A place to start in the Christian life is with an understanding of the nature of evil. There are two basic views concerning the nature of evil. Tolkien and Lewis help clarify these views. The Bible gives necessary background. Here are the two views:
1. Manichean dualism. In this view evil and good war continuously with neither seeming ever to win the day.
The most famous philosophical statement of the orthodox Christian view of evil is that of Boethius, a Roman senator in the early 6the century AD. De Consolatione Philosophe, “Of the Consolation of Philosophy,” was written while Boethius, a Christian, was in prison waiting to die on charges of plotting to restore Imperial rule. Boethius was tortured to death in 524/525 AD. His reflection was not idle mental meandering. He was struggling with the thing itself... with evil. “The Boethian view is that evil is not something in itself. What people identify as evil is actually the absence of good.” [1]
Tolkien struggled with the nature of evil. He spent time in the British Army and served in the Battle of the Somme, one of the most famous apparently useless expenditures of human life in the history of warfare. Tom Shippey notes that Tolkien was one of many authors in the 20th century who had served in the century’s "great wars" and struggled to understand the nature of their experience of evil.
Tolkien’s view is expressed throughout The Lord of The Rings. Frodo comments to Sam in the Tower of Cirith Ungal that evil cannot create ... “not real new things of its own.” This illustrates the Boethian view or the orthodox Christian view of the nature of evil. C.S. Lewis adds in Mere Christianity, “… furthermore evil was not created; it arose when human beings exercised their own free will in withdrawing their service and their intentions from God; in the end when the divine plan has been fulfilled all evils may be annulled, cancelled, brought to good, as the Fall of Man was by the Incarnation and the Death of Christ.”[2]
Some evidence for and against the Boethian view is as follows. All who do evil excuse themselves in terms of what is good. Therefore evil is an absence of good. Evil is a parasite not an original thing. An illustration are the Orcs in Tolkien’s Lord of the Rings. Though the Orcs are understood to be "forces of evil" they admire and condemn based on their own moral judgments of the good.
One may add that Bible suggests that human persons are greatly influenced by spiritual forces. Spiritual forces are ultimately either of God and the light (angels, e.g.) or they are forces of the darkness and followers of the angels who rebelled against God, that is Satan and his followers (demons). A person not influenced by benevolent spiritual forces, one who is empty so to speak of spiritual influences for good, is capable of being influenced by demonic forces.
Though evil is not something in and of itself - but rather the absence of something else (the good of God) - evil does express itself in the world human persons inhabit. Whenever evil does express itself good is in opposition to it. It is in the nature of Reality that in the spirit world the forces of darkness are in every instance opposed to the forces of light.
Though on the spiritual plane these two forces are always clearly delineated on the human plane there is often considerable shadow. An example is the allied opposition to Hitler's war machine in World War II. Though the allies were not uniformly expressions of the forces of light and Hitler's war machine was not uniformly an expression of the forces of darkness the allies were clearly forces of good in their opposition to the Nazi forces of darkness and evil.
[1] JRR Tolkien: Author of the Century. Shippey, Tom. Boston: Houghton Mifflin, 2002.
[2] Ibid, 131
