In Chapter 4, Kerans reflects on how few resources he will have to survive once Riggs and the rest of the crew leave, and on how ironically unconcerned he is. He uses an allusion to make sense of the strange choice he is making:
The tank on the catamaran outboard motor carried three gallons, enough for thirty miles, or a return trip a day for a month between the Ritz and Beatrice’s lagoon.
For some reason, however, this inverted Crusoeism—the deliberate marooning of himself without the assistance of a gear-laden carrack wrecked on a convenient reef—raised few anxieties in Kerans’ mind.
"Crusoeism" refers to the survival project of Robinson Crusoe, the protagonist of Daniel Defoe's eponymous 18th-century novel. Crusoe is a younger son of a modestly wealthy Englishman. He stands to inherit nothing from his father, so he sets out for America in search of new money for himself. After a shipwreck leaves him stranded on a desert island, he builds himself a makeshift kingdom of his own, ruling over animals and eventually an Indigenous man named Friday who reveals himself to be the island's other human inhabitant.
Kerans considers himself an "inverted Crusoe." Instead of setting out to build a future for himself, he is remaining behind as his comrades move into a future without him. He has less chance than Crusoe ever did of being rescued; even if the opportunity were to arise, he doesn't think he would want to be rescued. Nor does he envision himself building a personal fiefdom in the drowned city. The survival instincts and ambition that kept Crusoe alive are utterly lacking in Kerans's case. He ought to be terrified.
Beatrice, who first insisted on staying behind in the drowned city, is the one who inspired Kerans's calm resignation to an imminent death by exposure to the elements. And yet, when Kerans speaks with Beatrice later in this chapter, she indicates that she plans to drink herself slowly to death. Her use of alcohol to numb herself, combined with her mistaken belief that she has the time for such a drawn out death, throws Kerans's strange mindset into sharper relief. Beatrice has given up on survival and would rather enjoy hedonistic pleasures for as long as she can before she dies. Kerans, on the other hand, wants to stop fighting for survival so that he might experience the pain and suffering of a death that nature seems determined to inflict upon all of humanity sooner or later. If Crusoe built himself the conditions for his destiny to rule over his own castle, Kerans builds himself the conditions for his destiny to die in a global flood.
In Chapter 9, after Kerans almost dies in the underwater planetarium, Beatrice insists that it can't have been a suicide attempt. Kerans and Strangman aren't so sure, and Strangman uses an allusion to comment on how delicious he finds the situation:
Strangman shrugged theatrically. ‘It might,’ he repeated with great emphasis. ‘Let’s admit that. It makes it more interesting—particularly for Kerans. ‘Did I or did I not try to kill myself?’ One of the few existential absolutes, far more significant than ‘To be or not to be?’, which merely underlines the uncertainty of the suicide, rather than the eternal ambivalence of his victim.’
"To be or not to be" is the most famous line from an enduring Hamlet soliloquy, in which Hamlet meditates on whether or not he wants to continue living in a corrupt world where he is haunted by his father's ghost. Strangman thinks Kerans has an even more "interesting" question than Hamlet. His dilemma is not whether or not he wants to live, but rather whether or not he already tried to die. Kerans's uncertainty emphasizes his "eternal ambivalence" about life; whereas Hamlet had to come to a single, finite decision about suicide, Strangman argues, Kerans's question reveals that every single moment of his life has been characterized by the desire either to live or die. The fact that he wants to live right now clouds his ability to know what he wanted when he was inside the planetarium.
Kerans remains uncertain about whether or not he wanted to drown. His uncertainty stems partly from the fact that when he was underwater, he felt as though he were in a great womb, preparing to be born. In this sense, even if he tried to drown, his actions would not necessarily have been driven by a desire to die. Rather, drowning would have been a sort of attempt to begin life anew.
Strangman's comparison between Kerans and Hamlet draws attention to the corruption Kerans, too, would like to escape in the world he inhabits. Kerans has grown disaffected with humans' survival tactics and feels as though they are fighting nature through increasingly unnatural means. Whereas Hamlet imagines dying as a way into a different, more perfect world—the eternal afterlife—Kerans imagines it instead as more of a secular, natural process of returning to the beginning of the natural lifecycle. He wants to stop fighting the Earth and allow it to consume him. Whether or not this fatalistic refusal to keep surviving constitutes suicide is one of the lingering questions of the book.
Allusions to music, art, and art history are a motif in the novel. One rich example occurs in Chapter 10, when Strangman summons Kerans, Beatrice, and Bodkin to a dinner party for which he has decorated with an array of plundered art surrounding a giant Renaissance painting:
Its title was ‘The Marriage of Ester and King Xerxes’, but the pagan treatment and the local background of the Venetian lagoon and the Grand Canal palazzos, coupled with the Quinquecento décor and costume, made it seem more like ‘The Marriage of Neptune and Minerva’, no doubt the moral Strangman intended to point. King Xerxes...seemed completely tamed by his demure, raven-haired Ester, who had a faint but none the less perceptible likeness to Beatrice. As he cast his eye over the crowded spread of the canvas...Kerans suddenly saw another familiar profile—the face of Strangman...—but when he approached the painting the similarity vanished.
In the Bible, Esther is the adopted daughter of a Jewish man named Mordecai. She marries the Persian King Xerxes, a "pagan" (i.e. a Muslim, in this context). When Mordecai refuses to bow before any ruler except God, Xerxes's adviser Haman tries to have all the Jews sentenced to death. Esther saves her people by appealing to her husband on their behalf. There are several Renaissance paintings of Esther and Xerxes, though none with the exact name Kerans mentions.
Kerans is also slightly off in naming Houasse's "Dispute of Neptune and Minerva." This French painting depicts the two Greek gods' mythical fight to become the namesake for Athens. In the myth, Neptune loses the bid and floods the city in anger. The painting uses light and dark contrast to play up the divide between the two gods, depicting Neptune and the flooding Earth in dark colors beneath light clouds cradling Athena and several other Olympians.
Kerans thinks that Strangman has deliberately juxtaposed the art and artifacts of various European and Middle Eastern cultures in much the same way that Houasse juxtaposes "dark" Neptune and "light" Athena. The contrast emphasizes the culture clash at the center of Esther and Xerxes's marriage—and at the center of Beatrice, Kerans, and Strangman's love triangle. Beatrice is a "demure" Esther poised to marry Kerans, preserving not only humanity but also the European culture they both appreciate. Strangman is uninterested in cultural preservation. He wants a new, vicious world where the best scavengers survive. He lurks in the background like Haman or Neptune, waiting to seize Beatrice and wreak havoc on Kerans's world.
Neptune's flood is an apt metaphor for what happens to art over the course of the novel. Kerans starts out with a surprisingly deep knowledge and appreciation of European art history. He can recognize and contextualize paintings and symphonies he has never encountered in a museum or concert hall. However, as the temperature rises, he becomes more preoccupied with a drumming noise that beats louder and louder in his imagination, anticipating and echoing the bongos played by Strangman's pirate crew. His encyclopedic expertise in European art is gradually "drowned out" by the drums. (For instance, he begins mixing up the names of paintings.) It is as though not only a warmer climate, but also the influx of Black pirates, stolen art, and African music tumbles Kerans's sense of European art history into chaos, until it is no longer preservable. He eventually drowns the city all over again with water. He would prefer to destroy all the art rather than allow it to be decontextualized, stolen, and, in his view, cheapened.