On their journey to the ranch, George discovers that Lennie is carrying a dead mouse in his pocket. When George questions him about the mouse.
Lennie replies, "Uh-uh. Jus' a dead mouse, George. I didn't kill it. Honest! I found it. I found it dead.... I could pet it with my thumb while we walked along."
To which major theme in the novella might this dead mouse most likely be tied?