Problem of evil
Suppose we have the following four premises:
We get the following contradiction. If God is omnibenevolent, then he does not want evil to exist. If God is omniscient, then he must know about all evil in the world. If God is omnipotent, then he must be capable of doing something about it. Therefore, evil should not exist. Dropping any one of those four premises would resolve the contradiction, but dropping #4 would require us to fundamentally redefine evil in some way, and dropping the other three would undermine the Christian concept of God.
"Is He willing to prevent evil, but not able? Then He is impotent. Is He able, but not willing? Then He is malevolent. Is He both able and willing? Whence then is evil?"
- — Dialogues Concerning Natural Religion
"So how do theists respond to arguments like this? [The Argument from Evil] They say there is a reason for evil, but it is a mystery. Well, let me tell you this: I'm actually one hundred feet tall even though I only appear to be six feet tall. You ask me for proof of this. I have a simple answer: it's a mystery. Just accept my word for it on faith. And that's just the logic theists use in their discussions of evil." [Quentin Smith, "Two Ways to Defend Atheism"]
A theodicy is a proposed solution to the problem of evil. Coined by Gottfried Leibniz in 1710, in a work called "Theodicy Essay on the Benevolence of God, the Free will of man, and the Origin of Evil".
A theodicy can generally be divided into four categories, each typically rejecting one of the four premises used to make the argument. The argument is, after all, not an argument for the non-existence of God but an argument for the non-existence of God with the characteristics of omniscience, omnipotence, and omnibenevolence in the presence of evil. Some arguments aren't solutions to the problem but justifications.
When compared to an easily prevented, extremely "evil" act, such as the rape and murder of a child, or a gross atrocity like the holocaust, slavery or other genocides, most theodicies crumble, quickly exposing them as sophistry with worse implications than the original problem.
God is not omnipotent
It is often claimed that evil exists because God gave humans free will. According to the Bible, God's gift of free will led to the fall of Adam and Eve through their original sin. Free will is assumed to be a greater good than the evil that it causes or is needed by God to serve some purpose. For example, free will is required for people to love God in a free and open fashion. So if a young girl is raped and murdered, this is because God needed the rapist's free will so that his actions could result in greater good or so that the rapist could freely love God.
As Mackie asked: "Why could [God] not have made men such that they always freely choose the good?" Even if man is believed to have free will, God could have created humans such that they would always freely choose the good. This he did not do and is therefore ultimately responsible and blameworthy for any evil act which humans perform.
"For at least some theists, this difficulty is made even more acute by some of their further beliefs: I mean those who envisage a happier or more perfect state of affairs than now exists, whether they look forward to the kingdom of God on earth, or confine their optimism to the expectation of heaven. In either case they are explicitly recognizing the possibility of a state of affairs in which created beings always freely choose the good. If such a state of affairs is coherent enough to be the object of a reasonable hope or faith, it is hard to explain why it does not obtain already."
This argument fails in that free will is given a definition which relies on the ability to perform actions. The implication is that humans must be free to commit actions which would qualify as "evil" as well as "good" in the argument, in order to have free will. In this case, all humans born without this capability, possess no free will. Also, those who have an advantage, of strength, size, or skill, are presumably, more free in their will, in comparison to their potentially smaller, weaker, or less skilled, victims. Therefore, this objection to the problem of evil can only apply where this standard for free will is actually applied. Paradoxically, this puts God in the position of denying free will to someone regardless of God's position on an action, whether God intervenes, or not.
This argument also fails to explain why God allows natural disasters, such as hurricanes, tsunamis, and earthquakes. These events kill large numbers of people in specific geographical locations, which indicates that the concept of "evil" is not necessarily tied to what people do. Furthermore, it fails to account for evil done to people against their will. The argument of free will is used to justify why an infant can be killed, however the infant invoked no measure of free will to allow for this evil to result. So in order to give the gift of free will to this infant, the child is murdered without having any choice in the matter.
