This is the first installment of a trilogy of posts I intend to make about Mormon responses to the problem of evil. The title is a turn of phrase I’ve ruthlessly stolen from John Keats because I think it best reflects the most popular answer given by LDS thinkers to date.
The problem of evil is essentially the tension that rises between a certain conception of God and the existence of a variety of evils in today’s world. Peter Berger aptly explains the importance of investigating any religion’s response to the problem of evil:
The anomic phenomena must only be lived through, they must also be explained-to wit, explained in terms of the nomos [Lawful Explanation] established in the society in question. An explanation of these phenomena in terms of religious legitimations, of whatever degree of theoretical sophistication, may be called a theodicy [God’s justification]. It is important to stress here particularly…that such an explanation need not entail a complex theoretical system. The illiterate peasant who comments upon the death of a child by referring to the will of God is engaging in theodicy as much as the learned theologian who writes a treatise to demonstrate that the suffering of the innocent does not negate the conception of a God both all-good and all-powerful. All the same, it is possible to differentiate theodicies in terms of their degree of rationality, that is, the degree to which they entail a theory that coherently and consistently explains the phenomena in question in terms of an over all view of the universe. Such a theory, of course, once it is socially established, may be refracted on different levels of sophistication throughout the society. Thus, the peasant, when he speaks about the will of God, may himself intend, however inarticulately, the majestic theodicy constructed by the theologian. 
In other words, what a specific religion says about evil will tell us a great deal about how that particular religion sees humanity’s relation to the entire universe. It also give us something to assess in terms of that religion’s credibility, namely its ability to give its adherents proper and useful categories for thinking about evil itself.
The traditional theodicy of the Western (Latin) tradition usually begins with Augustine. To Augustine, the creation and redemption of the world are key aspects to any biblical worldview, and the existence of evil and suffering posed a serious puzzle. If God created the world free from any contamination by evil (as He would surely do), how then did evil get introduced to the world?
Augustine’s answer (and lasting influence) is that evil is the consequence of human free will and its abuses. If there is evil in the world, it comes from its fallen creatures. This, of course, invites the question: how did humans get free will if they were created without it? Here, Augustine starts to lose steam. He blames the introduction of free will on satanic temptation, tracing it back to Satan, the fallen angel, and his rebellion against God. However, when asked how an angel who was created wholly good by a perfect Creator is even capable of rebelling, Augustine remains silent.
Another view comes from Irenaeus of Lyons (130 c.e.-200 c.e.) who was born somewhere near Smyrna in modern-day Turkey, though he later became Bishop of Lyons in 178 c. e. He is famous for his polemics against Gnosticism and his vigorous defense of the role tradition must play in remaining faithful to apostolic witness when confronted with abhorrent interpretations of scripture. Irenaeus’ answer to the problem of evil seems to take the opposite track of Augustine’s thought:
God made humanity to be master of the earth and of all which was there…Yet this could only take place when humanity had attained its adult stage…Yet humanity was little, being but a child. It had to grow and reach full maturity…God prepared a place for humanity which was better than this world…a paradise of such beauty and goodness that the Word of God constantly walked in it, and talked with humanity; prefiguring that future time when he would live with human beings and talk with them, associating with human beings and teaching them righteousness.. But humanity was a child; and its mind was not yet fully mature; and thus humanity was easily led astray by the deceiver. 
To Irenaeus, evil is a necessary component to spiritual maturation and is required for humanity to overcome before we can collectively reach the ‘adult stage’. Augustine looks back at creation and sees the fall of humanity from a perfect creation due to the misuse of human freedom, whereas Irenaeus looks forward to the eschaton and the final stage of God’s plan for humanity through the use of human freedom.
Mormon thinkers often find themselves favoring Irenaeus’ unique theme over and against the more traditional theodicy offered by Augustine and later Christian thinkers, so next installment we’ll take a look at two modern philosophers and their more current theodicies that relate to or borrow from Irenaeus’ ideas.