The novel centers around bicycles. Sergeant Pluck and the other policemen talk incessantly about bicycles. Not only are bicycle-related offenses the majority of the crime the policeman deal with, bicycles are also the key aspect of the novel’s surrealism: People in the village are becoming more bicycle, and their bicycles are becoming more human. Through this theme, O’Brien raises questions over the interchange between human and machine. 

The Sergeant’s discussion of how people in the village are becoming more machine-like speaks to the novel’s interest in dehumanization and the problem of boundaries between humans and machines:  

People who spent most of their natural lives riding iron bicycles over the rocky roadsteads of this parish get their personalities mixed up with the personalities of their bicycle as a result of the interchanging of the atoms of each of them and you would be surprised at the number of people in these parts who nearly are half people and half bicycles (88, emphasis added).

The collapse of identity as a result of becoming overly reliant on machines suggests that people can lose their human personality if they do not clearly differentiate between the tools and technology they use and their own selves. The novel represents this problem to more literal and comedic effect through the human-bicycle hybrid phenomenon. 

The novel also addresses collapsing boundaries between machines and humans by depicting a chronic lack of meaningful human connection, leading to an overly intense fixation on bicycles. Throughout the novel, the narrator lacks intimate relationships and interactions with others. His connections with other characters are usually superficial or contentious, such as his mistrust of Divney and his difficulties communicating clearly with the policemen. The most intimate moment he experiences is when he is riding the Sergeant’s bicycle. He thinks of the bicycle as a “she,” and experiences a close connection and feeling of attunement with her. This suggests a form of pseudo-intimacy, highlighting that neither the narrator’s life nor his experience of hell include real, human-to-human connection.

Finally, the blurring between human and machine is also reflected in the narrator’s experience of “eternity.” The elevator he takes demonstrates a degree of implied moral reasoning and judgement, refusing to raise the narrator back up if he enters with valuables he did not have on the way down. The elevator thus embodies the kind of humane moral reasoning the narrator lacks, reflecting back both the avaricious motive behind his crime in life and suggesting that, in this instance, a machine is demonstrating more human qualities than the novel’s human protagonist.