Even if we define natural disasters as not being evil, there remains the fact that they occur, and that God does not prevent them or the deaths and suffering they cause. If we replace "evil" with "suffering" in the discussion above, the problem remains: either God is unaware of people's suffering, and is therefore not omniscient; or he is unable to do anything, and is therefore not omnipotent; or he is unwilling to intervene, and is therefore not omnibenevolent.
There is also the question of heaven. Heaven, being a perfectly wonderful place, does not contain evil. Does this mean that inhabitants of heaven no longer retain their free will? Or does their will suddenly become perfectly good?
Bertrand Russell notes: "[I]t is clear that the fundamental doctrines of Christianity demand a great deal of ethical perversion before they can be accepted. The world, we are told, was created by a God who is both good and omnipotent. Before He created the world He foresaw all the pain and misery that it would contain; He is therefore responsible for all of it. It is useless to argue that the pain in the world is due to sin. In the first place, this is not true; it is not sin that causes rivers to overflow their banks or volcanoes to erupt. But even if it were true, it would make no difference. If I were going to beget a child knowing that the child was going to be a homicidal maniac, I should be responsible for his crimes. If God knew in advance the sins of which man would be guilty, He was clearly responsible for all the consequences of those sins when He decided to create man."
See also: The Free Will Defense Refuted and God's Existence Disproved 
A Sound Logical Argument from Evil A Sound Logical Argument of Evil by Quentin Smith
Quentin Smith distinguishes three kinds of freedom:
1. External freedom:A person is externally free with respect to an action A if and only if nothing other than (external to) herself determines either that she perform A or refrain from performing A.
2. Internal freedom: And a person is free with respect to an action A at a time t only if no causal laws and antecedent conditions determine either that he performs A at t or that he refrains from so doing. A person is internally free with respect to an action A if and only if it is false that his past physical and psychological states, in conjunction with causal laws, determine either that he perform A or refrain from performing A.
3. Logical freedom: A person is logically free with respect to an action A if and only if there is some possible world in which he performs A and there is another possible world in which he does not perform A. A person is logically free with respect to a wholly good life (a life in which every morally relevant action performed by the person is a good action) if and only if there is some possible world in which he lives this life and another possible world in which he does not.
These distinctions, according to Smith, constitute a sound logical argument from evil. It is possible to be internally-externally free but logically determined with respect to being morally good. This is the case with God, who is both internally and externally free but who does only good actions in each possible world in which he exists.
1. God possesses the maximally valuable consistent conjunction of great making properties.
2. If it were intrinsically better to be logically free with respect to a morally good life than logically determined, and this logical freedom were consistent with God's omnipotence and omniscience, then God would possess this logical freedom.
3. Logical freedom with respect to a morally good life is consistent with omnipotence and omniscience.
4. God is logically determined with respect to a morally good life.
5. It is false that it is intrinsically better to be logically free with respect to a morally good life than logically determined.
Premise (3) is true because "x knows all truths" does not entail "It is not logically possible for x to perform a morally wrong action," and "x is all-powerful" does not entail "It is not logically possible for x to perform a morally wrong action." Nor does the conjunction of omniscience and omnipotence entail this.
It follows that a possible world WI containing N number of persons who always do what is right and who are logically determined with respect to moral goodness is (all other things being equal) a more metaphysically valuable world than a world W2 containing N number of persons who are logically free with respect to a morally good way of life. And this suggests that God, if he existed, would have created W1 rather than W2.
Although Plantinga does not address this issue, an unspoken assumption of his argument is that there are no possible creatures who are internally-externally free with respect to a morally good life but logically determined. This assumption is false, for "x is an internally-externally free creature with respect to a morally good life" does not entail "x is logically free with respect to a morally good life." If it did, there would have to be some relevant difference between God and creatures that ensured the entailment goes through in the case of creatures but not God. But what could this difference be? None of the divine attributes (other than necessary goodness) entails necessary goodness. Nor does a conjunction of two or more of these divine attributes entail it. Further, the relevant nondivine attributes do not entail logical freedom with respect to a morally good life. For example, "x knows many but not all truths" does not entail "x freely chooses to do something wrong in at least one possible world in which x exists." Nor is this entailed by "x has the power to do many but not all things." a nonomniscient person can have only true moral beliefs, if only for the reason that it is possible to know all moral truths and not know all mathematical truths. Such a person would be necessarily morally good.
