The pitfalls of capitalism
The most pervasive — and important — theme in the novel is the pitfall of capitalism. Chen's story, and the story of the Shen Fever more generally, is a metaphor for how capitalism causes people to sink into a routine like a zombie. As they become more and more engrossed in their routine, people begin to ignore some of the most foundational things in their life. Then, they die — alone and devoid of any meaningful connection with other human beings.
This, Ma argues, is like life under capitalism: the worker toils away, working day to day to earn enough money to survive. They spend most of their life working that way, only to have the last few years of their life left to enjoy what they can. That's why, Ma argues, capitalism has many pitfalls. Chief among those pitfalls: is that it ignores humans and humanity.
Monotony
Another important theme in the novel is monotony, which is a key feature of those working in a capitalist system. In the novel, Ma portrays Chen as working in a job that she finds unfulfilling, doing the same thing repeatedly and to the point that she becomes wrapped up in the monotony and devoid of any emotion surrounding her job and work. And Chen is not unique: everyone in capitalism, Ma argues, must descend into monotony to survive their lives day-to-day. That, she also argues, is one of the worst aspects of the economic system.
