I'm reading Finders Keepers by Stephen King. Does anyone know what "Shit don't mean shit" means?
"Don't mean shit" = of no consequence.
The first "shit" seems to act like a pronoun. If the original noun isn't directly referenced then I'd guess it is talking about general life events.
Morris says it while he's being raped in prison, so it might mean
"It doesn't matter. It won't affect me."
Something like - Stupid things don't affect me.
You need to have mastered the context to get the meaning. Stephen King's book is the story of the murder of a reclusive writer named Rothstein and the secret burial of and the subsequent search for Rothstein's valuable manuscripts. King prefaces his book with two quotes. The first from Joseph Campbell:
It is by going down into the abyss that we recover the treasures of life.
Campbell studied and wrote about mythology and comparative religion. He maintained that all mythic narrative is part of a single overarching story. His quote means that you discover the important things in your life by confronting the unknown and the fearsome.
The second quote is from Jimmy Gold, who's a fictional character in Rothstein's books:
Shit don't mean shit.
The first shit can mean either 1) whatever meaningless uproar is going on in life or 2) ultimately worthless physical possessions. The second shit means the worth of excrement, in other words nothing.
It's all very wry and self-referential, with the contrast between the abstract goals of (the real) Campbell, who wrote about narratives, and the treasure of King's story as evaluated by (the fictional) Gold, who appears in a narrative within Finders Keepers.