6. It is possible that there is a nonomniscient mind x such that: for each possible world W in which x exists, and for each circumstance in which x is faced with a moral choice, x knows all the factual and moral truths he needs to know to make a correct choice.
7. This mind x is neither causally determined nor causally influenced by any external or internal factors.
8. Necessarily, if a perfectly free mind knows all the moral and factual truths needed to make the morally correct choice in any morally significant circum stance in which he finds himself, then this mind will make the correct choice.
If such persons are possible, worlds containing only such persons and God and no nature (a physical realm) are possible; in these worlds, there is no moral or natural evil. The counterfactual argument that it is possible that if God created these persons in certain circumstances, they would do something wrong, fails because these persons are necessarily good. Accordingly, Plantinga's free will defense cannot be used to show that a world containing these persons is not creatable.
The idea that there are possible creatures who are necessarily good and that God could have created a world containing only them does not depend on the truth of Plantinga's theory of counterfactuals of freedom. At first glance, it might appear there is a dependency because presumably God, if he existed, would have known logically prior to creation counterfactuals about these creatures and made his decision to create a world with them on the basis of this knowledge. For example, God would know prior to creation:
9. If the individual essences of some necessarily good creatures were to be instantiated, the instantiations of these essences would always do what is right.
Proposition (9) is true logically prior to creation even if Plantinga's theory is false, for (9) is analytically true and thereby does not require similarity relations among worlds to make it true. Proposition (9) is true because the antecedent entails the consequent. Accordingly, if the Stalnaker-Lewis theory of counterfactuals is true, there are no logically contingent counterfactuals of freedom that are true logically prior to creation, but there are logically necessary counterfactuals of freedom that are true logically prior to creation, and the latter are all that God needs to know which world to create.
The fact that necessarily good creatures are possible supplies the missing proposition (p') that will enable the conjunction of (G), (E), and (p') to form an explicit contradiction.
Statements (G) and (E) we recall, are
G. God exists and is wholly good, omnipotent, and omniscient.
E. There is evil.
There are several ways to formulate (p'), one being based on a proposition in Plantinga's first discussion of the free will defense in his article "The Free Will Defence".
10. If God is all-good and the proposition God creates free humans and the free humans He creates always do what is right is consistent, then any free humans created by God always do what is right.
If the negation of (E) is to be deduced from (10) and (G), then (10) needs to be a necessary truth. But we need further premises. One is
11. It is consistent that God creates free humans and the free humans he creates always do what is right.
12. It is possible that: free humans who always do what is right exist without there being any natural evil, and if God creates these humans, he will not create natural evil.
If (10), (11), and (12) are all necessary truths, then the proposition (p') is the conjunction of ( 10), ( II), and ( 12 ) because the conjunction of these three propositions with (G) entails
-E. There is no evil.
This would give a sound logical argument from evil, for it would show that the theist is committed to a proposition two of whose conjunctions are there is evil and there is no evil.
In "The Free Will Defence" Plantinga attacks (10). He writes, "There seems to be no reason for supposing that (10) is true at all, let alone necessarily true. Whether the free men created by God would always do what is right would presumably be up to them; for all we know they might sometimes exercise their freedom to do what is wrong."
In one sense Plantinga is right, for humans are logically free with respect to a morally good life and being logically free and being logically determined are plausibly thought to be essential properties. There is no possible world in which humans are logically determined with respect to a morally good life. But Plantinga over- looks the possibility that there are possible rational creatures who are internally- externally free but logically determined, and if we take "humans" in (10) in a broad sense as referring to any rational creature, then Plantinga's purported refutation of (10) fails. Thus, the logical argument from evil goes through unscathed by Plantinga's criticism.
