Human life is meaningful as long as it is interesting and fun.
In the stories, any serious attempt to create Utopia or a perfect system comes from the robots, not surprisingly, but actually, when the humans check the place out, the HPLD, that is, they find that basically it's super lame and boring. And slaying dragons to get maidens? That might be meaningful, but as the robots show, it's kind of hackneyed. So in the story, the humans decide to split the difference, making the most of each moment and trying to stay entertained.
Romance as the core of meaning, but only in a certain sense
By having the robots enact our mythic tales of knights saving maidens from dragons, the authors reaffirm that basically, the meaning of life is to conquer difficult situations and to enjoy the spoils. But that is seen as an insufficient answer, or at least only a partial answer. The true meaning comes from the thought experiments and the attempts at humor.
Humans and robots as a kind of mythic relationship
One of the most fun features of this collection is that robots are treated as just below the humans. The humans have the miraculous abilities to create new robot life and perform miraculous healings, so they're basically like gods to the robots. Although, given the current predicament of AI, this imagery may not seem accurate, but it also didn't make much sense when it was written, at the height of the cold war in Poland. So the thematic meaning here is that robots are not gods—if anything, we're like gods, and we're responsible for what happens.
The value of the unknown
The fact that the stories exist at all is a testament to the author's ability to indulge fantasies and ask "What if?" questions. So, not surprisingly, that theme runs through each story in a deep sense. Each story presents the reader with a thousand speculations about the nature of reality. It's a kind of pop-philosophy where the most entertaining ideas or the most novel ideas float to the top.
The order of the universe and the chain of being
Although this one may not be as obvious, it is still very evident. Look at the structure of the robot universe. It's a feudal hierarchy, just like the humans do, with castes and roles, just like the humans do. By reaffirming this tendency to self-organize, the author reaffirms the structure of the chain of being, which is an ancient theme and an important aspect of any mythic literature. And since the novel relies upon the creation of a sci-fi universe, it is mythic. This is a common feature of fantasy worlds.
