A Note on Characters
We know that The Unbearable Lightness of Being can seem like a bit too much, from the title on forward. Between the tricky narrator and the strange mix of philosophy and fiction, this novel can be overwhelming. But before you throw yours hands up in confusion, we have a few tips for you to keep in mind before we launch into these analyses.
First, don't feel the need to assign labels to the characters. You might read materials that claim Tomas = lightness, Tereza = heaviness, Sabina = lightness, and so forth. This method is limiting, and would probably be untrue no matter how you label the characters. Most importantly, you'll miss out on most of the novel if you take this approach.
What might be helpful instead is to recognize that Kundera uses each character to explore in depth one (or more) of his philosophical ideas or questions. For example, while all the characters in some way struggle with es muss sein, it is Tomas who deals with the issue explicitly. While all the characters are subject to the soul/body duality, it is Tereza who is obsessed with the idea. What we'll do in these analyses is explore the philosophy of Unbearable Lightness by taking a closer look at its characters. This is what the narrator does too: the characters are concrete representations of the abstract ideas.
That being said, you should also keep in mind that the storylines and characters in Unbearable Lightness also have artistic value as fictional creations. They're not just there for the philosophy. This is a novel and not a treatise, after all. That's why we can call Unbearable Lightness both a work of ideas and a moving love story.