obligatory, than saving one life. But it would be unbearable for a son to sacrifice his own mother to save fifty strangers. Moreover, it's not even clear that his duty to the common good overrides his filial duty.
There are situations in which in would be right for an angel or an alien from Alpha Centuri to do something which would be wrong for a human to do, precisely because the alien or angel isn't human. He doesn't have the same social obligations or emotional investments where humans are concerned. He can act with greater moral detachment.
v) Finally, everyone who suffers evil is evil in some degree. Take a mob family. Mothers, fathers, aunts, uncles, husbands, wives, siblings, cousins. Some members of the mob family may be much more evil than others. Still, there's a sense in which none of them deserves to be immune from harm. And some of them richly deserved to be harmed.