An Overview of the Problem of Evil


One of the main objections to the belief in the existence of a loving God is the problem of evil. Not just atheist academics are familiar with it. The average person understands that it is difficult to explain why a loving God would allow the quantity and type of suffering that we see.

Classic Statement of the Problem

From David Hume in the 18th century:

“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? When then is evil?” 1

So, borrowing from the atheistic philosopher J. L. Mackie, we might say that the problem of evil is that the following three propositions are accepted by classical theists but are contradictory:

  1. God is omnipotent.
  2. God is wholly good.
  3. Evil exists.2

So how do we respond to that?

Important Groundwork

We need to get a few things straight to understand this.

Can God Do Anything?

One way to think about the problem of evil is that since God can do anything, He could’ve created the world without evil. One response is to say that God can’t do anything. God can do what we consider physically impossible (e.g. traveling faster than the speed of light), but God cannot do the logically impossible (e.g. creating a square circle or creating a triangular polygon that isn’t also a trilateral polygon).

So, as counterintuitive as it might first seem, the theist can say that God is omnipotent but that there are some things that he cannot do.

Formally Stating Arguments

One helpful tool is to formally state an argument. For example, I could say, “Ben doesn’t like socks because he doesn’t like shoes.” But to think through that argument, it is helpful to state it formally:

  1. If someone doesn’t like wearing shoes, then he doesn’t like wearing socks.
  2. Ben doesn’t like wearing shoes.
  3. Therefore, Ben doesn’t like wearing socks.

Arguments like this need two things to be true to work: they need to be logically valid, meaning roughly that if the premises are true, then the conclusion would be true as a consequence of the logical form of the argument.

When we evaluate arguments like this, we can attack it three ways:

  • Reject one or more the premises.
  • Show that it is invalid. (That there’s a problem with the logic.)
  • Show that a rejection of the conclusion is more reasonable than accepting one of the premises. (Really a way of just rejecting a premise.)

Another way to formalize an argument like the logical problem of evil (because it is meant to display a contradiction) is to give a list of propositions that, when taken together, contain an explicit contradiction.

Implicit Versus Explicit Contradictions

The logical problem of evil, as stated above, claims that a contradiction exists between the three premises above. A contradiction can be implicit (hidden by how the statements are phrased), or it can be explicit (laying bare that one part of one of the statements contradicts another part).

An example of an explicit contradiction:

  1. The object is red.
  2. The object is not red.

An example of an implicit contradiction:

  1. The object is red.
  2. The object is not colored.

The only way to see that this implicit contradiction is actually a contradiction is to know that an object being red implies that the object is colored.

Formalizing the Argument

Now, notice two things. First, the classic statement of the problem of evil isn’t formalized. And, second, the supposed contradiction is implicit. So we need to get someone to formalize the logical problem of evil and make the contradiction explicit.

Interestingly, this isn’t as easy as you might think.

How would you try to formalize the argument so that it works and so that the contradiction is apparent?

J. L. Mackie supplies two premises that, when added to the rest, creates this argument:

  1. God exists.
  2. God is omnipotent, perfectly good, and omniscient.
  3. Evil exists.
  4. A perfectly good being would always eliminate evil as far as it could.
  5. There are no limits to what an omnipotent being can do.

We have already seen that there can be logical limits to what God can do. So, as long as we understand it to mean there are no nonlogical limits to what an omnipotent being can do, then we would accept #5. Orthodox Christians accept premises #1-3. (Some Christians deny premise #2 because they would deny that God is all-knowing.)

But even this formulation isn’t contradictory. Do you see why? We need to rewrite #3.

  1. God exists.
  2. God is omnipotent, perfectly good, and omniscient.
  3. There exists evil in the world that God could have eliminated.
  4. A perfectly good being would always eliminate evil as far as it could.
  5. There are no limits to what an omnipotent being can do.

Now, there is a contradiction. How would you respond?

There are two premises that a Christian could challenge: #3 and #5. Let’s look at three ways that a Christian could respond to this argument.

Greater Good: It is morally permissible to allow some evils in order that a greater good can result. For example, ordering men to sacrifice their lives in a war to stop a ruthless invading army is an evil (it’s evil that the men had to die) but the rescue of the women and children in the nearby town was a good that outweighed the evil. So God has allowed evils that leads to a greater good. What greater goods? Faith and reliance on him; growing towards their intended finite perfection (the so-called soul-making theodicy); interdependence on each other; a hope for a world renewed by God. So this is a rejection of #4, because it purports to give a reason that a perfectly good being would choose not to eliminate an evil it could have prevented.

