At the core of Hardboiled Wonderland and the End of the World is the idea of the binary, two separate objects slowly coming together as one. This can be seen immediately from both the title and the chapters, which alternate between the Wonderland and the End of the world. The protagonist of Hard-boiled Wonderland, a calcutec, uses the binary property of his brain to process data, which is the main source of capital for almost everything in his world.
The other narrative, The End of the World, introduces us to another unknown narrator who can’t remember anything about his previous life. This is another interesting binary between the two stories, the Calcutec is struggling to preserve his identity while the End of the World narrator is struggling to discover his. The prose in the End of the World chapters is also markedly more fluid and poetic (almost dream-like), while the Hardboiled chapters tend to feel more cold and distant in its style.
The idea of a fundamental binary of identity is on display front and center here, asking to what extent our idea of self-hood is defined by our logical nature versus our creative impulses. If you take away a person’s ability to rationalize through prior memory, what do you have left? Would he still be human?
Humanity is so multi-faceted that it is impossible to say whether or not an individual can maintain their humanity without their sense of logic and reasoning or without their emotions and memories. Identity is built on memories and a person’s response to external forces, which factors in a person’s ability to apply logic/reasoning. However, whether or not a person can exist and still be known as a human being is a different question all together. The narrator of the “End of the World” sections is functioning as a human being, who, organically/biologically is still a human being, just without an identity and the ability to make rational decisions based on previous external forces that shaped his thinking, just as a person in reality with memory loss functions in society. The Calcutec, on the other hand, is exactly the opposite. But not living with emotions does not necessarily make him any less human biologically, but perhaps more mechanical internally. His perception is based on cold, hard facts, and that is how his identity is shaped, while the second narrator is built with a more pathos-based mindset.
The question you present at the end is interesting because it questions how we can define identity. Is the mind most powerful in this sense? Does it allow us to be; does it control our identity? The symbolism in the narrator allowing his Shadow escape the town alone, shows us that yes, there is some truth to the idea of mind over body. His Shadow contains his mind, and thus the release preserves his memory, his mind, and his identity. However the idea of identity can also be questioned within the framework of consciousness and unconsciousness (which is even referred to as “subconsciousness” indicating an alternate reality instead of a false one). Does the narrator even exist? In which state, and at what point in time? The End of the World sections are in present tense which shows the temporal continuity, and disconnect because it distinguishes the two stories. The idea of a “hard-boiled wonderland” emphasizes a dream that has solidified into reality, and is now tangible. Identity can then be drawn from both of these facets of mind and existence, and how one affects the other.