One of the major symbols of Invisible Man is the briefcase the narrator carries around with him in the novel. The briefcase's purpose changes several times, and this also changes the meaning of the symbol slightly. In the beginning, the narrator obtains the briefcase at the battle royal. This grueling fight of black men versus black men, blinded and then electrocuted seems to stand as the distraction that keeps his mind away from the reality that he lives in. During the fight, he realized that the men in the arena shouldn't be fighting each other. They should instead be working together. However, at the end of the fight, he makes his speech and receives the briefcase. At this, he forgets everything he realized during the fight. He now is filled with false hopes and dreams, which he is willing to follow blindly even though he realized not even five minutes earlier that there was a more important issue at hand. Even after realizing the gold prizes on the electrified rug were fake, he still believes in the gold mine in his hands. The briefcase is a representation of the dream he wishes to live that will never come.
Later in the novel, as he prepares to leave Mary's house, he shatters a bank that is fashioned in the design of a black man that ate the coins put in his hands. The narrator destroys the racial insult and then, to cover up what he'd done, hides it in his briefcase. He hides it in with his former hopes and dreams. Perhaps this stands for the fact that he considers his former dreams just as offensive as the bank, that he perhaps finds his past and the people he used to know just as much of an insult as the bank. It could also stand for the idea that whatever his dreams will be, they will most likely contain prejudiced people with lots of money. This, of course, turned out to be true, as he later encountered the Brotherhood that soon betrayed him, and they can hardly be considered average folk considering the parties they held.
When the narrator later acquires Clifton's Dancing Sambo doll, he ends up eventually storing it in there as well. Again, he stores a racially insulting caricature in with what were his former hopes and dreams. By now the briefcase also contains the papers from the Brotherhood, such as his new name, his instructions, his work, and other things. This could be symbolic that his new hope is one of despair and prejudice, that he's actually chasing something that he should really be trying to avoid. Perhaps it might stand for the fact that the Brotherhood's inaction was what destroyed Clifton in the end, and sought then to erase him from history despite his sacrifice. Maybe it symbolizes the fact that Clifton's possible hopes and dreams were consigned to the same place, position, and importance, as the organization that had sorely disappointed and angered him.
Lastly, the briefcase was used as a weapon to escape Ras. This could be almost like saying that the events of his past, all of his former hopes and dreams gone sour and all the insults made against him, in the end strengthen him and allow him to escape the hatred of others. All the events of his past have empowered him, and he has learned from them well enough to move on and start again. Perhaps the fact that he used it against Ras's henchmen can be symbolic of who he really sees Ras helping.
One other thing of importance is the fact that the superintendent that awarded it to the narrator after the battle royal stating that it would at some point "be filled with important papers that will help shape the destiny of your people" (Ellison 32). The generous donor of such a destiny-bearing carrier? Shad Whitmore. No guesses as to what is implied by one with a name made up of the words "white" and "more." Obviously this is a nod to who controls the destiny of the narrator for the majority of the novel.