Now the third post in the third section of theology in bullet points.
Suffering, in itself, is not evil. It is evil when a person wants to cause suffering for no good reason, but the suffering in itself is not evil.
For example, it can be painful to undergo certain types of medical treatments. A doctor might tell a patient, "This is going to hurt a little bit" before doing something that will ultimately help him or her. Good parents let their children struggle sometimes so that they can learn how to live on their own and learn the consequences of certain actions.
Suffering is thus not evil unless there is an evil intention behind it. Even in this case, it is the intention that is more precisely evil rather than the suffering itself.
Pleasure and pain thus do not align precisely with good and evil.  As with evil, it depends on the context and the object of desire.  From a Christian perspective, pleasure is often not good. So the pleasure of eating in itself is good, but the pleasure some get from gluttony is not. The pleasure of sex is good, but the pleasure some get from indiscriminate sex is not.
The problem of suffering is thus not the suffering itself. The question of suffering is the question of why God allows it to take place. Why does God allow people he loves to experience pain?
On one level, the answer to this question is similar to the situation of a parent and child. Children need to do things for themselves so that they can mature and eventually become adults. They need to learn from their mistakes and be redirected when their intentions are evil.
The "problem of evil" is the question of why a good God allows good people to suffer and evil people to prevail. One of the earliest Christian explanations of the problem of suffering and evil (called a "theodicy") was that of the early Christian Irenaeus (late 100s). It is thus called the "Irenaean theodicy." In his explanation, God allows suffering in the world so that we can grow morally. Choices for good make us more virtuous, and we make those choices when we are confronted with challenges. Are we going to take the easy way out? Are we going to harm others to help ourselves?
The muscles of a person who is bedridden for a prolonged period of time will atrophy. "Use it or lose it," the saying goes. In the same way, if we do not face challenges and moral choices in life, it will not be possible for us to mature in character and virtue. It is the way God has created us.
Some suffering also is a result of the choices of others. Augustine (354-430) suggested that the world God created, in which Adam can choose good or evil, is a good world. This is sometimes called the "Augustinian theodicy." A world in which we can freely choose the good is a good world. However, we can also freely choose to do evil in that world as well, and when one person chooses evil, it can lead to the suffering of others.
These theodicies go a long way toward explaining how a God who loves the universe might allow evil and suffering. They suggest that God allows us to make choices for evil because doing so also allows us to make choices for good. The downside is of course that others may experience suffering as a result of our bad choices.
They also suggest that suffering can be a tool of virtue. Indeed, we should probably try not to think of suffering as intrinsically bad. Often, although not always, those who question God in times of suffering were not grateful in those times when they were not suffering. Often, although not always, those who get angry at God in a time of trial are those who took him for granted in their time of blessing.
The alternative, of course, is not some other good being. If there is no God, then suffering has no meaning whatsoever. If there is no God, then we are just another self-interested animal, and our deaths are no more significant in the vast scheme of things than road kill on the side of the road. Those who get angry with God for suffering are getting angry at their only hope for suffering to matter to the universe. If there is no God, then there is no one to get angry at.
Augustine went further in his analysis of evil. It is he who coined the phrase, "the Fall." In his interpretation of the Genesis 3 story, Adam was free not to choose sin (posse non peccare). But after Adam sinned, we are no longer free to choose the good. The creation "fell" when Adam sinned. Now, human beings cannot do any good in their own power. Our "nature" is only to do evil.
But further, for him the world also became enslaved to sin at that time (cf. Rom. 8:20-21). For him, suffering entered the world primarily if not exclusively as a result of Adam's sin. To Augustine, things like disease, earthquakes, and tsunamis entered the world as a result of Adam's sin.
In some ways, this version of the "free will theodicy" makes the existence of evil in the world a little more difficult, because no one today is actually free not to choose evil.  John Wesley's sense of prevenient grace may provide a small antidote. Prevenient grace is the idea that God reaches out to each of us when we are not able to reach out to him. It is the idea that God empowers us to choose good even though we are not capable in our own power. This notion preserves the idea of evil as a choice and thus rehabilitates the potential power of the free will explanation for evil. 
In the end, we will never know the reasons behind every instance of suffering. We know that suffering can be a tool of the good and of virtue. We know that God can bring good out of suffering. We know that some suffering is a result of the evil choices of others, and a world in which we can make evil choices is a world in which we can make good choices, which is good. We know that God sometimes does intervene to stop evil and suffering, and Christians believe that God will return one day to do so in a final way.
But there will always be times when people suffer and we just don't now how it fits in the vast scheme of things. In such instances, we must trust that the Creator of the universe loves his universe and allows suffering for some greater purpose.
In the meantime, suffering in itself is not evil, and it can be a means for great good.
Next week: "The current bent of human nature is toward evil."
 A philosopher in the 1700s by the name of Jeremy Bentham tried to construct an ethic based purely on defining good and bad on the basis of pleasure and pain.
 Perhaps the greatest theological difficulty with evolution is the way in which it makes suffering a more intrinsic part of God's creation. See our discussion in the article on creation (C2).
 One of the philosophical problems with Augustine's version of the Fall is the way in which it assigns communal guilt, not on the basis of individual choice but on the basis of a single individual's choice, Adam's. Even parts of the Old Testament struggled with this notion of corporate guilt in relation to the captivity of Israel. More than one text in the Old Testament complains that "The parents eat sour grapes, and the children's teeth are set on edge" (Jer. 31:29; Ezek. 18:2). Ezekiel points out the ideal situation: "The one who sins is the one who dies" (18:4).