Tomáš is a Czech surgeon who works at a hospital in Prague. He is a self-reflective intellectual with a keen interest in philosophy and an insightful understanding of the ideological underpinnings of communist society, government, and politics. The novel reflects a tumultuous time in his life, one characterized by both great happiness and great loss: He meets and marries Tereza, loses his surgical position because of his criticism of Czechoslovakia’s communist regime, and becomes first a window-washer in Prague and then a worker on a rural collective farm.

Tomáš’s interest in philosophy is one of his most important characteristics, and through it Kundera and his narrator interrogate the dichotomy between Lightness and Weight. Initially, Tomáš agrees with Parmenides that lightness (defined as a lack of attachments and responsibilities) is positive while weight is negative. He leaves his wife and son and engages in “erotic friendships” rather than traditional romantic relationships. These liaisons allow Tomáš to maintain an emotional distance between himself and his sexual partners and remain unburdened by the weight of affective connection. He is one of the text’s primary embodiments of lightness. It is understandable that Sabina, who also embodies lightness, is the favorite among his erotic friendships.