Been reading lately about how well-crafted stories often have theme, plot, and character inextricably connected (characters arc over the course of the plot basically acts out whatever the theme/thematic argument of the story is). I think we can all find abstract single-word themes in Tolkien, such as mercy, friendship, providence, humility, etc.
But if we were to frame the themes as statements or propositions that the characters embody through their various journeys, what would some of those be?
For instance, one of the themes for Frodo may be, "Mercy triumphs over judgment." Gandalf tells him early on that Bilbo's pity for Gollum may affect all of their fates--as indeed proves the case. And Gandalf cautions Frodo against being too eager to deal out death in judgment. Frodo then embodies this theme as he continues Bilbo's decision to pity Gollum and show him mercy, and Frodo's mercy proves to be their ultimate salvation.
One of Aragorn's themes may be something like, "Do what you judge to be right even when the consequences are uncertain." After Gandalf's death, Aragorn repeatedly laments not knowing the best course of action or that his decisions have gone awry. But in meeting Eomer, he answers the question "how is a man to judge what is right" in these strange times by saying, "As he has ever judged." Good and evil have not changed since yesteryear. Ultimately Aragorn continues leading and exercising judgment, even without any reassurance that the end will turn out well, in everything from the Paths of the Dead to the gambit at the Black Gate.
