[obloquy]

I wouldn't take an utilitarian approach - that his element is not evil because it worked out for good.

Well that's not what I'm saying, either. Melkor's power was not evil power. I express my thoughts on this more completely in another thread:

Classifying Melkor as "evil" is questionable. He sought to further his own purposes, and since those were in disharmony with the other themes in the Music they were resisted and this caused strife. What's interesting is that, while the Valar did not know what physical manifestation their music would have, Iluvatar did and still he did not condemn Melkor. Instead he declared that ultimately his will would be accomplished, with Melkor as his instrument.

At this point it had all been laid out for Iluvatar to see. This suggests to me that Melkor had not done anything "evil"--at least in the absolute sense--in the eyes of his father. The corruption of Arda becomes minor on this universal scale, and the "big picture" had not been altered from Iluvatar's original purpose. Melkor, at the time when he had already wrought all his corruption, was above (or outside the jurisdiction of) the concepts of "morality" or "good and bad" that we and the Children of Iluvatar are familiar with and use as guides to make our decisions. Melkor merely resisted the vision of his Creator, which he was created with the will to do and this action was apparently still within his rights. Iluvatar did chastise him, but then made it clear that the beauty of his vision had not been compromised:

Obviously. That's the point. All of Melkor's discord did not corrupt Iluvatar's plan, so how can we call it evil without maligning Iluvatar himself? He didn't fix the Music or remove Melkor's contribution.

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[Iluvatar] didn't oppose it, he contained it. He humbled Melkor and silenced him when he saw fit, but he did not oppose the theme Melkor had sung. Had he opposed it, he would not have claimed to be its "uttermost source."

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I'm not saying that Iluvatar favored Melkor's discord, but I am saying that it was permitted and within Melkor's rights.

Good post, and it echoes my feelings on the definitions of good and evil. God isn't just "good" because he never makes an error that leads to bad, he is the ultimate good because that's what he chooses to define himself as. He is the arbiter on a tier above the two sides. Since Melkor and the rest of the Valar were installed as creators and gods of Arda, they had a similar right to do what pleased them without moral constraint. As far as I can remember Iluvatar does not provide a moral structure to guide their actions, apart from his direct communication with Manwe. Morality is designed to guide physical beings. Similar to the Biblical account of the origin of the demons, once Melkor incarnates himself and begins to break the moral laws of the Incarnates, he is no longer above those laws and is then subject to condemnation.