James Baldwin's "Sonny's Blues" is a story with musicality. For with the narrative beginning in media res, the past and future are brought together with great poignancy; and, with these interludes of flashbacks, there are compressed tensions. This use of flashbacks by Baldwin allows the both the reader and the narrator to perceive how his "trouble made his [Sonny's] real." In addition, it also allows the reader to understand that Sonny is really the darker side of the narrator, and thus be more sympathetic to Sonny.
It is when the narrator remarks, "My trouble made his real," that he begins to understand Sonny, his darker side. For, then he notices the musical walk of Sonny--"I had never really noticed it before." Yet, at the same time, the narrator has held his preconceived ideas that he imposes upon Sonny in their conversation after they watch the street singer and Sonny talks of his addiction and of the addiction of others.
Finally, when the narrator accompanies Sonny to the nightclub, he understands: the tale of how we suffer is the "only light we've got in all this darkness." Sitting in the darkened corner, the narrator has an enlightenment, realizing that he and Sonny are two parts; Sonny's music frees if only there be a listener.
Freedom lurked around us and I understood, at last, that he could help us to be free if we would listen, that he would never be free until we did.
As the listener to both Sonny and the narrator, the reader comprehends, too, and achieves a sympathy beyond that of the narrator.