Free Will Defense: God could not create free beings who could not choose the possibility of evil (if he presented them from doing evil, they would not be free.) God judged that creating free beings like humans was a greater good than the evil that would result.

Skeptical Theism: People who believe that God exists but that we are not in an epistemic position to say what God would do. So we cannot say that God would always eliminate evils as far as possible.

Natural Versus Moral Evils

We need to be aware of the distinction between natural evils and moral evils: natural evils are evils that result from the natural order and not from moral agents (droughts, tornadoes, diseases, etc.); moral evils are evils that result from a moral agent (e.g. a murder or the Holocaust).

Natural evils do not occur because human beings have free will. So the free will defense So how would we respond to them? By using the other two responses to the logical problem of evil. First, we could say that greater goods result: our dependence on God, our hope for a redeemed world, our realization of the consequences of living in a world that has fallen as the result of rejecting God, etc. Or we could invoke the skeptical theist route: we don’t know whether God could have created a natural world without the possibility of natural evils, or we could just be skeptical about other reasons God could allow them (maybe they are the result of powerful, non-human, free being (demons) or something like that).

Conclusion to the Logical Problem of Evil

For these reasons, as the atheist philosopher William L. Rowe writes:

“The theist need not be unduly troubled by the logical form of the problem of evil, for…no one has established that [the relevant premises that a classical theist is committed to] are inconsistent.” 3

The Evidential Problem of Evil

Another way to state the problem of evil is what’s known as the evidential problem of evil. This version of the problem of evil doesn’t claim that the existence of evil contradicts the claim that God exists. It claims that existence of gratuitous evil, that is, evil that doesn’t obviously bring about any good, like a fawn suffering in a forest fire, makes it unlikely that God exists. (After all, there is a chance that some acts of evil don’t bring about any good.)

Here’s one way to state it 4:

  1. At least some of the evils in our world appear gratuitous.
  2. Therefore, at least some of the evils in our world are gratuitous.
  3. If God exists, there is no gratuitous evil.
  4. Therefore, God does not exist.

Since it doesn’t claim that evil and God’s existence contradict one another, then it is a tougher argument to refute. It merely claims that the theist’s explanation of the existence of evil is less likely than the likelihood that some evils will not bring about a greater good. It also seems that the more cases of apparently gratuitous suffering we have, the stronger this argument it (because it is more evidence for the conclusion that God doesn’t exist). The more apparently gratuitous suffering that exists, the greater the likelihood that at least one case of apparent gratuitous evil is real gratuitous evil, implying that God doesn’t exist.

(I prefer a probabilistic version of the evidential problem of evil:

  1. At least some of the evils in our world appear gratuitous.
  2. It is probably that some of these apparently gratuitous evils are real gratuitous evils.
  3. If God exists, no gratuitous evil would exist.
  4. Therefore, it is probable that God does not exist).

Responses to the Evidential Problem of Evil

How would you respond?

Here are three responses adapted from William Lane Craig and J. P. Moreland5:

  • God’s existence is probable given all the evidence, including the possibility that some apparently gratuitous evils are really gratuitous evils.
  • We are not in a good position to judge that the probability of premise #2. It could be highly unlikely.
  • Specifically Christian theism has other commitments that increase the probability that God and evils that appear gratuitous co-exist.

We can also respond in two other ways:

Skeptical Theism: The skeptical theist can reject the move from Premise #1 to #2. 6

“Moore’s Shift”: We can say that the existence of God and the incompatibility of God and gratuitous evils gives us reasons to believe that, despite the appearance of gratuitous evils, those evils are actually not gratuitous. In this case, we accept premises 1 and 3 and add to them the premise that God exists (the negation of premise 4), and conclude the negation of #2. So what it comes down to is which premise (“God exists” or “At least some of the evils in our world are gratuitous evils” is more justified.)


So the theist has good reasons to believe that the problem of evil can be satisfactorily answered.

  1. From Hume’s Dialogues Concerning Natural Religion
  2. From Alvin Plantinga’s “The Free Will Defense,” a selection from his God, Freedom, and Evil
  3. William L. Rowe, Philosophy of Religion: An Introduction, 4th ed. (Thomson Wadsworth: Belmont, CA, 2007), 119. 
  4. Justin P. McBrayer, “Skeptical Theism”, Philosophy Compass 5/7(2010), 612. 
  5. William Lane Craig & J. P. Moreland, Philosophical Foundations for a Christian Worldview (IVP Press: Downers Grove, IL, 2003), 541-48 
  6. Justin P. McBrayer, “Skeptical Theism”, Philosophy Compass 5/7(2010), 612. 

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