Ralph Ellison's Invisible Man deals primarily with issues of identity, specifically, Black identity in America. The question articulated indirectly in the opening chapter about how the protagonist's identity is tied up with race (and exploitation) is treated at length in the novel's closing chapter.
“What and how much had I lost by trying to do only what was expected of me instead of what I myself had wished to do?"
The action that takes place in between these two moments in the narrative explores various ways in which the unnamed protagonist tries and fails to develop a stable and positive identity.
In the opening chapter of the novel, the protagonist participates in a gruesome spectacle put on for the entertainment of the town's White leaders. In this episode he is humiliated and beaten. When he finally gets to present his speech to the White audience, the protagonist does not realize that his message is one of complicity as he suggests that advancement/progress for Blacks must come with humility and even an acknowledgement of subservience. (The novel suggests later that this rhetoric is meant to echo that of Booker T. Washington, a successful Black leader who emphasized education and self-reliance and who also appealed to the higher nature of Black and White alike.)
The irony in this speech is not recognized by the young protagonist. He does not see that his grandfather was right when he argued that Whites would seek to exploit him if he let them. In accepting the patronage of the men who forced him to grovel for money, watch a stripper perform, and fight blindfolded with a group of boys, the protagonist is certainly being exploited.
Through the novel, this pattern continues. The briefcase given to him along with his scholarship becomes a symbol of the protagonist's blind belief in the potential for self-empowerment and, at the same time, a symbol of his continued (almost clownish) exploitation by others.
"As a student, the narrator might well imagine himself as a would-be Booker T. Washington, but his goals are preset and accommodationist" (eNotes).
Caricatured and objectified by a trustee of his college and abused in his trust of his college dean, the protagonist experiences his first loss in the context of his dream of personal advancement. The path to success he had been convinced of, by the same men who abused and rejected him, is shown to be part of a larger system of carefully protected power. Higher education does not empower the protagonist but exploits his naive belief in its intentions to do so.
Similarly, the protagonist is shepherded into service with a political movement where his abilities as a public speaker are used and his personal ideas are explicitly silenced. He is once again used by a program that fails to recognize his humanity and his value, despite the fact that he is supposedly working for social progress.
The one job the protagonist gets as a laborer follows a similar pattern of racial bias where he encounters a Black man working as an engineer at a paint factory but being paid as a janitor. This man is protective of his own modicum of power and security and so ends up violently expelling the protagonist from the job.
At every turn, the narrator seeks a role that will give his identity some meaning but finds that his humanity is denied. His value as a person with ideas and feelings of his own is not recognized.
“I am invisible, understand, simply because people refuse to see me. Like the bodiless heads you see sometimes in circus sideshows, it is as though I have been surrounded by mirrors of hard, distorting glass. When they approach me they see only my surroundings, themselves or figments of their imagination, indeed, everything and anything except me.”
The novel's thematic commentary is focused on the ironies of progressive race politics as they appear in various situations (at the college, in the Brotherhood, etc.). Particularly, the novel generates a carefully problematic statement on the possibility for social change, taking pains to present this problematic via a narrator who himself only partially understands his ultimate plight.
Perspective on race is not the entire problem for the protagonist. Power and corruption are equally responsible -- if not more responsible -- for the protagonist being chased in the end down a dark hole. Yet, the narrator does not condemn the power structures and moral failure of those who have exploited him. Instead he reflects on the idea that his humanity has been denied him and thinks that attitudes and perspectives are the mechanisms that drive his identity conflict.
There is quite a bit in play, conceptually, as the protagonist narrates his thoughts in the closing chapter. This is part of the power of the work as we encounter a figure who has been overwhelmed by the forces he finds himself pitted against.
We should also note that in the novel's treatment of Booker T. Washington and its allusions to Marcus Garvey, there is a good deal of consideration made for each approach to Black politics and social theory. However, instead of developing an argument as to which approach is the best approach the novel depicts a situation wherein these approaches are seen as complex responses to a complex set of circumstances. To its credit, the novel does not simplify its issues down to a final agreement with the grandfather character and his embittered cynicism.
The novel certainly fosters some cynicism, but presents a set of ideas that illuminate the entrenched difficulties faced by Black Americans seeking positive and meaningful identities in this era.