The soundness of the logical argument from evil can be seen more clearly if we consider a relevant proposition from Plantinga's God, Freedom and Evil, a proposition that he concedes "for purposes of argument" is a necessary truth (although he subsequently makes no attempt to show it is not a necessary truth). The proposition is
13. An omniscient and omnipotent [and wholly] good being eliminates every evil that it can properly eliminate.
A being properly eliminates an evil state of affairs if it eliminates that evil without either eliminating an outweighing good or bringing about a greater evil. A good state of affairs g outweighs an evil state of affairs e if the conjunctive state of affairs 9 and e is a good state of affairs. Given these definitions, it is plausible to think that (13) is a necessary truth. If a state of affairs is eliminated by its actualization being prevented, and if a possible world is a state of affairs (a maximal state of affairs), then (13) entails
14. God prevents from being actual any world W1 that contains evil if there is another creatable world W2 containing at least as much good as W1 and no evil.
There is no world containing evil that contains more good than a creatable world W2 that contains no evil and that consists of God and an infinite number of necessarily good and internally-externally free rational creatures who perform an infinite number of good acts. This is true by virtue of the mathematics of infinity, for the addition of more creatures or acts to a world containing an infinite number of them does not increase the amount of good, for infinity plus N for any finite number N equals infinity. Thus we cannot say that there is a possible world containing evil and infinity-plus-N good acts and that this world contains more good than a world containing an infinite number of good acts and no evil. Of course, we can get more good acts if we add to a world with aleph-zero good acts an additional aleph-one acts, where aleph-zero is the number of all finite integers and aleph-one is (by the continuum hypothesis) the number of all real numbers. But this sort of argument can be blocked by supporting there is another world with no evil but with aleph-one good acts. The same holds for any other transfinite cardinal greater than aleph-zero.
The above arguments about necessarily good free rational creatures show that
There is some possible creatable world W2 containing only God and an infinite number of necessarily good free rational creatures who perform an infinite number of good acts.
This gives us our explicit contradiction, namely, the conjunction of the following propositions:
G. God exists and is wholly good, omnipotent, and omniscient.
E. There is evil.
14. God prevents from being actual any world W1 that contains evil if there is another creatable world W2 containing at least as much good as W1 and no evil.
15. For any possible creatable world W I containing evil and an infinite number of free rational creatures who perform an infinite number of good acts, there is another possible creatable world W2 containing no evil and an infinite number of necessarily good free rational creatures who perform an infinite number of good acts.
-E. There is no evil (from G, (14], and (15]).
Does free will exist
Against all this is that psychologists are sceptical whether free will exists at all. What moral choices we make depends partly on our culture, on our upbringing, on our genes, even on the state of our brains since some types of brain damage affect our moral decisions and our capacity to lead a morally good life. Brainwashing also restricts any free will that might exist and apparently to God the freedom of those who do brainwashing matters more than the freedom of the victims.
- On the one hand God cares a great deal about free will so that allowing extreme suffering is better than limiting free choice.
- On the other hand God cares relatively little about free will and is unwilling to prevent the restrictions on free choices that exist.
The above is in strict logic possible but intuitively implausible and improbable.
Best of all possible worldsApologists such as Alvin Plantinga have made the claim that although there may be some evil in the world, this is in fact the best of all possible worlds.
This theodicy suggests that no improvement may be made to the world. Preventing children from dying in a tsunami or the Holocaust from happening would be impossible for God. Plantinga argues that God's power is limited in that he cannot sin and cannot violate free will. However, there are plenty of improvements one could make to this world without violating free will or requiring God to sin.
Although it is not a direct problem with the claim itself, it is important to note that many theists who propose this claim also believe in Heaven, which is believed to be an even better world than this one. If this is the best world able to be created then Heaven cannot be created.
