At the conclusion of the novel, Vonnegut reflects on what his puppets, the Tralfamadorians, had said, If what Billy Pilgrim learned from the Tralfamadorians is true, that we will all live forever, no matter how dead we may sometimes seem to be, I am not overjoyed. Judging by the preceding events that make the novel, it can be surmised that Vonnegut is being sarcastic. He knows that if that theory is true, then really all of the moments in history will go on forever. On the subject of black humor, Vonnegut noted that One day I was sitting on the beach at Cape Cod and this enormous bell jar was lowered over me and I managed to read the label. Vonnegut is referring to a paperback anthology of bleak and comical writers by Bruce Jay Friedman.
Black humor is more of a state of mind than anything.
It was connected to much of the turmoil that arose from the 1960's, politically and socially. That entails not only the bleak or absurd situations in life, but how one reacts to them, and sometimes, the best way is to just laugh. No one knows this better than Kurt Vonnegut.