O’Brien employs doubling and repetition of characteristics throughout the novel to deepen the text’s exploration of Unknowability as Part of the Human Experience. For example, the robber the narrator meets on the road answers most questions in the negative, recalling Mathers’s speech patterns. The robber also has a wooden leg, a similarity to the narrator: “He pulled up his own ragged trouser and showed me his own left leg. It was smooth, shapely and fairly fat but it was made of wood also. ‘That is a funny coincidence,’ I said” (49). Sergeant Pluck too suggests that it is best not to answer questions, and that one should “[a]lways ask any questions that are to be asked and never answer any” (62). Stated content about not answering questions aligns with the novel’s form as well. Increasingly, questions about reality versus hallucination remain unanswered as the novel progresses.

O’Brien uses sensory descriptions to create a dream-like atmosphere where the lines between real and unreal become blurry. As the narrator walks from Mathers’s house, he observes that “the sun was maturing rapidly in the east and a great heat had started to spread about the ground like a magic influence” (44, emphasis added). The idea of a “magic influence” once more implies that the narrator is no longer in the conventional world of the living. Similarly, the narrator’s conversations with the sergeant, in which the narrator asks after a non-existent watch and the sergeant repeatedly mentions bicycles, heightens the sense that nothing in this world makes clear sense anymore. 

The novel’s tone is also darkly comic, introducing an element of absurdity into the narrator’s interactions with others as reminders of his crime appear in different ways. Martin Finnucane appears as a double for the narrator not just in terms of his wooden leg, but also in his behavior, as Finnucane attempts to rob him just as the narrator robbed Mathers. Finnucane’s irreverent commentary on life blurs the distinctions between death and life, providing further hints that the narrator is actually dead: “There is nothing so dangerous [as life] […]. You can’t smoke it, nobody will give you tuppence-halfpenny for the half of it and it kills you in the wind-up. It is a queer contraption, very dangerous, a certain death-trap. Life?” (47, emphasis added). Using black comedy enables O’Brien to blend philosophical statements about the human condition with the suggestion that existence can also be futile and absurd.

This section of the novel also introduces a fixation with machinery, introducing the theme of The Interchange Between Human and Machine. Martin Finnucane suggests that he is “a robber with a knife and an arm that’s as strong as an article of powerful steam machinery” (48). Similarly, most of the narrator’s interaction with the policeman revolves around bicycles, with the narrator noting that it is “impossible to make the Sergeant take cognizance of anything in the world except bicycles” (64). This is another allusion to the narrator’s crime, as he and Divney went to meet Mathers on their bicycles in Chapter 1, and Divney hit Mathers on the back of the neck with an iron bicycle pump. In this way, bicycles become a key motif in the text that functions as a reminder of the narrator’s guilt. The policemen’s seeming fixation on retrieving bicycles becomes an indirect nod to the crimes that actually do need to be solved: those of Mathers’s murder by the narrator, and the narrator’s murder by Divney.