See also: The Free Will Defense Refuted and God's Existence Disproved 
Apologists often claim that what appears to be harmful to humans may, in fact, be for humanity's good. How can we learn, the argument goes, without making our own mistakes?
The "tough love" argument only works if God is limited in power. If God is omnipotent there is nothing he can not teach us gently that he can teach us harshly. If he is benevolent than he would never choose to teach us a harsh lesson when it could be taught, with exactly the same impact, gently.
Another problem with this argument is that although according to this argument, God wants us to grow as people by learning from our mistakes, according to most religious doctrine he also wants worship. Worship involves complete obedience and submission, whereas learning from mistakes requires using one's intelligence. It is contradictory to claim that God wants us to be both completely obedient and make decisions for ourselves, since complete obedience means blindly obeying authority, for example the story of Abraham and Issac (Genesis 22:1-19 ). Abraham was called "righteous" because he blindly obeyed God's command to murder his son. The fact that God stopped Abraham before the knife fell means nothing- even if he had allowed the murder, Abraham would still be called righteous for obeying God's command.
Really powerful, not all-powerful
God is not all-powerful in the sense that he can create a rock so heavy that even he cannot lift it. So, God is omnibenevolent, omniscient, and really really powerful.
If a child is raped and killed, is this because God is not powerful enough to prevent it? I could prevent that and would strive to with the smallest degree of foreknowledge. So if this argument is to succeed it must conclude that I am more powerful than God. And more benevolent.
God does not exist
God is unable to prevent evil because God does not exist. Argument does not apply to non-existing gods.
God is not omnibenevolent
One way to redefine the term 'benevolence' is to cite limited human perspective in space and time. A parent might spank a child for running into traffic, or take a child to the doctor for painful, life saving, injections. It is only in the limited, child's-eye-view that these things are malevolent.
As with the "tough love" argument, this view of God implicitly denies his omnipotence or, at least, his omniscience. What kind of parent purposely takes his child for a surgery which he knows the child does not need or want?
Another way to redefine 'benevolence' is to argue that God may be benevolent to specific humans or to non-humans. Our entire history may exist for the positive influence it may have on aliens we have not met. We may be actors in a puppet show that makes these beings happy. After all, it is perfectly possible for benevolent humans to play comically violent video games with their delighted children.
But this argument is sophistry. To win the argument the apologist defines a God that neither we nor he would have much reason to worship. For example, if the creatures in a violent "Run and Gun" video game were to gain self awareness, would we expect them to view us as benevolent beings worthy of their love and trust as we blast them into electronic oblivion?
And, if God is not benevolent toward humans, then what differentiates him from a human sociopath or from the Devil?
The problem of evil must be taken up in the context of humanity. No other context would make a God useful to humans in any realistic way. A God that is benevolent to others at lethal expense to humans is, by definition, malevolent, or at least indifferent, toward humans. It is an unusual apologist indeed who believes in this type of God.
God is benevolent to the point of impotence
Some claim that since God is omnibenevolent, he loves all his creatures, even Satan, who is considered by many to be the embodiment of evil. Therefore it would violate his omnibenevolence to simply destroy Satan or any other evil creation. This of course implies that God is not omnipotent. It is also contradicted by the Bible, which states that God hates evil.
Evil is a consequence of disobeying God
Evil exists not because it was created by God but because it results from our disobeying God's divine laws.
This explanation argues that God has created an earthly consequence for disobeying divine laws. There are two problems with this argument: 1. Innocents being victims of evil. 2. Immoral people escaping earthly consequence. If this argument was indeed true, infants, children, and otherwise good people would not suffer and murderers, thieves, and the like would not live comfortable lives.
Perfection implies no lacking
God is also evil. The argument does not apply.
God allows evil so that the good is appreciated
God wants to be loved and is very vain. He wants to be loved so much that he allows many evils to befall mankind so that they appreciate the good more. Much as the blind man healed by Jesus appreciated his sight more because of his blindness.
