4 ideas
Lieutenant Christopher Hadley Martin is thrown into the Atlantic when his destroyer is torpedoed, at the moment he gives a helm order meant to kill his rival Nathaniel. The last chapter shows his body washing ashore with his sea boots still on, so he never had time to kick them off, and he must have died almost at once. The rock, shaped like the tooth his tongue keeps probing, was a world his mind built to avoid dying.
Martin recalls a Chinese recipe in which a fish is buried in a tin. Maggots hatch, eat the fish, then eat each other until one fat maggot remains, and he takes this as the model of how life works. His nickname 'Pincher' names this habit: he takes other men's women, jobs, friendships and credit, and treats any bond as food. The image turns predatory individualism into its end state, a single survivor who has eaten everything around him and is left alone in the box.
On the rock, Martin holds his self together by acts of self-assertion. He repeats his name, builds a stone figure to stand for himself, gazes at his identity disc and photographs, and imposes names and routines on a landscape that has no meaning of its own. The novel's claim is that the ego is not a given thing but a continuous act of refusal. Once that act stops, the self dissolves, which is why Martin cannot stop.
Nathaniel tells Martin that he must learn a 'technique of dying' into heaven, because heaven will feel like black lightning to anyone who has not let go of the self. Seen this way, damnation is not a sentence imposed from outside. It is the self's own refusal of an offered dissolution.