Metaphor for Failure
The “real” Rheya died long before Kris had gone on his interstellar mission to Planet Solaris. She had taken her own life through a lethal injection. Although there are snippets of details concerning their relationship one fact is clear: his relationship with Rheya was difficult to the point of her choosing death as a better alternative to living with Kris. The emotional trauma of their relationship as well as her suicide is brought by Kris to Solaris and this emotional baggage forms the emotional framework of the simulacra that Solaris creates from his thoughts of her producing an emotionally needy, excessively clingy creature that is difficult to deal with not only because of her emotional instability but also because of its inherent inhuman capabilities. These characteristics make both the memory of the real Rheya and the first artificial Rheya metaphors for failure; his failure at being a spouse and his failure to honor the memory of his deceased wife.
Metaphor for Hope
When the clone Rheya continues making an appearance on the station to Kris. The clone Rheya is patterned so closely after Kris’ last memories of his deceased wife that it responds to situations in a similar manner: clingy, emotionally unstable, and prone to self harm. Kris however actually manages to fall in love with the simulacra of Rheya, realizing that perhaps this “new Rheya” is precisely what he had needed, a second chance at making things right—even if means playing at romance with an alien clone. The clone Rheya, in this regard, may be understood a metaphor for hope, a second chance, a rare opportunity that not everyone gets.
Metaphor for Possibility and Truth
The planet Solaris as well as the ocean-sized liquid being it houses is a metaphor that can be understood on various levels. On one hand both the planet and the alien being may be seen as a metaphor for possibility and truth. The thought-constructs it creates are pulled from the deepest, most repressed memories, and for some their fondest fantasies come to life. Why it chooses to interact with humanity in this way is never revealed but the simulacra either cause the explorers to self-destruct as they are incapable of facing the truth about themselves or, like Kris, who faces the strangeness of this new reality head on and sees all that possibilities that be had—including the possibility for redemption that he never even knew he was looking for.
Metaphor for Ignorance and Pride
Kris Kelvin first encounters the cybernetics specialist Snow as he is on the verge of a mental breakdown, haunted by a Visitor known only through Kris’ unflatteringly racist description of “Negress.” Snow’s Negress is of great significance as a literary device and an allusion drawing a parallel to the intergalactic expedition that the Solaris team is on and previous historical expeditions. Many, if not all, exploratory expeditions were fueled by the lust for glory, vanity, or plain greed. Often these historical expeditions put the native populations of these so-called “undiscovered territory” as a significant disadvantage, being exploited as slave labor or worse, driven to extinction via genocide. The appearance of the Negress alludes to the Solaris’ team’s "mission of discovery” to be nothing more than a glorified excursion motivated by pride and ignorance, just like so many expeditions in the past.
Metaphor for Man’s Limit/The Limits of Man’s Knowledge
Solaris tests the crew’s limits and, by extension, humanity’s limits, specifically the limits of his scientific knowledge, technology, and even the depths of personal understanding that the crew members have of themselves. Their technology, however advanced and varied, are unable to yield up for the team any sufficient answers for the mysteries of the planet. Things take a turn for the worse when the ocean-organism begins to create artificial beings called Visitors—and even the Visitor’s purpose, whether they’re attempts to more effectively communicate with the crew or to test their motives, is never clearly understood—begin to make an appearance to the crew with fatal results. Solaris, both the planet and the mega-being, is a metaphor for the limit of man’s knowledge, both of his science and even his faith.
