By writing myths of creation for his world, Tolkien introduced some of the same philosophical issues that we face in the real world. Billions of people believe that our world had a benevolent, and even omnipotent, creator and must reconcile that with the presence of evil. When one then adds the concept of free will, which is necessary if creatures will be held accountable for their actions by an all-just God, the issue becomes even more tangled. This concern has made countless people abandon their faith and has preoccupied the most, if not all, of the greatest theologians. But if this question has plagued humans for millennia, why would Tolkien subcreate such a muddle for himself? After all, he could have written a Manichean myth (with two gods, one good and the other evil, of roughly equal power) and done away with the problem. He could have abstained from the issue entirely by not giving his world a beginning. Since he clearly did not have to engage with the problem of evil, it must be in his legendarium because he wanted it there. Telling stories about difficult philosophical questions gives both teller and audience more ways to conceptualize and face these issues.
The tale of Numenore is an interesting example of such a story. Men who fought against Morgoth are given the beautiful island of Numenore. It is the pinnacle of natural beauty and human wisdom, as the Numenoreans are taught many things by the elves. The inhabitants are given long lives and peaceful deaths. They are great explorers and sail to Middle Earth to help others. Their exploratory ambition is limited only by a ban that forbids them from sailing so far west that they cannot see their island. Eventually, however, they become greedy and dissatisfied. Where they had once gone to Middle Earth to aid and heal, many started to form colonies to extract tribute. They also began to fear death and at the same time to begin to distrust the elves. An already corrupt king took Sauron as his counselor and was tricked into believing that he was more powerful than the Valar, that Melkor rather than Eru was the supreme deity who deserved their honor, and that he should break the ban on sailing to the Undying Lands to claim immortality for himself. When the king leads an armada west, Eru destroys Numenore and changes the geography of the world, removing the Undying Lands and making it round. Some Numenoreans remain Elf-friends and survived the destruction of the island.
It is in many ways a familiar tale. Men are given a paradise, though this time it is an island instead of a garden. They have only one prohibition and violate it because of the mistaken belief that doing so will make them become like gods. The island is submerged into the sea, and is even given the name Atalante, which in Tolkien's Quenya means "the Downfallen." These similarities make the story not only more interesting to the audience but also signal its pertinence to those of us who are already concerned with sin and the loss of paradise.
It is clear then that one of the questions this story asks is how do people living in paradise and goodness turn to evil. Unlike the Biblical Fall, there is already sin present in the world even before the creation of the island, and while going against their ban is their greatest crime, the Numenoreans already sin. (Tolkien writes about the Fall elsewhere). In a way, this makes the story easier to think about. After all, how can one be culpable for sinning if one cannot distinguish between right and wrong. It is interesting to note, however, that though evil is present before Numenore, the Numenoreans themselves do not seem particularly sinful for a millennium. As was mentioned above, they go to Middle Earth because of the joy of discovery and also to help their kin, even though they eventually desire to subjugate the men of Middle Earth. They also become greedy for earthly things, which is one of the reasons for their brutal colonialism. One might think that this progression is inevitable. After all, the are set apart from others and given much greater gifts. Does ennoblement inevitably lead to hubris, greed, and domination? Are they at fault for their rejection of the law that has been placed on them because it comes from a fear and hatred of death? After all, if death is not an evil, why would it be a gift to receive longer life? Moreover, they act because they have been deceived by Sauron. In essence, do the Numenoreans have free will? It is clear from the text that they do. If it takes two millennia for a law to be broken, then surely it is not inevitable. Even at the end, there are still some who refuse to do so. If Tolkien thought that nobility automatically leads to overweening pride, then how can Aragorn be a great hero? The return of the king is clearly bad if that king will act as the men of Numenore did. The Numenoreans reject the identity as it had been given them by Eru and communicated via the Valar and Elves. They failed to recognize their mortality, but surely it is possible to know at least that about oneself. They made the choice to trust Sauron and distrust their true friends, the elves. In fact, as a race of Elf-friends who are given wisdom and skills by the elves which can then be given to the rest of humanity, by turning from the elves they rejected their identity again. It seems then that all the men of Numenore throughout all its generations had to decide whether to defy the ban or not and it is only a small subset of those who decide to do so. Incidentally, this is quite unlike how many Christians view the Fall of Man in which it seems inevitable that the first humans would sin. Perhaps Tolkien thinks that this is an incorrect view.
It also seems clear that their sins are truly evil. They take away the freedoms of other creatures in Middle Earth and are even destroyed by their desire to control in that it is through conquest that they bring Sauron back to Numenore. This sin is for Tolkien the greatest; it is this take over of the will that makes the Ring so wicked. Though they sail west to gain greater freedom by conquering their lords and extending their lives indefinitely, they do not seek something good, even if freedom and life are good, in part because they have ceased to know themselves.
As Numenore is destroyed, the straight path west to Valinor disappears. The straight road is bent. Perhaps this gives us another lesson: there are some things that humans will never completely understand, even if we can approach the truth. This seems more probable if one agrees with Flieger that Tolkien's goal in the Silmarillion is to write about the metaphor of understanding as enlightenment. If the road to Valinor is gone, humanity can never see the light of Valinor and will therefore not understand. It is interesting that while the Biblical Fall happens as a result of gaining knowledge, the hubris of the Numenoreans leads both to the destruction of much of the wisdom they had on the island and the impossibility of seeing divine light of understanding.