Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Serious, Philosophic, Artistic
The authorial voice of The Unbearable Lightness of Being – whether you consider it to be a fictional narrative character or the author himself speaking – doesn't shy away from analysis, contemplation, or heavy-duty philosophy. And quite often, he will step back from his narrative and draw larger conclusions about human tendencies based on his characters. More often than not, this consists of the narrator Telling You How It Is. A few prime examples:
When you sit face to face with someone who is pleasant, respectful, and polite, you have a hard time reminding yourself that nothing he says is true, that nothing is sincere. Maintaining nonbelief […] requires a tremendous effort. (5.5.6.)
Insofar as it is possible to divide people into categories, the surest criterion is the deep-seated desires that orient them to one or another lifelong activity. Every Frenchman is different. But all actors the world over are similar. (5.7.3)
Men who pursue a multitude of women fit neatly into two categories. Some seek their own subjective and unchanging dream of a woman in all women. Others are prompted by a desire to possess the endless variety of the objective female world. (5.9.1)
But the end game of Unbearable Lightness is not a philosophical nor political treatise – it's a novel. The fundamentally creative, playful, and artistic aspirations of the author are never undermined by the gravity of his arguments.