God has reasons for allowing/causing temporary suffering/evil
How would one tell the difference between a good god who allows and/or causes evil/suffering without explaining why, and an evil, or indifferent, god?
God is not omniscient
Unlike the other characteristics of God, omniscience isn't necessarily required for the argument. Any situation God doesn't see can still be created as intended through the power of omnipotence.
God does Good. Satan does Evil.
God only has limited omniscience, he cannot see the future. God simply did not know that Satan would turn against him because he cannot know the future. Satan blindsided God, who lacks future knowledge, and created evil himself. God was betrayed and Satan is the reason evil exists.
If God is all-good and all-powerful, he should snuff out Satan and promptly remove all evil from the world.
Evil does not exist
As with "benevolence", "evil" can be redefined. What is "evil" for humans may not be evil for God. In fact, anything that God chooses to do can be construed as "good". Using this argument, "evil" can not exist in any definable terms when applied to God.
Besides the arguments already used in the "Tough Love" response (an all powerful God would have no reason even to appear evil) here, the apologist treads dangerously close to moral relativism. We know from information in the bible that moral rules have changed at the will of God. Is God, then, a moral relativist?
If the answer is that God is following a moral plan, then the apologist opens himself up to the Euthyphro dilemma. If the answer is that God changes as he sees fit and anything that god declares as good is good, then what is the difference between being a relativist and following a relativist God?
When an apologist tries to redefine the premises of "the problem of evil" he finds himself in a morass of relativism, but when he tries to work with the premises he finds himself unwittingly limiting the unlimited God of his religion.
Evil is an illusion
We believe that evil exists because we view things like genocide as bad. We are simply wrong, all of these things are good.
Which suggests that everything which has ever happened is objectively good: rape, the holocaust, slavery, genocide. In order defend this theodicy, a proponent would need to agree that any horrific thing you could mention is a good thing to do.
It is all part of the plan
God's divine plan is good. What we think is evil is not, rather it's a part of God's plan we are misidentifying as evil because we cannot see the big picture.
The holocaust is part of God's divine plan? Young girls being raped and murdered is part of God's plan? If such things are part of God's plan, even without seeing the big picture one must conclude that it's a really bad plan. Furthermore, what is the point of a plan if one is all powerful? There are no steps needed; simply create the end results.
Evil is a test
Evil is needed so that God can test people.
The holocaust is a test of faith? Whose faith is tested when a child is murdered? If God is omniscient, then God already knows what humans will do in any test, rendering the exercise (and the pain caused by evil) pointless and unnecessary.
Evil is the absence of Good
Just as cold is the absence of hot and dark is the absence of light, evil is the absence of good.
This contradicts an omnipresent deity. Furthermore, if accurate then an omnipotent omnibenevolent deity should employ his omnipotence to be omnipresent in order to stand vigilant against evil.
Are evil deeds an absence of some corresponding good? Is rape an absence of unrape? Is murder an absence of unmurder? (How many people have you unraped or unmurdered today? We're committing unsins constantly!) Conversely, if baking your neighbor cookies [or name any random act of kindness] is a good deed, what is the absence of that good deed?
You bring evil on yourself
God is good and does good, but any evil you do you brought upon yourself. This principle is the theodicy of Islam.
If you are raped, you were bad. If you have a holocaust happen to you, you were bad. If something bad happens to you, you brought it on yourself. This theodicy consists of blaming the victim, in the case of a baby born sick or disabled it blames the parents.
Heaven exists after this world
After you die you can go to heaven which evens everything out in the end. Regardless of what pain and suffering exists here, heaven will balance out the scales. This was often used by religious authorities to justify torture and murder during the many inquisitions and crusades. The victims' temporary agony was justified if it saved them from the eternal agony of hell.
This has nothing to do with the argument, rather it's a conclusion that it doesn't matter if there is evil, rather than address the logical consequence of a deity incompatible with an evil filled world.
