In Part 5, we return to Tomas after his departure from Zurich and arrival in Prague. His boss, the chief surgeon, asks him to sign a paper retracting an article he wrote in 1968.
In the politically dangerous article, Tomas used the tale of Oedipus to write an article criticizing the Czech communists. (Note: Oedipus Rex is the story of a tragic hero, Oedipus. An oracle tells him he will kill his father and marry his mother. To avoid these horrors, Oedipus leaves his home. Years later, he unknowingly returns to his own city, and, not realizing what he does, kills his father and marries his mother. When he understands that he has fulfilled the oracle's prophecy, Oedipus pu ts out his eyes and steps down from the throne.) Tomas compared the Czech Communists to Oedipus. Like Oedipus, the Communists claim they did not know what they were doing, and could not foresee the consequences of their actions. Unlike Oedipus, however, t he Communists use their ignorance to absolve themselves of guilt, and remain in power. Tomas praised Oedipus for accepting responsibility for his actions, and faulted the Communists for using lack of knowledge to explain away wrongdoing.
Tomas thinks it over and notices that everyone in the hospital is smiling at him; they want him to sign and renounce moral superiority over them. Sickened by the smiles, Tomas refuses to sign the retraction, and loses his job. He finds a new job working in a clinic as a general practitioner.
One day a man from the Ministry of the Interior approaches him. The man asks Tomas to sign a statement saying that Tomas was used by the editors of the journal that published the Oedipus article. Tomas begins to understand that the police can easily forge his signature, and use it to publicly humiliate him. In order to escape, Tomas decides to become utterly unimportant. He starts a new career as a window-washer.
Surgery had been the one consistent Ess muss sein! or It must be! (a phrase taken from Beethoven) in Tomas's life, yet he gives it up almost with relief. Now his life is lighter still and it is harder for anyone to hurt him. (The narrator says that Beethoven's inspiration for the refrain (Ess muss sein came from a joke, his reply to someone who owed him money and asked him if he really had to pay him back immediately.) Tomas, rejecting heaviness again, "roamed the streets of Prague with brush and pole, feeling ten years younger." Tomas begins womanizing in earnest again.
Tomas has slept with at least 200 different women. Rather than searching endlessly for one ideal woman, or sleeping with women merely for physical pleasure, he appreciates each woman as a unique individual. He approaches women in the same way he approache d patients, trying to find out what makes the individual in question different from everyone else on the planet. The narrator says that if two classes of womanizer exist, lyric and epic, Tomas falls into the epic class, because everything interests him an d nothing disappoints him.
Tomas has one affair with an interesting young woman, whose appearance he compares to a stork or giraffe or young boy. She refuses to strip at his command, and defies many of his expectations. Her originality intrigues Tomas.
Tomas runs into a former lover who reminds him of a poetic moment when they made love during a storm. Tomas has no memory of the incident, and realizes that Tereza occupies all of his poetic memory. With other women, he acts the doctor or explorer.
Two dissidents contact Tomas, an editor with a big chin and Tomas's son. Both men admire Tomas's courageous refusal to comply with the police. However, they too want him to sign something—a petition against the rough treatment of political prisoners. Tomas stares at his son, noticing he stammers and blushes. Tomas feels his relationship with his son is at stake; also, the glamour of being an important dissident tempts him. At the same time, he realizes that like the chief surgeon and the man from the Ministry of the Interior, these dissidents want him to sign something he did not write. At the last moment he thinks of Tereza, who has complained of being harassed by the secret police. He refuses to sign.
The papers publish news of the petition the next day, and vilify all who signed. Tomas wonders whether he should have signed, and considers the history of the Czech people. He suspects the history is coming to an end. A random encounter with a girl he had forgotten to seduce reminds him that he is aging as well. He has grown increasingly estranged from Tereza. Tereza suggests they move to the country; Tomas knows this would mean finally giving up on his womanizing. Tomas thinks how ridiculous it is that sex and love are somehow linked in the human brain, and thinks in an ideal world he would be excited at the sight of a swallow instead of a woman, so as not to upset Tereza. He imagines life with some ideal woman, a version of himself, and realizes he would leave any happiness behind for Tereza.
This chapter finally explains the Oedipus article for which Tomas has been blacklisted. In keeping with Tomas's character, the article is more humorous, intellectual and philosophical than overtly political. He points out a clever parable and logical mistake, but never means to join the ranks of the dissidents.
Tomas seems to gain self-knowledge as he grows older; in his encounter with the giraffe-like woman, and his classification as an epic womanizer, he demonstrates a clearer understanding of himself and his motivations that he has previously.
In some ways, Tomas remains the light man he has always been. He leaves his work, his hospital, the dissidents, and his son in order to maintain lightness. In another sense, however, Tomas becomes more heavy in this section of the novel. He acts on principle when he refuses to sign the various documents; moreover, his love life eventually becomes more weighty. Although in the first part of the chapter Tomas and Tereza are estranged, a significant change occurs at the end of the chapter when Tomas realizes that he ranks Tereza's happiness first in importance. He ultimately decides to give up his extramarital affairs for her sake. His love for Tereza has finally acquired weight.