Solaris' critique is two-pronged, considering two distinct subjects: the pursuit of advanced scholarship in educational institutions and understanding human psychology.
The critique of education is funny. As scholars attempted to understand the sentient planet, their theories mushroomed. Theories and countertheories were spun on and on forever to the point that none of the theories meant anything. Creating theories and arguing theories about the ocean became a self-supported field of study. Having an answer was no longer required. The answer was the question. The question made scholars out of nobodies, gave academics something to go on talking about forever because people wanted to know the answer but the answer was never satisfying.
At least the academic answer was never satisfying because the academic approach was the approach of theory--theory as a field of study, which includes identity politics, structuralism, poststructuralism, reader-response theory, new historicism, eco-criticism, gender theory, queer studies, latinx, Marxist criticism, postcolonial studies, cultural studies, and on and on. The bottom line is that these studies are interested in proving that nothing is what it is. That doesn't mean that things don't mean anything--it just means that meaning isn't what we thought it was. Things and the meanings they have are always in flux, interpretable, diaphanous, hybrid. The academic approach sets ideas free of reality, sending everything adrift so new interpretations can be added to the palimpsest of discourse.
There is no meaning, only discourse.
There are no words, only langue.
Enough of that. What about the psychological approach.
Solaris, a sentient planet, forces its visitors into self-reflection. Studying the world of Solaris--no matter who you are--is to study yourself. The planet studies each of its visitors and selects a person from the visitor's past to send to them. That Solaris generated person is created as a flesh and blood, living entity. The selected person is always important in the life of the visitor--a lover, a child, a friend. The planet is uniquely skilled at selecting a person for their visitor that had a mixed history with them.
Why?
Because the perfect selection evokes a range of emotional and psychological responses in the individual, including love and hate, wonder and fear, contentment and remorse, elation and depression, care and jealousy. Dealing with the polarities of human emotional experience makes individuals face themselves. It's hard to mask feelings and thoughts when dealing with the extremes of human emotional experience.
And now I will return to the critique of educational institutions to show how it parallels the question of human psychology.
Here is a question:
What effect does a sentient, mind-reading world have on the humans that study it?
Solaris is proof of concept for quantum physics--observing a given subject changes that subject. Expecting one psychological state changes that psychological state. All human reality is in flux. Our minds are never the same from one moment to the next. No dependably accurate definition of who we are can ever be established. Our ontology is a moving target. We are a palimpsest of ourselves. Tomorrow I will be all that I was today and more. But what do those changes mean?
Are all those changes no more than pretty undulations sans meaning?