Another refutation of theodicies:
The Moral Argument from Evil is expounded by Dean Stretton in his article on the subject. Here is the full formulation as given by Stretton:
A1. The most rational theists know (i.e., have a justified, true belief) that God exists.
A2a. For any possible world W, if God exists in W, then every instance of evil in W is objectively justified.
A2b. If God exists, then there is objective justification for any actual instance of evil, including those evils for which there is a human onlooker
A2. If God exists, then there is objective justification for every actual instance of evil, justification that will occur even if no onlooker intervenes to stop or prevent that evil.
A3. Some members of the class of most rational theists (as I have defined that class) are theists who know A2.
A4. Some of the most rational theists (namely, those who know A2) know that there is objective justification for any actual instance of evil, justification that will occur even if no onlooker intervenes to stop or prevent that evil.
A5. If human person P knows that there is objective justification for evil E, and that this justification will occur even if P does not intervene to stop or prevent E, then P is morally justified in allowing E to occur.
A6. Some of the most rational theists (namely, those who know A2) are morally justified in allowing any actual evil to occur.
A7. If the most rational theists know that God exists, then some of those theists (namely, those who know A2) are morally justified in allowing any evil to occur.
A8. Even the most rational theists (including those who know A2) are not morally justified in allowing just any evil to occur.
A9. Even the most rational theists do not know that God exists.
A10. If the most rational theists do not know that God exists, then no theist knows that God exists.
A11. No theist knows that God exists.
A12. For any given theist, that theist’s belief that God exists is either false or unjustified.
A13. If God exists, then some theists are justified in believing that God exists.
A14. If God exists, then no theist has a false belief that God exists.
A15. If God exists, then some theists know (i.e., have a justified, true belief) that God exists.
A16. It is not the case that some theists know (i.e., have a justified and true belief) that God exists.
A17. God does not exist.
This argument can be summarized as follows:
A1 to A2 – If God exists, then all instances of evil are morally justifiable by definition.
A3 to A7 – If all events are morally justifiable, then some believers know that they should not try to stop any instance of presumed evil.
A8 – Yet they do intervene.
A9 to A17 – Therefore their own behaviour proves that God does not exist.
One could argue that the argument above does not cover all possibilities, much like C.S. Lewis's trilemma "Liar, Lunatic or Lord", which does not consider alternate possibilities like "Legend". The argument does not account for a God who is not able and willing, which creates the problem, as paraphrased by Epicurus, that if he is not able or willing, then why call him God?
However, the problem of evil can be restated as follows:
- If evil exists, and God is omniscient, then God knows about it.
- If God knows about evil, and is omnibenevolent, then he wants to prevent it.
- If God wants to prevent evil, and is omnipotent, then he can prevent it (if God wants something to happen, then it happens).
- Therefore, if God is omniscient, omnibenevolent, and omnipotent, then evil should not exist.
There is a logical rebuttal to this version of the problem of evil posited by Alvin Plantinga, a prominent philosopher, called the Free will defense. This defense is widely regarded as solid by the philosophical community, even with some mentionable critisisms.
The problem of good
It is fairly easy to flip the argument around: if we postulate that God is all-evil, the problem of evil becomes the problem of good: why would an infinitely evil god allow good to exist?
Many or all of the arguments against the problem of evil can easily be turned around to argue against the problem of good:
- People do good deeds because God gave us free will, which in turn allows us to torment each other in ways that mere automata couldn't.
- Natural beauty, such as sunsets or the majesty of a starry sky, exists so that we may more deeply appreciate the ugliness around us.
- Mystery: while some instances of good may remain unexplained, who can claim to understand the mind of an infinitely evil god?
If the existence of evil in the universe that also includes a lot of good does not point to an infinitely evil god, then it follows that the existence of good in a universe that also includes a lot of evil does not point to the existence of an infinitely good god.
- Stanford Encyclopedia of Philosophy, The Problem of Evil
- Hume and the Evidential Problem of Evil
- Stephen Law, The God of Eth — the problem of good
- Dictionary.com entry for sophistry