LitCharts assigns a color and icon to each theme in The Unbearable Lightness of Being, which you can use to track the themes throughout the work.
Time, Happiness, and Eternal Return
Lightness, Weight, and Dichotomies
Sex, Love, and Duality of Body and Soul
Words and Language
Power, Politics, and Inequality
Summary
Analysis
A few days later, the tall stranger comes back to Tereza’s restaurant and begins to flirt with her. He tells her that he is an engineer and lives nearby. It was only “sheer chance” that he came into the restaurant a few days earlier, the stranger says.
This moment reinforces Kundera’s fate/chance argument. Whereas Tereza sees Tomas as her fate, the tall stranger is portrayed as “sheer chance,” and in this way, not at all important.