Google produced a bewildering array of discussions about themes and tropes and I found it hard to nail down a definition (most stumbled over several meanings and seemed circular, to me).
I liked this definition of theme:
theme (theem): a common thread or repeated idea that is incorporated throughout a literary work.
A theme is a thought or idea the author presents to the reader that may be deep, difficult to understand, or even moralistic. Generally, a theme has to be extracted as the reader explores the passages of a work.
The author utilizes the characters, plot, and other literary devices to assist the reader in this endeavor.
One theme that may be extracted by the reader of Mark Musa’s interpretation of Dante’s The Divine Comedy Volume I: Inferno is the need to take account of one’s own behavior now, for it affects one’s condition in the afterlife. One example of this theme can be found in Canto V – “…when the evil soul appears before him, it confesses all, and he [Minos], who is the expert judge of sins, knows to what place in Hell the soul belongs: the times he wraps his tail around himself tells just how far the sinner must go down†(7-12).
Dante’s use of literary techniques, such as imagery, further accentuates the theme for the consequences of not living right, for he describes “the cries and shrieks of lamentation†(III:22), “…the banks were coated with a slimy mold that stuck to them like glue, disgusting to behold and worse to smell†(XVIII:106-108) and many other terrifying examples of Hell.
In truly great works of literature, the author intertwines the theme throughout the work and the full impact is slowly realized as the reader processes the text. The ability to recognize a theme is important because it allows the reader to understand part of the author’s purpose in writing the book.
I found this observation about tropes to be useful:
Feb 8, 15:23 by Daniel M. Kimmel