By far the most common objection raised against Christian theism is the so-called “problem of evil.” If God is all-good, and God is all-powerful, why do suffering and evil exist? Every Christian apologist should be prepared to answer this inevitable question. How you answer this question will depend on a variety of factors, including your apologetic methodology and theological/philosophical commitments. In formulating your response, here are three tips to remember for consistency and effectiveness.
Tip #1: Remember there are various problems of evil and respective solutions.
John Feinberg begins his book The Many Faces of Evil by laying out two very helpful and essential ground rules that must be understood by anyone attempting to discuss God and the problem of evil. The first is that there is no such thing as the problem of evil.
In fact, there are several problems of evil, not just one. What Feinberg means is that the phrase “problem of evil” can be used to refer to a host of different dilemmas arising over the issue of God and evil. For example, this phrase may be referring to the religious/emotional problem of evil, the logical problem of evil, or the evidential problem of evil. A person might be questioning moral evil or natural evil. That there is not just one “problem of evil” means that any discussion about God and evil must first begin by clarifying what problem is under discussion. Each problem is separate and therefore may require its own solution. In addition, the skeptic cannot reject a defense for a particular problem of evil by arguing that it does not solve every problem of evil. No one defense addresses every problem of evil, nor was it intended to do so.
For example, an atheist may reject the free will defense because they don’t believe it adequately handles the problem of natural evil. But the free will defense is primarily used when addressing the problem of moral evil, not natural evil. Solving the problem of natural evil may require additional argumentation or an entirely different solution altogether. Either way, the atheist who reasons this way is simply mistaken. As Feinberg notes, “It is wrongheaded at a very fundamental level to think that because a given defense or theodicy doesn’t solve every problem of evil, it doesn’t solve any problem of evil.”
In summary, remember to identify which problem of evil is under discussion, and don’t expect any solution to answer every problem.
Tip #2: The logical problem of evil is about internal consistency.
The second ground rule laid out by Feinberg is that the problem of evil in its logical form is about the internal consistency of any given theological position. In other words, the skeptic is claiming there is a contradiction in the theist’s system and is therefore obligated to show a specific problem within the system they are attacking. Skeptics must be careful not to artificially generate an internal inconsistency within the theist’s system by attributing views of God, evil, freedom, love, omnipotence, justice, etc., to the theist which the theist himself doesn't hold.
For example, suppose a Christian employs the free will defense in answering the problem of moral evil. An atheist cannot object to the free will defense on grounds that God could create human beings with free will and yet at the same time eliminate all moral evil, assuming a view of free will known as compatibilism. If the theist incorporating the free will defense holds to libertarian free will, the atheist would be artificially (falsely) generating an internal inconsistency by importing his own definition of free will into the theist’s system. The atheist again is simply mistaken. If an internal inconsistency exists, it must be shown to exist within the theist’s system, not one imposed on him by the atheist. A critic may not like a particular defense or theodicy and may object to the system on external grounds, but this has nothing to do with whether the theist’s system suffers from an internal contradiction.
A similar example occurs when an atheist claims that the doctrine of divine omnipotence means that “God can do anything.” This is not what Christians mean when they speak of God’s omnipotence. Omnipotence means God can do whatever is logically possible and consistent with His nature (e.g., God cannot sin or make square circles). This means God cannot actualize a world which contains a contradictory state of affairs, and understanding this becomes important when constructing an answer to a particular problem of evil.
In summary, remember the importance of internal consistency and avoid foreign definitions being imported into your system.
Tip #3: Your answer to the problem of evil needs to be consistent with your theology.
This follows in line with Tip #2. As an apologist answering the problems of evil, whether you present the free will defense, a soul-building theodicy, or other solutions, make sure your answers are consistent with your own theology.
For example, if you hold to Reformed theology and compatibilist free will, you shouldn’t be employing the free will defense, as this position assumes the truth of libertarian free will. This would make your system internally inconsistent since this defense is based on the idea that God cannot actualize a world in which libertarian free creatures always choose the moral good. While the free will defense is extremely popular, not every theological system can employ it consistently.
Remember, many of the supposed contradictions between God and evil simply assume that God does not have a morally sufficient reason for allowing the evil He does. But this is a claim the critic needs to justify. As long as the theist offers a possible explanation as to why God allows evil, the charge of contradiction becomes groundless. Of course, theists should certainly do their best to offer not just possible, but plausible solutions. In fact, there are already many theological systems that are able to solve their own logical problem of evil. These systems include theonomy, Leibnizian Rationalism, as well as those incorporating a free will defense and other “greater good” theodicies.