Unconventional love
One of the themes that are portrayed throughout the novel is the unconventional love between Spike and Billie. In the Planet Blue part of the novel relationships between the species are forbidden and punishable by death-this relates to human and Robo Sapiens relationships, but the two defy this because they have a strong connection. Billie is even reluctant at first because it is irrational, but succumbs to it as love is hardly ever rational. The novel explores and breaks the gender roles when it comes to relationships, as the love between the same sexes is not seen as a deviation from the norm, but a part of it.
Where is the limit?
The novel interestingly explores the limits of the human condition, how far humans are ready to push the norm and how badly it affects the society. This is shown with the example of Pink's husband, who is a pedophile, but he is barely accused of it, as the limit of children exploitation and exposure to the adult lifestyle is being pushed below their first decade. In the first part of the novel, Planet Blue, which is a story of a human society at a technological peak, but with the cost of the planet they live on because all the natural resources are exhausted and it's only a matter of them when the planet will destroy itself and all life on it, the limits of humanity are shown, as the line between humans who modify their appearance and live superficially and robots created artificially is closer than ever.
Artificial Intelligence
A significant theme explored in the novel is that of artificial intelligence that defies the beliefs of what makes a human humane, what makes a soul, the existence of a higher force, religious beliefs of the creator etc. Spike is the representative of a human-made artificial intelligence. She is a Robo Sapiens and in her creation she is meant to evolve based on her experience, similar to how humans evolved. As we see from the novel, the more she experiences the more humane she becomes, she begins to question herself, her existence and behaves defiantly to how she was programmed. Most significant is her relationship to Billie, which goes in favor with the notion that artificial intelligence is able to develop in a way similar to what one could see as an existence of a soul in an artificial body.
