While Man could learn to create a Mind, He could never create a Soul.

Tolkien touches on this in his writings. When the dwarves are created, since Aulë the Smith didn't have access to the Secret Flame, his creation had no souls and no will of their own. Ilúvatar told him he shouldn't have created them without his permission so, sort of like Abraham getting ready to sacrifice Isaac, he goes to destroy his creation. Ilúvatar stays his hand, "adopts" the dwarves as his own, and gives the dwarves souls but says they have to sleep until the Firstborn (elves) wake first. Unlike Morgoth's pride and selfishness Aulë's humility won Ilúvatar's mercy. Tolkien was a devout Catholic so it isn't surprising that he had many analogous themes in his writing.